2.3.0 (#5043)

* Move analytics initialization into docs.coffee

* Bump Bootstrap and CodeMirror versions

* Update output

* Merge CodeMirror styles

* Update CodeMirror styles

* Better flexbox layout for docs, including flex auto-sized sidebar and main column

* Minor styling fixes for Edge

* Fix scrollspy for new layout

* Update output

* Clicking on the CoffeeScript logo in the navbar should scroll to top; fix main column width on mobile

* Update output

* 2.3.0 changelog

* Update operators section for **

* Update docs for ES2018 object rest/spread

* Remove references to Node's experimental modules support

* Move the README coffee cup to the right side, so our name isn't cut off on the NPM page; update README and CONTRIBUTING text

* Update dependencies

* Add compatibility note for async generators

* Bump version to 2.3.0 and update output

* Have CI test in Node 10 instead of 9

* Somehow this gets generated slightly differently in Node 10

* Fix #4042: Update broken link

.travis.yml

@@ -3,6 +3,7 @@ language: node_js
 node_js:
   - 6
   - 8
+  - 10
 
 cache:
   directories:
@@ -14,5 +15,6 @@ script:
   - node ./bin/cake build:full
   - node ./bin/cake build:browser
   - node ./bin/cake test
+  - node --harmony ./bin/cake test
   - node ./bin/cake test:browser
   - node ./bin/cake test:integrations

CODE_OF_CONDUCT.md

@@ -0,0 +1,46 @@
+# Contributor Covenant Code of Conduct
+
+## Our Pledge
+
+In the interest of fostering an open and welcoming environment, we as contributors and maintainers pledge to making participation in our project and our community a harassment-free experience for everyone, regardless of age, body size, disability, ethnicity, gender identity and expression, level of experience, nationality, personal appearance, race, religion, or sexual identity and orientation.
+
+## Our Standards
+
+Examples of behavior that contributes to creating a positive environment include:
+
+* Using welcoming and inclusive language
+* Being respectful of differing viewpoints and experiences
+* Gracefully accepting constructive criticism
+* Focusing on what is best for the community
+* Showing empathy towards other community members
+
+Examples of unacceptable behavior by participants include:
+
+* The use of sexualized language or imagery and unwelcome sexual attention or advances
+* Trolling, insulting/derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or electronic address, without explicit permission
+* Other conduct which could reasonably be considered inappropriate in a professional setting
+
+## Our Responsibilities
+
+Project maintainers are responsible for clarifying the standards of acceptable behavior and are expected to take appropriate and fair corrective action in response to any instances of unacceptable behavior.
+
+Project maintainers have the right and responsibility to remove, edit, or reject comments, commits, code, wiki edits, issues, and other contributions that are not aligned to this Code of Conduct, or to ban temporarily or permanently any contributor for other behaviors that they deem inappropriate, threatening, offensive, or harmful.
+
+## Scope
+
+This Code of Conduct applies both within project spaces and in public spaces when an individual is representing the project or its community. Examples of representing a project or community include using an official project e-mail address, posting via an official social media account, or acting as an appointed representative at an online or offline event. Representation of a project may be further defined and clarified by project maintainers.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be reported by contacting the project team at maintainers@coffeescript.org. The project team will review and investigate all complaints, and will respond in a way that it deems appropriate to the circumstances. The project team is obligated to maintain confidentiality with regard to the reporter of an incident. Further details of specific enforcement policies may be posted separately.
+
+Project maintainers who do not follow or enforce the Code of Conduct in good faith may face temporary or permanent repercussions as determined by other members of the project's leadership.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4, available at [http://contributor-covenant.org/version/1/4][version]
+
+[homepage]: http://contributor-covenant.org
+[version]: http://contributor-covenant.org/version/1/4/

CONTRIBUTING.md

@@ -6,4 +6,9 @@
 
 * Use the same coding style as the rest of the [codebase](https://github.com/jashkenas/coffeescript/tree/master/src). If you’re just getting started with CoffeeScript, there’s a nice [style guide](https://github.com/polarmobile/coffeescript-style-guide).
 
-* In your pull request, do not add documentation to `index.html` or re-build the minified `coffeescript.js` file. We’ll do those things before cutting a new release. You _should,_ however, commit the updated compiled JavaScript files in `lib`.
+* In your pull request, do not add documentation to `index.html` or re-build the minified `coffeescript.js` file. We’ll do those things before cutting a new release. You _should,_ however, commit the updated compiled JavaScript files in `lib`.
+
+* To get started, read the guides in the wiki:
+	* [Hacking on the CoffeeScript Compiler](https://github.com/jashkenas/coffeescript/wiki/%5BHowTo%5D-Hacking-on-the-CoffeeScript-Compiler)
+	* [How parsing works](https://github.com/jashkenas/coffeescript/wiki/%5BHowTo%5D-How-parsing-works)
+	* [Update the docs](https://github.com/jashkenas/coffeescript/wiki/%5BHowTo%5D-Update-the-docs)

Cakefile

@@ -332,7 +332,7 @@ task 'doc:test:watch', 'watch and continually rebuild the browser-based tests',
 
 buildAnnotatedSource = (watch = no) ->
   do generateAnnotatedSource = ->
-    exec "node_modules/docco/bin/docco src/*.*coffee --output docs/v#{majorVersion}/annotated-source", (err) -> throw err if err
+    exec "cd src && ../node_modules/docco/bin/docco *.*coffee --output ../docs/v#{majorVersion}/annotated-source", (err) -> throw err if err
     log 'generated', green, "annotated source in docs/v#{majorVersion}/annotated-source/"
 
   if watch
@@ -425,12 +425,6 @@ runTests = (CoffeeScript) ->
     catch err
       onFail description, fn, err
 
-  global.supportsAsync = try
-      new Function('async () => {}')()
-      yes
-    catch
-      no
-
   helpers.extend global, require './test/support/helpers'
 
   # When all the tests have run, collect and print errors.
@@ -448,10 +442,20 @@ runTests = (CoffeeScript) ->
       console.log "  #{source}" if source
     return
 
-  # Run every test in the `test` folder, recording failures.
-  files = fs.readdirSync 'test'
-  unless global.supportsAsync # Except for async tests, if async isn’t supported.
-    files = files.filter (filename) -> filename isnt 'async.coffee'
+  # Run every test in the `test` folder, recording failures, except for files
+  # we’re skipping because the features to be tested are unsupported in the
+  # current Node runtime.
+  testFilesToSkip = []
+  skipUnless = (featureDetect, filenames) ->
+    unless (try new Function featureDetect)
+      testFilesToSkip = testFilesToSkip.concat filenames
+  skipUnless 'async () => {}', ['async.coffee', 'async_iterators.coffee']
+  skipUnless 'async function* generator() { yield 42; }', ['async_iterators.coffee']
+  skipUnless 'var a = 2 ** 2; a **= 3', ['exponentiation.coffee']
+  skipUnless 'var {...a} = {}', ['object_rest_spread.coffee']
+  skipUnless '/foo.bar/s.test("foo\tbar")', ['regex_dotall.coffee']
+  files = fs.readdirSync('test').filter (filename) ->
+    filename not in testFilesToSkip
 
   startTime = Date.now()
   for file in files when helpers.isCoffee file

ISSUE_TEMPLATE.md

@@ -0,0 +1,62 @@
+<!---
+Thanks for filing an issue 😄! Before you submit, please read the following:
+
+Search open/closed issues before submitting since someone might have asked the same thing before!
+Our issues history stretches back to 2009, so the odds are good that your topic has come up.
+
+If you have a support request or question please use Stack Overflow:
+https://stackoverflow.com/questions/tagged/coffeescript
+
+Issues on GitHub are only related to problems of the CoffeeScript compiler itself and we cannot answer 
+support questions here.
+-->
+
+Choose one: is this a bug report or feature request?
+
+<!---
+Provide a general summary of the issue in the title above.
+
+For bugs, please also preface your title with “Bug:”. For feature requests, please preface your title
+with “Proposal:”. Once your issue is reviewed, a maintainer will edit the title to refer to the part
+of the codebase most relevant to the issue (if applicable).
+
+If your request is that CoffeeScript support a new feature recently arrived to JavaScript, please note
+that we generally only add features that have reached Stage 4 in the specification (in other words, 
+the syntax is finalized and the feature is approved to be part of the next ES release). You can still
+open an issue, but it will likely be tagged with “[Awaiting Stage 4]” until the relevant ES feature is
+approved for release. See http://coffeescript.org/#contributing
+
+There are also a handful of JavaScript features that CoffeeScript intentionally does not support.
+Please do not open issues regarding these. They’re listed in http://coffeescript.org/#unsupported
+-->
+
+### Input Code
+<!--- If you're describing a bug, please let us know which sample code reproduces your problem. -->
+<!--- If you have link from http://coffeescript.org/#try or a standalone repo please include that! -->
+
+```coffee
+your (code) => here
+```
+
+### Expected Behavior
+<!--- If you’re describing a bug, tell us what should happen. -->
+<!--- If you’re suggesting a change/improvement, tell us how it should work. -->
+
+### Current Behavior
+<!--- If describing a bug, tell us what happens instead of the expected behavior. -->
+<!--- If suggesting a change/improvement, explain the difference from current behavior. -->
+
+### Possible Solution
+<!--- Not obligatory, but suggest a fix/reason for the bug, -->
+<!--- or ideas how to implement the addition or change. -->
+
+### Context
+<!--- How has this issue affected you? What are you trying to accomplish? -->
+<!--- Providing context helps us come up with a solution that is most useful in the real world. -->
+
+### Environment
+<!--- For bugs, please let us know what version of CoffeeScript you’re running: `coffee -v`. -->
+<!--- If you think it might be relevant, please also let us know your version of Node. -->
+
+* CoffeeScript version:
+* Node.js version:

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2009-2017 Jeremy Ashkenas
+Copyright (c) 2009-2018 Jeremy Ashkenas
 
 Permission is hereby granted, free of charge, to any person
 obtaining a copy of this software and associated documentation

PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,22 @@
+<!--
+Before making a PR please make sure to read our contributing guidelines:
+http://coffeescript.org/#contributing
+
+For issue references: Add a comma-separated list of a 
+[closing word](https://help.github.com/articles/closing-issues-via-commit-messages/) followed by 
+the ticket number fixed by the PR. It should be underlined in the preview if done correctly.
+
+All new features require tests. All but the most trivial bug fixes should also have new or updated tests.
+
+Ensure that all new code you add to the compiler can be run in the minimum version of Node listed in 
+`package.json`. New tests can require newer Node runtimes, but you may need to ensure that such tests
+only run in supported runtimes; see `Cakefile` for examples of how to filter out certain tests in 
+runtimes that don’t support them.
+
+Please follow the code style of the rest of the CoffeeScript codebase. Write comments in complete
+sentences using Markdown, as the comments become the [annotated source](http://coffeescript.org/#annotated-source).
+For tests proving a bug is fixed, please mention the issue number in the test description (see examples
+in the codebase).
+
+Describe your changes below in as much detail as possible.
+-->

README.md

@@ -1,27 +1,27 @@
-                                               @@@@@@@                @@@@  @@@@@
-                    {                         @@@@@@@@@@              @@@   @@@
-                 }   }   {                   @@@@     @@              @@@   @@@
-                {   {  }  }                 @@@@          @@@@@@@    @@@   @@@     @@@@@@    @@@@@@
-                 }   }{  {                 @@@@          @@@   @@  @@@@@  @@@@@@  @@@   @@  @@@@  @@
-                {  }{  }  }                @@@@         @@@@   @@   @@@    @@@   @@@   @@@ @@@   @@@
-               { }{ }{  { }                @@@@        @@@@    @@   @@@    @@@   @@@@@@@@  @@@@@@@@
-             {  { } { } { }  }             @@@@@       @@@@   @@    @@@    @@@   @@@       @@@
-              { }   { }   { }               @@@@@@@@@@ @@@@@@@@    @@@    @@@    @@@@@@@@  @@@@@@@@
-       @@@@@@   { }   { }    @@@@@@@           @@@@@               @@@    @@@      @@@@@     @@@@@
-       @@@@@@@@@@@@@@@@@@@@@@@@@@@@                               @@@    @@@
-     @@ @@@@@@@@@@@@@@@@@@@@@@@@@@             @@@@@@            @@@    @@@
-    @@   @@@@@@@@@@@@@@@@@@@@@@@@           @@@@    @@          @@@   @@@@
-    @@@   @@@@@@@@@@@@@@@@@@@@@             @@@@   @@@                       @@                  @@@@
-     @@@    @@@@@@@@@@@@@@@@@@              @@@@@          @@@@@   @@  @@   @@@     @@@@@@@     @@@@@
-       @@@   @@@@@@@@@@@@@@@@                 @@@@@      @@@  @@@ @@@@@@@@         @@@@  @@@@  @@@@@@@
-              @@@@@@@@@@@@@@                    @@@@@   @@@       @@@@     @@@@    @@@    @@@   @@@
-                                          @@@@@  @@@@  @@@@      @@@@      @@@@   @@@@   @@@@  @@@@
-                                         @@@     @@@@  @@@       @@@@     @@@@    @@@    @@@@  @@@@
-                                         @@@     @@@@  @@@@     @@@@      @@@@   @@@@   @@@@  @@@@
-                                          @@@@@@@@@     @@@@@@  @@@@       @@@@  @@@@@@@@@    @@@@
-                                                                                 @@@          @@@@
-                                                                                @@@
-                                                                                @@@
+      @@@@@@@                @@@@  @@@@@
+     @@@@@@@@@@              @@@   @@@                                           {
+    @@@@     @@              @@@   @@@                                        }   }   {
+   @@@@          @@@@@@@    @@@   @@@     @@@@@@    @@@@@@                   {   {  }  }
+  @@@@          @@@   @@  @@@@@  @@@@@@  @@@   @@  @@@@  @@                   }   }{  {
+  @@@@         @@@@   @@   @@@    @@@   @@@   @@@ @@@   @@@                  {  }{  }  }
+  @@@@        @@@@    @@   @@@    @@@   @@@@@@@@  @@@@@@@@                  { }{ }{  { }
+  @@@@@       @@@@   @@    @@@    @@@   @@@       @@@                     {  { } { } { }  }
+   @@@@@@@@@@ @@@@@@@@    @@@    @@@    @@@@@@@@  @@@@@@@@                 { }   { }   { }
+      @@@@@               @@@    @@@      @@@@@     @@@@@           @@@@@@   { }   { }    @@@@@@@
+                         @@@    @@@                                 @@@@@@@@@@@@@@@@@@@@@@@@@@@@
+      @@@@@@            @@@    @@@                                @@ @@@@@@@@@@@@@@@@@@@@@@@@@@
+   @@@@    @@          @@@   @@@@                                @@   @@@@@@@@@@@@@@@@@@@@@@@@
+   @@@@   @@@                       @@                  @@@@     @@@   @@@@@@@@@@@@@@@@@@@@@
+   @@@@@          @@@@@   @@  @@   @@@     @@@@@@@     @@@@@      @@@    @@@@@@@@@@@@@@@@@@
+     @@@@@      @@@  @@@ @@@@@@@@         @@@@  @@@@  @@@@@@@       @@@   @@@@@@@@@@@@@@@@
+       @@@@@   @@@       @@@@     @@@@    @@@    @@@   @@@                 @@@@@@@@@@@@@@
+ @@@@@  @@@@  @@@@      @@@@      @@@@   @@@@   @@@@  @@@@
+@@@     @@@@  @@@       @@@@     @@@@    @@@    @@@@  @@@@
+@@@     @@@@  @@@@     @@@@      @@@@   @@@@   @@@@  @@@@
+ @@@@@@@@@     @@@@@@  @@@@       @@@@  @@@@@@@@@    @@@@
+                                       @@@          @@@@
+                                      @@@
+                                      @@@
 
 CoffeeScript is a little language that compiles into JavaScript.
 
@@ -30,11 +30,13 @@ CoffeeScript is a little language that compiles into JavaScript.
 Once you have Node.js installed:
 
 ```shell
+# Install locally for a project:
+npm install --save-dev coffeescript
+
+# Install globally to execute .coffee files anywhere:
 npm install --global coffeescript
 ```
 
-Leave off the `--global` if you don’t wish to install globally.
-
 ## Getting Started
 
 Execute a script:

appveyor.yml

@@ -0,0 +1,29 @@
+environment:
+  matrix:
+    - nodejs_version: '6'
+    - nodejs_version: '8'
+    - nodejs_version: '10'
+    - nodejs_version: '' # Installs latest.
+
+install:
+  - ps: Install-Product node $env:nodejs_version
+  - node --version
+  - npm --version
+  - npm install
+
+cache:
+  - node_modules
+
+test_script:
+  - node ./bin/cake build:except-parser
+  - node ./bin/cake build:parser
+  - node ./bin/cake build:full
+  - node ./bin/cake build:browser
+  - node ./bin/cake test
+  - node --harmony ./bin/cake test
+  - node ./bin/cake test:browser
+  - node ./bin/cake test:integrations
+
+build: off
+
+version: "{build}"

bin/cake

@@ -1,5 +1,12 @@
 #!/usr/bin/env node
 
+try {
+  new Function('var {a} = {a: 1}')();
+} catch (error) {
+  console.error('Your JavaScript runtime does not support some features used by the cake command. Please use Node 6 or later.');
+  process.exit(1);
+}
+
 var path = require('path');
 var fs   = require('fs');
 

bin/coffee

@@ -1,5 +1,12 @@
 #!/usr/bin/env node
 
+try {
+  new Function('var {a} = {a: 1}')();
+} catch (error) {
+  console.error('Your JavaScript runtime does not support some features used by the coffee command. Please use Node 6 or later.');
+  process.exit(1);
+}
+
 var path = require('path');
 var fs   = require('fs');
 

docs/v2/annotated-source/coffeescript.html

@@ -480,7 +480,9 @@ is run via the CLI or Node API.</p>
             </div>
             
             <div class="content"><div class='highlight'><pre>    transpiler = options.transpile.transpile
-    <span class="hljs-keyword">delete</span> options.transpile.transpile</pre></div></div>
+    <span class="hljs-keyword">delete</span> options.transpile.transpile
+
+    transpilerOptions = Object.assign {}, options.transpile</pre></div></div>
             
         </li>
         
@@ -497,9 +499,9 @@ and it will return an <em>updated</em> v3 source map object in its output.</p>
 
             </div>
             
-            <div class="content"><div class='highlight'><pre>    <span class="hljs-keyword">if</span> v3SourceMap <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> options.transpile.inputSourceMap?
-      options.transpile.inputSourceMap = v3SourceMap
-    transpilerOutput = transpiler js, options.transpile
+            <div class="content"><div class='highlight'><pre>    <span class="hljs-keyword">if</span> v3SourceMap <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> transpilerOptions.inputSourceMap?
+      transpilerOptions.inputSourceMap = v3SourceMap
+    transpilerOutput = transpiler js, transpilerOptions
     js = transpilerOutput.code
     <span class="hljs-keyword">if</span> v3SourceMap <span class="hljs-keyword">and</span> transpilerOutput.map
       v3SourceMap = transpilerOutput.map

docs/v2/annotated-source/command.html

@@ -749,7 +749,7 @@ same directory as the <code>.js</code> file.</p>
             </div>
             
             <div class="content"><div class='highlight'><pre><span class="hljs-function"><span class="hljs-title">writeJs</span> = <span class="hljs-params">(base, sourcePath, js, jsPath, generatedSourceMap = <span class="hljs-literal">null</span>)</span> -&gt;</span>
-  sourceMapPath = outputPath sourcePath, base, <span class="hljs-string">".js.map"</span>
+  sourceMapPath = <span class="hljs-string">"<span class="hljs-subst">#{jsPath}</span>.map"</span>
   jsDir  = path.dirname jsPath
 <span class="hljs-function">  <span class="hljs-title">compile</span> = -&gt;</span>
     <span class="hljs-keyword">if</span> opts.compile

docs/v2/annotated-source/lexer.html

@@ -461,13 +461,17 @@ what CoffeeScript would normally interpret as calls to functions named
             </div>
             
             <div class="content"><div class='highlight'><pre>    <span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> tag <span class="hljs-keyword">is</span> <span class="hljs-string">'PROPERTY'</span> <span class="hljs-keyword">and</span> prev
-      <span class="hljs-keyword">if</span> prev.spaced <span class="hljs-keyword">and</span> prev[<span class="hljs-number">0</span>] <span class="hljs-keyword">in</span> CALLABLE <span class="hljs-keyword">and</span> <span class="hljs-regexp">/^[gs]et$/</span>.test(prev[<span class="hljs-number">1</span>]) <span class="hljs-keyword">and</span> @tokens[@tokens.length - <span class="hljs-number">2</span>][<span class="hljs-number">0</span>] <span class="hljs-keyword">isnt</span> <span class="hljs-string">'.'</span>
-        @error <span class="hljs-string">"'<span class="hljs-subst">#{prev[<span class="hljs-number">1</span>]}</span>' cannot be used as a keyword, or as a function call without parentheses"</span>, prev[<span class="hljs-number">2</span>]
-      <span class="hljs-keyword">else</span>
+      <span class="hljs-keyword">if</span> prev.spaced <span class="hljs-keyword">and</span> prev[<span class="hljs-number">0</span>] <span class="hljs-keyword">in</span> CALLABLE <span class="hljs-keyword">and</span> <span class="hljs-regexp">/^[gs]et$/</span>.test(prev[<span class="hljs-number">1</span>]) <span class="hljs-keyword">and</span>
+         @tokens.length &gt; <span class="hljs-number">1</span> <span class="hljs-keyword">and</span> @tokens[@tokens.length - <span class="hljs-number">2</span>][<span class="hljs-number">0</span>] <span class="hljs-keyword">not</span> <span class="hljs-keyword">in</span> [<span class="hljs-string">'.'</span>, <span class="hljs-string">'?.'</span>, <span class="hljs-string">'@'</span>]
+        @error <span class="hljs-string">"'<span class="hljs-subst">#{prev[<span class="hljs-number">1</span>]}</span>' cannot be used as a keyword, or as a function call
+        without parentheses"</span>, prev[<span class="hljs-number">2</span>]
+      <span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> @tokens.length &gt; <span class="hljs-number">2</span>
         prevprev = @tokens[@tokens.length - <span class="hljs-number">2</span>]
-        <span class="hljs-keyword">if</span> prev[<span class="hljs-number">0</span>] <span class="hljs-keyword">in</span> [<span class="hljs-string">'@'</span>, <span class="hljs-string">'THIS'</span>] <span class="hljs-keyword">and</span> prevprev <span class="hljs-keyword">and</span> prevprev.spaced <span class="hljs-keyword">and</span> <span class="hljs-regexp">/^[gs]et$/</span>.test(prevprev[<span class="hljs-number">1</span>]) <span class="hljs-keyword">and</span>
-        @tokens[@tokens.length - <span class="hljs-number">3</span>][<span class="hljs-number">0</span>] <span class="hljs-keyword">isnt</span> <span class="hljs-string">'.'</span>
-          @error <span class="hljs-string">"'<span class="hljs-subst">#{prevprev[<span class="hljs-number">1</span>]}</span>' cannot be used as a keyword, or as a function call without parentheses"</span>, prevprev[<span class="hljs-number">2</span>]
+        <span class="hljs-keyword">if</span> prev[<span class="hljs-number">0</span>] <span class="hljs-keyword">in</span> [<span class="hljs-string">'@'</span>, <span class="hljs-string">'THIS'</span>] <span class="hljs-keyword">and</span> prevprev <span class="hljs-keyword">and</span> prevprev.spaced <span class="hljs-keyword">and</span>
+           <span class="hljs-regexp">/^[gs]et$/</span>.test(prevprev[<span class="hljs-number">1</span>]) <span class="hljs-keyword">and</span>
+           @tokens[@tokens.length - <span class="hljs-number">3</span>][<span class="hljs-number">0</span>] <span class="hljs-keyword">not</span> <span class="hljs-keyword">in</span> [<span class="hljs-string">'.'</span>, <span class="hljs-string">'?.'</span>, <span class="hljs-string">'@'</span>]
+          @error <span class="hljs-string">"'<span class="hljs-subst">#{prevprev[<span class="hljs-number">1</span>]}</span>' cannot be used as a keyword, or as a
+          function call without parentheses"</span>, prevprev[<span class="hljs-number">2</span>]
 
     <span class="hljs-keyword">if</span> tag <span class="hljs-keyword">is</span> <span class="hljs-string">'IDENTIFIER'</span> <span class="hljs-keyword">and</span> id <span class="hljs-keyword">in</span> RESERVED
       @error <span class="hljs-string">"reserved word '<span class="hljs-subst">#{id}</span>'"</span>, length: id.length
@@ -915,9 +919,11 @@ can close multiple indents, so we need to know how far in we happen to be.</p>
     <span class="hljs-keyword">return</span> <span class="hljs-number">0</span> <span class="hljs-keyword">unless</span> match = MULTI_DENT.exec chunk
     indent = match[<span class="hljs-number">0</span>]
 
-    @seenFor = <span class="hljs-literal">no</span>
-    @seenImport = <span class="hljs-literal">no</span> <span class="hljs-keyword">unless</span> @importSpecifierList
-    @seenExport = <span class="hljs-literal">no</span> <span class="hljs-keyword">unless</span> @exportSpecifierList
+    prev = @prev()
+    backslash = prev?[<span class="hljs-number">0</span>] <span class="hljs-keyword">is</span> <span class="hljs-string">'\\'</span>
+    @seenFor = <span class="hljs-literal">no</span> <span class="hljs-keyword">unless</span> backslash <span class="hljs-keyword">and</span> @seenFor
+    @seenImport = <span class="hljs-literal">no</span> <span class="hljs-keyword">unless</span> (backslash <span class="hljs-keyword">and</span> @seenImport) <span class="hljs-keyword">or</span> @importSpecifierList
+    @seenExport = <span class="hljs-literal">no</span> <span class="hljs-keyword">unless</span> (backslash <span class="hljs-keyword">and</span> @seenExport) <span class="hljs-keyword">or</span> @exportSpecifierList
 
     size = indent.length - <span class="hljs-number">1</span> - indent.lastIndexOf <span class="hljs-string">'\n'</span>
     noNewlines = @unfinished()
@@ -938,7 +944,7 @@ can close multiple indents, so we need to know how far in we happen to be.</p>
 
     <span class="hljs-keyword">if</span> size &gt; @indent
       <span class="hljs-keyword">if</span> noNewlines
-        @indebt = size - @indent
+        @indebt = size - @indent <span class="hljs-keyword">unless</span> backslash
         @suppressNewlines()
         <span class="hljs-keyword">return</span> indent.length
       <span class="hljs-keyword">unless</span> @tokens.length
@@ -1121,7 +1127,7 @@ comments that trail it.</p>
             
             <div class="content"><div class='highlight'><pre>    prevChar = <span class="hljs-keyword">if</span> @tokens.length &gt; <span class="hljs-number">0</span> <span class="hljs-keyword">then</span> @tokens[@tokens.length - <span class="hljs-number">1</span>][<span class="hljs-number">0</span>] <span class="hljs-keyword">else</span> <span class="hljs-string">''</span>
     <span class="hljs-keyword">if</span> firstChar <span class="hljs-keyword">is</span> <span class="hljs-string">'&lt;'</span>
-      match = CSX_IDENTIFIER.exec @chunk[<span class="hljs-number">1.</span>..]
+      match = CSX_IDENTIFIER.exec(@chunk[<span class="hljs-number">1.</span>..]) <span class="hljs-keyword">or</span> CSX_FRAGMENT_IDENTIFIER.exec(@chunk[<span class="hljs-number">1.</span>..])
       <span class="hljs-keyword">return</span> <span class="hljs-number">0</span> <span class="hljs-keyword">unless</span> match <span class="hljs-keyword">and</span> (
         @csxDepth &gt; <span class="hljs-number">0</span> <span class="hljs-keyword">or</span></pre></div></div>
             
@@ -1187,8 +1193,8 @@ comments that trail it.</p>
           @matchWithInterpolations INSIDE_CSX, <span class="hljs-string">'&gt;'</span>, <span class="hljs-string">'&lt;/'</span>, CSX_INTERPOLATION
         @mergeInterpolationTokens tokens, {delimiter: <span class="hljs-string">'"'</span>}, <span class="hljs-function"><span class="hljs-params">(value, i)</span> =&gt;</span>
           @formatString value, delimiter: <span class="hljs-string">'&gt;'</span>
-        match = CSX_IDENTIFIER.exec @chunk[end...]
-        <span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> match <span class="hljs-keyword">or</span> match[<span class="hljs-number">0</span>] <span class="hljs-keyword">isnt</span> csxTag.name
+        match = CSX_IDENTIFIER.exec(@chunk[end...]) <span class="hljs-keyword">or</span> CSX_FRAGMENT_IDENTIFIER.exec(@chunk[end...])
+        <span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> match <span class="hljs-keyword">or</span> match[<span class="hljs-number">1</span>] <span class="hljs-keyword">isnt</span> csxTag.name
           @error <span class="hljs-string">"expected corresponding CSX closing tag for <span class="hljs-subst">#{csxTag.name}</span>"</span>,
             csxTag.origin[<span class="hljs-number">2</span>]
         afterTag = end + csxTag.name.length
@@ -1641,8 +1647,8 @@ of <code>&#39;NEOSTRING&#39;</code>s are converted using <code>fn</code> and tur
                 <a class="pilcrow" href="#section-58">&#182;</a>
               </div>
               <p>This is an interpolated string, not a CSX tag; and for whatever
-reason <code>`a${/*test*/}b` </code> is invalid JS. So compile to
-<code>`a${/*test*/&#39;&#39;}b` </code> instead.</p>
+reason <code>`a${/*test*/}b`</code> is invalid JS. So compile to
+<code>`a${/*test*/&#39;&#39;}b`</code> instead.</p>
 
             </div>
             
@@ -2458,6 +2464,23 @@ be used as identifiers or properties.</p>
 CSX_IDENTIFIER = <span class="hljs-regexp">/// ^
   (?![\d&lt;]) <span class="hljs-comment"># Must not start with `&lt;`.</span>
   ( (?: (?!\s)[\.\-$\w\x7f-\uffff] )+ ) <span class="hljs-comment"># Like `IDENTIFIER`, but includes `-`s and `.`s.</span>
+///</span></pre></div></div>
+            
+        </li>
+        
+        
+        <li id="section-98">
+            <div class="annotation">
+              
+              <div class="pilwrap ">
+                <a class="pilcrow" href="#section-98">&#182;</a>
+              </div>
+              <p>Fragment: &lt;&gt;&lt;/&gt;</p>
+
+            </div>
+            
+            <div class="content"><div class='highlight'><pre>CSX_FRAGMENT_IDENTIFIER = <span class="hljs-regexp">/// ^
+  ()&gt; <span class="hljs-comment"># Ends immediately with `&gt;`.</span>
 ///</span>
 
 CSX_ATTRIBUTE = <span class="hljs-regexp">/// ^
@@ -2497,11 +2520,11 @@ HERE_JSTOKEN = <span class="hljs-regexp">///^ ```     ((?: [^`\\] | \\[\s\S] | `
         </li>
         
         
-        <li id="section-98">
+        <li id="section-99">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-98">&#182;</a>
+                <a class="pilcrow" href="#section-99">&#182;</a>
               </div>
               <p>String-matching-regexes.</p>
 
@@ -2535,11 +2558,11 @@ HEREDOC_INDENT     = <span class="hljs-regexp">/\n+([^\n\S]*)(?=\S)/g</span></pr
         </li>
         
         
-        <li id="section-99">
+        <li id="section-100">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-99">&#182;</a>
+                <a class="pilcrow" href="#section-100">&#182;</a>
               </div>
               <p>Regex-matching-regexes.</p>
 
@@ -2556,9 +2579,88 @@ HEREDOC_INDENT     = <span class="hljs-regexp">/\n+([^\n\S]*)(?=\S)/g</span></pr
 ///</span>
 
 REGEX_FLAGS  = <span class="hljs-regexp">/^\w*/</span>
-VALID_FLAGS  = <span class="hljs-regexp">/^(?!.*(.).*\1)[imguy]*$/</span>
+VALID_FLAGS  = <span class="hljs-regexp">/^(?!.*(.).*\1)[gimsuy]*$/</span>
 
-HEREGEX      = <span class="hljs-regexp">/// ^(?: [^\\/<span class="hljs-comment">#] | \\[\s\S] | /(?!//) | \#(?!\{) )* ///</span>
+HEREGEX      = <span class="hljs-regexp">/// ^
+  (?:
+</span></pre></div></div>
+            
+        </li>
+        
+        
+        <li id="section-101">
+            <div class="annotation">
+              
+              <div class="pilwrap ">
+                <a class="pilcrow" href="#section-101">&#182;</a>
+              </div>
+              <p>Match any character, except those that need special handling below.</p>
+
+            </div>
+            
+            <div class="content"><div class='highlight'><pre>      [^\\/<span class="hljs-comment">#\s]</span></pre></div></div>
+            
+        </li>
+        
+        
+        <li id="section-102">
+            <div class="annotation">
+              
+              <div class="pilwrap ">
+                <a class="pilcrow" href="#section-102">&#182;</a>
+              </div>
+              <p>Match <code>\</code> followed by any character.</p>
+
+            </div>
+            
+            <div class="content"><div class='highlight'><pre>    | \\[\s\S]</pre></div></div>
+            
+        </li>
+        
+        
+        <li id="section-103">
+            <div class="annotation">
+              
+              <div class="pilwrap ">
+                <a class="pilcrow" href="#section-103">&#182;</a>
+              </div>
+              <p>Match any <code>/</code> except <code>///</code>.</p>
+
+            </div>
+            
+            <div class="content"><div class='highlight'><pre>    | <span class="hljs-regexp">/(?!/</span>/)</pre></div></div>
+            
+        </li>
+        
+        
+        <li id="section-104">
+            <div class="annotation">
+              
+              <div class="pilwrap ">
+                <a class="pilcrow" href="#section-104">&#182;</a>
+              </div>
+              <p>Match <code>#</code> which is not part of interpolation, e.g. <code>#{}</code>.</p>
+
+            </div>
+            
+            <div class="content"><div class='highlight'><pre>    | \<span class="hljs-comment">#(?!\{)</span></pre></div></div>
+            
+        </li>
+        
+        
+        <li id="section-105">
+            <div class="annotation">
+              
+              <div class="pilwrap ">
+                <a class="pilcrow" href="#section-105">&#182;</a>
+              </div>
+              <p>Comments consume everything until the end of the line, including <code>///</code>.</p>
+
+            </div>
+            
+            <div class="content"><div class='highlight'><pre>    | \s+(?:<span class="hljs-comment">#(?!\{).*)?</span>
+  )*
+<span class="hljs-regexp">///
 
 HEREGEX_OMIT = ///</span>
     ((?:\\\\)+)     <span class="hljs-comment"># Consume (and preserve) an even number of backslashes.</span>
@@ -2573,11 +2675,11 @@ POSSIBLY_DIVISION   = <span class="hljs-regexp">/// ^ /=?\s ///</span></pre></di
         </li>
         
         
-        <li id="section-100">
+        <li id="section-106">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-100">&#182;</a>
+                <a class="pilcrow" href="#section-106">&#182;</a>
               </div>
               <p>Other regexes.</p>
 
@@ -2620,11 +2722,11 @@ TRAILING_SPACES     = <span class="hljs-regexp">/\s+$/</span></pre></div></div>
         </li>
         
         
-        <li id="section-101">
+        <li id="section-107">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-101">&#182;</a>
+                <a class="pilcrow" href="#section-107">&#182;</a>
               </div>
               <p>Compound assignment tokens.</p>
 
@@ -2638,11 +2740,11 @@ TRAILING_SPACES     = <span class="hljs-regexp">/\s+$/</span></pre></div></div>
         </li>
         
         
-        <li id="section-102">
+        <li id="section-108">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-102">&#182;</a>
+                <a class="pilcrow" href="#section-108">&#182;</a>
               </div>
               <p>Unary tokens.</p>
 
@@ -2655,11 +2757,11 @@ UNARY_MATH = [<span class="hljs-string">'!'</span>, <span class="hljs-string">'~
         </li>
         
         
-        <li id="section-103">
+        <li id="section-109">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-103">&#182;</a>
+                <a class="pilcrow" href="#section-109">&#182;</a>
               </div>
               <p>Bit-shifting tokens.</p>
 
@@ -2670,11 +2772,11 @@ UNARY_MATH = [<span class="hljs-string">'!'</span>, <span class="hljs-string">'~
         </li>
         
         
-        <li id="section-104">
+        <li id="section-110">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-104">&#182;</a>
+                <a class="pilcrow" href="#section-110">&#182;</a>
               </div>
               <p>Comparison tokens.</p>
 
@@ -2685,11 +2787,11 @@ UNARY_MATH = [<span class="hljs-string">'!'</span>, <span class="hljs-string">'~
         </li>
         
         
-        <li id="section-105">
+        <li id="section-111">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-105">&#182;</a>
+                <a class="pilcrow" href="#section-111">&#182;</a>
               </div>
               <p>Mathematical tokens.</p>
 
@@ -2700,11 +2802,11 @@ UNARY_MATH = [<span class="hljs-string">'!'</span>, <span class="hljs-string">'~
         </li>
         
         
-        <li id="section-106">
+        <li id="section-112">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-106">&#182;</a>
+                <a class="pilcrow" href="#section-112">&#182;</a>
               </div>
               <p>Relational tokens that are negatable with <code>not</code> prefix.</p>
 
@@ -2715,11 +2817,11 @@ UNARY_MATH = [<span class="hljs-string">'!'</span>, <span class="hljs-string">'~
         </li>
         
         
-        <li id="section-107">
+        <li id="section-113">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-107">&#182;</a>
+                <a class="pilcrow" href="#section-113">&#182;</a>
               </div>
               <p>Boolean tokens.</p>
 
@@ -2730,11 +2832,11 @@ UNARY_MATH = [<span class="hljs-string">'!'</span>, <span class="hljs-string">'~
         </li>
         
         
-        <li id="section-108">
+        <li id="section-114">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-108">&#182;</a>
+                <a class="pilcrow" href="#section-114">&#182;</a>
               </div>
               <p>Tokens which could legitimately be invoked or indexed. An opening
 parentheses or bracket following these tokens will be recorded as the start
@@ -2751,11 +2853,11 @@ INDEXABLE = CALLABLE.concat [
         </li>
         
         
-        <li id="section-109">
+        <li id="section-115">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-109">&#182;</a>
+                <a class="pilcrow" href="#section-115">&#182;</a>
               </div>
               <p>Tokens which can be the left-hand side of a less-than comparison, i.e. <code>a&lt;b</code>.</p>
 
@@ -2766,11 +2868,11 @@ INDEXABLE = CALLABLE.concat [
         </li>
         
         
-        <li id="section-110">
+        <li id="section-116">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-110">&#182;</a>
+                <a class="pilcrow" href="#section-116">&#182;</a>
               </div>
               <p>Tokens which a regular expression will never immediately follow (except spaced
 CALLABLEs in some cases), but which a division operator can.</p>
@@ -2783,11 +2885,11 @@ CALLABLEs in some cases), but which a division operator can.</p>
         </li>
         
         
-        <li id="section-111">
+        <li id="section-117">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-111">&#182;</a>
+                <a class="pilcrow" href="#section-117">&#182;</a>
               </div>
               <p>Tokens that, when immediately preceding a <code>WHEN</code>, indicate that the <code>WHEN</code>
 occurs at the start of a line. We disambiguate these from trailing whens to
@@ -2800,11 +2902,11 @@ avoid an ambiguity in the grammar.</p>
         </li>
         
         
-        <li id="section-112">
+        <li id="section-118">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-112">&#182;</a>
+                <a class="pilcrow" href="#section-118">&#182;</a>
               </div>
               <p>Additional indent in front of these is ignored.</p>
 
@@ -2815,11 +2917,11 @@ avoid an ambiguity in the grammar.</p>
         </li>
         
         
-        <li id="section-113">
+        <li id="section-119">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-113">&#182;</a>
+                <a class="pilcrow" href="#section-119">&#182;</a>
               </div>
               <p>Tokens that, when appearing at the end of a line, suppress a following TERMINATOR/INDENT token</p>
 
@@ -2827,7 +2929,7 @@ avoid an ambiguity in the grammar.</p>
             
             <div class="content"><div class='highlight'><pre>UNFINISHED = [<span class="hljs-string">'\\'</span>, <span class="hljs-string">'.'</span>, <span class="hljs-string">'?.'</span>, <span class="hljs-string">'?::'</span>, <span class="hljs-string">'UNARY'</span>, <span class="hljs-string">'MATH'</span>, <span class="hljs-string">'UNARY_MATH'</span>, <span class="hljs-string">'+'</span>, <span class="hljs-string">'-'</span>,
            <span class="hljs-string">'**'</span>, <span class="hljs-string">'SHIFT'</span>, <span class="hljs-string">'RELATION'</span>, <span class="hljs-string">'COMPARE'</span>, <span class="hljs-string">'&amp;'</span>, <span class="hljs-string">'^'</span>, <span class="hljs-string">'|'</span>, <span class="hljs-string">'&amp;&amp;'</span>, <span class="hljs-string">'||'</span>,
-           <span class="hljs-string">'BIN?'</span>, <span class="hljs-string">'EXTENDS'</span>, <span class="hljs-string">'DEFAULT'</span>]</pre></div></div>
+           <span class="hljs-string">'BIN?'</span>, <span class="hljs-string">'EXTENDS'</span>]</pre></div></div>
             
         </li>
         

docs/v2/annotated-source/repl.html

@@ -224,11 +224,17 @@ Unwrap that too.</p>
               <div class="pilwrap ">
                 <a class="pilcrow" href="#section-7">&#182;</a>
               </div>
-              <p>Collect referenced variable names just like in <code>CoffeeScript.compile</code>.</p>
+              <p>Filter out tokens generated just to hold comments.</p>
 
             </div>
             
-            <div class="content"><div class='highlight'><pre>      referencedVars = (token[<span class="hljs-number">1</span>] <span class="hljs-keyword">for</span> token <span class="hljs-keyword">in</span> tokens <span class="hljs-keyword">when</span> token[<span class="hljs-number">0</span>] <span class="hljs-keyword">is</span> <span class="hljs-string">'IDENTIFIER'</span>)</pre></div></div>
+            <div class="content"><div class='highlight'><pre>      <span class="hljs-keyword">if</span> tokens.length &gt;= <span class="hljs-number">2</span> <span class="hljs-keyword">and</span> tokens[<span class="hljs-number">0</span>].generated <span class="hljs-keyword">and</span>
+         tokens[<span class="hljs-number">0</span>].comments?.length <span class="hljs-keyword">isnt</span> <span class="hljs-number">0</span> <span class="hljs-keyword">and</span> tokens[<span class="hljs-number">0</span>][<span class="hljs-number">1</span>] <span class="hljs-keyword">is</span> <span class="hljs-string">''</span> <span class="hljs-keyword">and</span>
+         tokens[<span class="hljs-number">1</span>][<span class="hljs-number">0</span>] <span class="hljs-keyword">is</span> <span class="hljs-string">'TERMINATOR'</span>
+        tokens = tokens[<span class="hljs-number">2.</span>..]
+      <span class="hljs-keyword">if</span> tokens.length &gt;= <span class="hljs-number">1</span> <span class="hljs-keyword">and</span> tokens[tokens.length - <span class="hljs-number">1</span>].generated <span class="hljs-keyword">and</span>
+         tokens[tokens.length - <span class="hljs-number">1</span>].comments?.length <span class="hljs-keyword">isnt</span> <span class="hljs-number">0</span> <span class="hljs-keyword">and</span> tokens[tokens.length - <span class="hljs-number">1</span>][<span class="hljs-number">1</span>] <span class="hljs-keyword">is</span> <span class="hljs-string">''</span>
+        tokens.pop()</pre></div></div>
             
         </li>
         
@@ -239,11 +245,11 @@ Unwrap that too.</p>
               <div class="pilwrap ">
                 <a class="pilcrow" href="#section-8">&#182;</a>
               </div>
-              <p>Generate the AST of the tokens.</p>
+              <p>Collect referenced variable names just like in <code>CoffeeScript.compile</code>.</p>
 
             </div>
             
-            <div class="content"><div class='highlight'><pre>      ast = CoffeeScript.nodes tokens</pre></div></div>
+            <div class="content"><div class='highlight'><pre>      referencedVars = (token[<span class="hljs-number">1</span>] <span class="hljs-keyword">for</span> token <span class="hljs-keyword">in</span> tokens <span class="hljs-keyword">when</span> token[<span class="hljs-number">0</span>] <span class="hljs-keyword">is</span> <span class="hljs-string">'IDENTIFIER'</span>)</pre></div></div>
             
         </li>
         
@@ -254,11 +260,11 @@ Unwrap that too.</p>
               <div class="pilwrap ">
                 <a class="pilcrow" href="#section-9">&#182;</a>
               </div>
-              <p>Add assignment to <code>__</code> variable to force the input to be an expression.</p>
+              <p>Generate the AST of the tokens.</p>
 
             </div>
             
-            <div class="content"><div class='highlight'><pre>      ast = <span class="hljs-keyword">new</span> Block [<span class="hljs-keyword">new</span> Assign (<span class="hljs-keyword">new</span> Value <span class="hljs-keyword">new</span> Literal <span class="hljs-string">'__'</span>), ast, <span class="hljs-string">'='</span>]</pre></div></div>
+            <div class="content"><div class='highlight'><pre>      ast = CoffeeScript.nodes tokens</pre></div></div>
             
         </li>
         
@@ -269,6 +275,21 @@ Unwrap that too.</p>
               <div class="pilwrap ">
                 <a class="pilcrow" href="#section-10">&#182;</a>
               </div>
+              <p>Add assignment to <code>__</code> variable to force the input to be an expression.</p>
+
+            </div>
+            
+            <div class="content"><div class='highlight'><pre>      ast = <span class="hljs-keyword">new</span> Block [<span class="hljs-keyword">new</span> Assign (<span class="hljs-keyword">new</span> Value <span class="hljs-keyword">new</span> Literal <span class="hljs-string">'__'</span>), ast, <span class="hljs-string">'='</span>]</pre></div></div>
+            
+        </li>
+        
+        
+        <li id="section-11">
+            <div class="annotation">
+              
+              <div class="pilwrap ">
+                <a class="pilcrow" href="#section-11">&#182;</a>
+              </div>
               <p>Wrap the expression in a closure to support top-level <code>await</code>.</p>
 
             </div>
@@ -279,11 +300,11 @@ Unwrap that too.</p>
         </li>
         
         
-        <li id="section-11">
+        <li id="section-12">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-11">&#182;</a>
+                <a class="pilcrow" href="#section-12">&#182;</a>
               </div>
               <p>Invoke the wrapping closure.</p>
 
@@ -297,11 +318,11 @@ Unwrap that too.</p>
         </li>
         
         
-        <li id="section-12">
+        <li id="section-13">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-12">&#182;</a>
+                <a class="pilcrow" href="#section-13">&#182;</a>
               </div>
               <p>Strip <code>&quot;use strict&quot;</code>, to avoid an exception on assigning to
 undeclared variable <code>__</code>.</p>
@@ -314,11 +335,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-13">
+        <li id="section-14">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-13">&#182;</a>
+                <a class="pilcrow" href="#section-14">&#182;</a>
               </div>
               <p>Await an async result, if necessary.</p>
 
@@ -335,11 +356,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-14">
+        <li id="section-15">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-14">&#182;</a>
+                <a class="pilcrow" href="#section-15">&#182;</a>
               </div>
               <p>AST’s <code>compile</code> does not add source code information to syntax errors.</p>
 
@@ -360,11 +381,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-15">
+        <li id="section-16">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-15">&#182;</a>
+                <a class="pilcrow" href="#section-16">&#182;</a>
               </div>
               <p>Node 0.11.12 changed API, prompt is now _prompt.</p>
 
@@ -381,11 +402,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-16">
+        <li id="section-17">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-16">&#182;</a>
+                <a class="pilcrow" href="#section-17">&#182;</a>
               </div>
               <p>Proxy node’s line listener</p>
 
@@ -406,11 +427,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-17">
+        <li id="section-18">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-17">&#182;</a>
+                <a class="pilcrow" href="#section-18">&#182;</a>
               </div>
               <p>Handle Ctrl-v</p>
 
@@ -423,11 +444,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-18">
+        <li id="section-19">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-18">&#182;</a>
+                <a class="pilcrow" href="#section-19">&#182;</a>
               </div>
               <p>allow arbitrarily switching between modes any time before multiple lines are entered</p>
 
@@ -442,11 +463,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-19">
+        <li id="section-20">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-19">&#182;</a>
+                <a class="pilcrow" href="#section-20">&#182;</a>
               </div>
               <p>no-op unless the current line is empty</p>
 
@@ -457,11 +478,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-20">
+        <li id="section-21">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-20">&#182;</a>
+                <a class="pilcrow" href="#section-21">&#182;</a>
               </div>
               <p>eval, print, loop</p>
 
@@ -476,11 +497,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-21">
+        <li id="section-22">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-21">&#182;</a>
+                <a class="pilcrow" href="#section-22">&#182;</a>
               </div>
               <p>XXX: multiline hack</p>
 
@@ -498,11 +519,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-22">
+        <li id="section-23">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-22">&#182;</a>
+                <a class="pilcrow" href="#section-23">&#182;</a>
               </div>
               <p>Store and load command history from a file</p>
 
@@ -515,11 +536,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-23">
+        <li id="section-24">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-23">&#182;</a>
+                <a class="pilcrow" href="#section-24">&#182;</a>
               </div>
               <p>Get file info and at most maxSize of command history</p>
 
@@ -531,11 +552,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-24">
+        <li id="section-25">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-24">&#182;</a>
+                <a class="pilcrow" href="#section-25">&#182;</a>
               </div>
               <p>Read last <code>size</code> bytes from the file</p>
 
@@ -549,11 +570,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-25">
+        <li id="section-26">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-25">&#182;</a>
+                <a class="pilcrow" href="#section-26">&#182;</a>
               </div>
               <p>Set the history on the interpreter</p>
 
@@ -564,11 +585,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-26">
+        <li id="section-27">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-26">&#182;</a>
+                <a class="pilcrow" href="#section-27">&#182;</a>
               </div>
               <p>If the history file was truncated we should pop off a potential partial line</p>
 
@@ -579,11 +600,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-27">
+        <li id="section-28">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-27">&#182;</a>
+                <a class="pilcrow" href="#section-28">&#182;</a>
               </div>
               <p>Shift off the final blank newline</p>
 
@@ -601,11 +622,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-28">
+        <li id="section-29">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-28">&#182;</a>
+                <a class="pilcrow" href="#section-29">&#182;</a>
               </div>
               <p>Save the latest command in the file</p>
 
@@ -617,11 +638,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-29">
+        <li id="section-30">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-29">&#182;</a>
+                <a class="pilcrow" href="#section-30">&#182;</a>
               </div>
               <p>XXX: The SIGINT event from REPLServer is undocumented, so this is a bit fragile</p>
 
@@ -633,11 +654,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-30">
+        <li id="section-31">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-30">&#182;</a>
+                <a class="pilcrow" href="#section-31">&#182;</a>
               </div>
               <p>Add a command to show the history stack</p>
 
@@ -654,11 +675,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-31">
+        <li id="section-32">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-31">&#182;</a>
+                <a class="pilcrow" href="#section-32">&#182;</a>
               </div>
               <p>Node 0.11 changed API, a command such as ‘.help’ is now stored as ‘help’</p>
 
@@ -697,11 +718,11 @@ undeclared variable <code>__</code>.</p>
         </li>
         
         
-        <li id="section-32">
+        <li id="section-33">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-32">&#182;</a>
+                <a class="pilcrow" href="#section-33">&#182;</a>
               </div>
               <p>Since the REPL compilation path is unique (in <code>eval</code> above), we need
 another way to get the <code>options</code> object attached to a module so that
@@ -725,11 +746,11 @@ the REPL, the only applicable option is <code>transpile</code>.</p>
         </li>
         
         
-        <li id="section-33">
+        <li id="section-34">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-33">&#182;</a>
+                <a class="pilcrow" href="#section-34">&#182;</a>
               </div>
               <p>Adapt help inherited from the node REPL</p>
 

docs/v2/annotated-source/rewriter.html

@@ -676,7 +676,21 @@ class declaration or if-conditionals).</p>
             endImplicitObject()
           <span class="hljs-keyword">else</span>
             stack.pop()
-        start = stack.pop()</pre></div></div>
+        start = stack.pop()
+<span class="hljs-function">
+      <span class="hljs-title">inControlFlow</span> = =&gt;</span>
+        seenFor = @findTagsBackwards(i, [<span class="hljs-string">'FOR'</span>]) <span class="hljs-keyword">and</span> @findTagsBackwards(i, [<span class="hljs-string">'FORIN'</span>, <span class="hljs-string">'FOROF'</span>, <span class="hljs-string">'FORFROM'</span>])
+        controlFlow = seenFor <span class="hljs-keyword">or</span> @findTagsBackwards i, [<span class="hljs-string">'WHILE'</span>, <span class="hljs-string">'UNTIL'</span>, <span class="hljs-string">'LOOP'</span>, <span class="hljs-string">'LEADING_WHEN'</span>]
+        <span class="hljs-keyword">return</span> <span class="hljs-literal">no</span> <span class="hljs-keyword">unless</span> controlFlow
+        isFunc = <span class="hljs-literal">no</span>
+        tagCurrentLine = token[<span class="hljs-number">2</span>].first_line
+        @detectEnd i,
+          <span class="hljs-function"><span class="hljs-params">(token, i)</span> -&gt;</span> token[<span class="hljs-number">0</span>] <span class="hljs-keyword">in</span> LINEBREAKS
+          (token, i) -&gt;
+            [prevTag, ,{first_line}] = tokens[i - <span class="hljs-number">1</span>] || []
+            isFunc = tagCurrentLine <span class="hljs-keyword">is</span> first_line <span class="hljs-keyword">and</span> prevTag <span class="hljs-keyword">in</span> [<span class="hljs-string">'-&gt;'</span>, <span class="hljs-string">'=&gt;'</span>]
+          returnOnNegativeLevel: <span class="hljs-literal">yes</span>
+        isFunc</pre></div></div>
             
         </li>
         
@@ -698,7 +712,8 @@ Added support for spread dots on the left side: f …a</p>
          (nextTag <span class="hljs-keyword">in</span> IMPLICIT_CALL <span class="hljs-keyword">or</span>
          (nextTag <span class="hljs-keyword">is</span> <span class="hljs-string">'...'</span> <span class="hljs-keyword">and</span> @tag(i + <span class="hljs-number">2</span>) <span class="hljs-keyword">in</span> IMPLICIT_CALL <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> @findTagsBackwards(i, [<span class="hljs-string">'INDEX_START'</span>, <span class="hljs-string">'['</span>])) <span class="hljs-keyword">or</span>
           nextTag <span class="hljs-keyword">in</span> IMPLICIT_UNSPACED_CALL <span class="hljs-keyword">and</span>
-          <span class="hljs-keyword">not</span> nextToken.spaced <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> nextToken.newLine)
+          <span class="hljs-keyword">not</span> nextToken.spaced <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> nextToken.newLine) <span class="hljs-keyword">and</span>
+          <span class="hljs-keyword">not</span> inControlFlow()
         tag = token[<span class="hljs-number">0</span>] = <span class="hljs-string">'FUNC_EXIST'</span> <span class="hljs-keyword">if</span> tag <span class="hljs-keyword">is</span> <span class="hljs-string">'?'</span>
         startImplicitCall i + <span class="hljs-number">1</span>
         <span class="hljs-keyword">return</span> forward(<span class="hljs-number">2</span>)</pre></div></div>
@@ -835,7 +850,9 @@ like e.g.:</p>
           stackItem[<span class="hljs-number">2</span>].sameLine = <span class="hljs-literal">no</span> <span class="hljs-keyword">if</span> isImplicitObject stackItem
 
       newLine = prevTag <span class="hljs-keyword">is</span> <span class="hljs-string">'OUTDENT'</span> <span class="hljs-keyword">or</span> prevToken.newLine
-      <span class="hljs-keyword">if</span> tag <span class="hljs-keyword">in</span> IMPLICIT_END <span class="hljs-keyword">or</span> tag <span class="hljs-keyword">in</span> CALL_CLOSERS <span class="hljs-keyword">and</span> newLine
+      <span class="hljs-keyword">if</span> tag <span class="hljs-keyword">in</span> IMPLICIT_END <span class="hljs-keyword">or</span>
+          (tag <span class="hljs-keyword">in</span> CALL_CLOSERS <span class="hljs-keyword">and</span> newLine) <span class="hljs-keyword">or</span>
+          (tag <span class="hljs-keyword">in</span> [<span class="hljs-string">'..'</span>, <span class="hljs-string">'...'</span>] <span class="hljs-keyword">and</span> @findTagsBackwards(i, [<span class="hljs-string">"INDEX_START"</span>]))
         <span class="hljs-keyword">while</span> inImplicit()
           [stackTag, stackIdx, {sameLine, startsLine}] = stackTop()</pre></div></div>
             
@@ -852,7 +869,8 @@ like e.g.:</p>
 
             </div>
             
-            <div class="content"><div class='highlight'><pre>          <span class="hljs-keyword">if</span> inImplicitCall() <span class="hljs-keyword">and</span> prevTag <span class="hljs-keyword">isnt</span> <span class="hljs-string">','</span>
+            <div class="content"><div class='highlight'><pre>          <span class="hljs-keyword">if</span> inImplicitCall() <span class="hljs-keyword">and</span> prevTag <span class="hljs-keyword">isnt</span> <span class="hljs-string">','</span> <span class="hljs-keyword">or</span>
+              (prevTag <span class="hljs-keyword">is</span> <span class="hljs-string">','</span> <span class="hljs-keyword">and</span> tag <span class="hljs-keyword">is</span> <span class="hljs-string">'TERMINATOR'</span> <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> nextTag?)
             endImplicitCall()</pre></div></div>
             
         </li>
@@ -916,7 +934,7 @@ e = <span class="hljs-number">2</span>
 </code></pre>
             </div>
             
-            <div class="content"><div class='highlight'><pre>      <span class="hljs-keyword">if</span> tag <span class="hljs-keyword">is</span> <span class="hljs-string">','</span> <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> @looksObjectish(i + <span class="hljs-number">1</span>) <span class="hljs-keyword">and</span> inImplicitObject() <span class="hljs-keyword">and</span>
+            <div class="content"><div class='highlight'><pre>      <span class="hljs-keyword">if</span> tag <span class="hljs-keyword">is</span> <span class="hljs-string">','</span> <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> @looksObjectish(i + <span class="hljs-number">1</span>) <span class="hljs-keyword">and</span> inImplicitObject() <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> (@tag(i + <span class="hljs-number">2</span>) <span class="hljs-keyword">in</span> [<span class="hljs-string">'FOROF'</span>, <span class="hljs-string">'FORIN'</span>]) <span class="hljs-keyword">and</span>
          (nextTag <span class="hljs-keyword">isnt</span> <span class="hljs-string">'TERMINATOR'</span> <span class="hljs-keyword">or</span> <span class="hljs-keyword">not</span> @looksObjectish(i + <span class="hljs-number">2</span>))</pre></div></div>
             
         </li>
@@ -1245,20 +1263,101 @@ blocks are added.</p>
             
             <div class="content"><div class='highlight'><pre>  normalizeLines: <span class="hljs-function">-&gt;</span>
     starter = indent = outdent = <span class="hljs-literal">null</span>
+    leading_switch_when = <span class="hljs-literal">null</span>
+    leading_if_then = <span class="hljs-literal">null</span></pre></div></div>
+            
+        </li>
+        
+        
+        <li id="section-50">
+            <div class="annotation">
+              
+              <div class="pilwrap ">
+                <a class="pilcrow" href="#section-50">&#182;</a>
+              </div>
+              <p>Count <code>THEN</code> tags</p>
+
+            </div>
+            
+            <div class="content"><div class='highlight'><pre>    ifThens = []
 <span class="hljs-function">
     <span class="hljs-title">condition</span> = <span class="hljs-params">(token, i)</span> -&gt;</span>
       token[<span class="hljs-number">1</span>] <span class="hljs-keyword">isnt</span> <span class="hljs-string">';'</span> <span class="hljs-keyword">and</span> token[<span class="hljs-number">0</span>] <span class="hljs-keyword">in</span> SINGLE_CLOSERS <span class="hljs-keyword">and</span>
       <span class="hljs-keyword">not</span> (token[<span class="hljs-number">0</span>] <span class="hljs-keyword">is</span> <span class="hljs-string">'TERMINATOR'</span> <span class="hljs-keyword">and</span> @tag(i + <span class="hljs-number">1</span>) <span class="hljs-keyword">in</span> EXPRESSION_CLOSE) <span class="hljs-keyword">and</span>
-      <span class="hljs-keyword">not</span> (token[<span class="hljs-number">0</span>] <span class="hljs-keyword">is</span> <span class="hljs-string">'ELSE'</span> <span class="hljs-keyword">and</span> starter <span class="hljs-keyword">isnt</span> <span class="hljs-string">'THEN'</span>) <span class="hljs-keyword">and</span>
+      <span class="hljs-keyword">not</span> (token[<span class="hljs-number">0</span>] <span class="hljs-keyword">is</span> <span class="hljs-string">'ELSE'</span> <span class="hljs-keyword">and</span>
+           (starter <span class="hljs-keyword">isnt</span> <span class="hljs-string">'THEN'</span> <span class="hljs-keyword">or</span> (leading_if_then <span class="hljs-keyword">or</span> leading_switch_when))) <span class="hljs-keyword">and</span>
       <span class="hljs-keyword">not</span> (token[<span class="hljs-number">0</span>] <span class="hljs-keyword">in</span> [<span class="hljs-string">'CATCH'</span>, <span class="hljs-string">'FINALLY'</span>] <span class="hljs-keyword">and</span> starter <span class="hljs-keyword">in</span> [<span class="hljs-string">'-&gt;'</span>, <span class="hljs-string">'=&gt;'</span>]) <span class="hljs-keyword">or</span>
       token[<span class="hljs-number">0</span>] <span class="hljs-keyword">in</span> CALL_CLOSERS <span class="hljs-keyword">and</span>
       (@tokens[i - <span class="hljs-number">1</span>].newLine <span class="hljs-keyword">or</span> @tokens[i - <span class="hljs-number">1</span>][<span class="hljs-number">0</span>] <span class="hljs-keyword">is</span> <span class="hljs-string">'OUTDENT'</span>)
 <span class="hljs-function">
     <span class="hljs-title">action</span> = <span class="hljs-params">(token, i)</span> -&gt;</span>
+      ifThens.pop() <span class="hljs-keyword">if</span> token[<span class="hljs-number">0</span>] <span class="hljs-keyword">is</span> <span class="hljs-string">'ELSE'</span> <span class="hljs-keyword">and</span> starter <span class="hljs-keyword">is</span> <span class="hljs-string">'THEN'</span>
       @tokens.splice (<span class="hljs-keyword">if</span> @tag(i - <span class="hljs-number">1</span>) <span class="hljs-keyword">is</span> <span class="hljs-string">','</span> <span class="hljs-keyword">then</span> i - <span class="hljs-number">1</span> <span class="hljs-keyword">else</span> i), <span class="hljs-number">0</span>, outdent
+<span class="hljs-function">
+    <span class="hljs-title">closeElseTag</span> = <span class="hljs-params">(tokens, i)</span> =&gt;</span>
+      tlen = ifThens.length
+      <span class="hljs-keyword">return</span> i <span class="hljs-keyword">unless</span> tlen &gt; <span class="hljs-number">0</span>
+      lastThen = ifThens.pop()
+      [, outdentElse] = @indentation tokens[lastThen]</pre></div></div>
+            
+        </li>
+        
+        
+        <li id="section-51">
+            <div class="annotation">
+              
+              <div class="pilwrap ">
+                <a class="pilcrow" href="#section-51">&#182;</a>
+              </div>
+              <p>Insert <code>OUTDENT</code> to close inner <code>IF</code>.</p>
+
+            </div>
+            
+            <div class="content"><div class='highlight'><pre>      outdentElse[<span class="hljs-number">1</span>] = tlen*<span class="hljs-number">2</span>
+      tokens.splice(i, <span class="hljs-number">0</span>, outdentElse)</pre></div></div>
+            
+        </li>
+        
+        
+        <li id="section-52">
+            <div class="annotation">
+              
+              <div class="pilwrap ">
+                <a class="pilcrow" href="#section-52">&#182;</a>
+              </div>
+              <p>Insert <code>OUTDENT</code> to close outer <code>IF</code>.</p>
+
+            </div>
+            
+            <div class="content"><div class='highlight'><pre>      outdentElse[<span class="hljs-number">1</span>] = <span class="hljs-number">2</span>
+      tokens.splice(i + <span class="hljs-number">1</span>, <span class="hljs-number">0</span>, outdentElse)</pre></div></div>
+            
+        </li>
+        
+        
+        <li id="section-53">
+            <div class="annotation">
+              
+              <div class="pilwrap ">
+                <a class="pilcrow" href="#section-53">&#182;</a>
+              </div>
+              <p>Remove outdents from the end.</p>
+
+            </div>
+            
+            <div class="content"><div class='highlight'><pre>      @detectEnd i + <span class="hljs-number">2</span>,
+        <span class="hljs-function"><span class="hljs-params">(token, i)</span> -&gt;</span> token[<span class="hljs-number">0</span>] <span class="hljs-keyword">in</span> [<span class="hljs-string">'OUTDENT'</span>, <span class="hljs-string">'TERMINATOR'</span>]
+        (token, i) -&gt;
+            <span class="hljs-keyword">if</span> @tag(i) <span class="hljs-keyword">is</span> <span class="hljs-string">'OUTDENT'</span> <span class="hljs-keyword">and</span> @tag(i + <span class="hljs-number">1</span>) <span class="hljs-keyword">is</span> <span class="hljs-string">'OUTDENT'</span>
+              tokens.splice i, <span class="hljs-number">2</span>
+      i + <span class="hljs-number">2</span>
 
     @scanTokens (token, i, tokens) -&gt;
       [tag] = token
+      conditionTag = tag <span class="hljs-keyword">in</span> [<span class="hljs-string">'-&gt;'</span>, <span class="hljs-string">'=&gt;'</span>] <span class="hljs-keyword">and</span>
+        @findTagsBackwards(i, [<span class="hljs-string">'IF'</span>, <span class="hljs-string">'WHILE'</span>, <span class="hljs-string">'FOR'</span>, <span class="hljs-string">'UNTIL'</span>, <span class="hljs-string">'SWITCH'</span>, <span class="hljs-string">'WHEN'</span>, <span class="hljs-string">'LEADING_WHEN'</span>, <span class="hljs-string">'['</span>, <span class="hljs-string">'INDEX_START'</span>]) <span class="hljs-keyword">and</span>
+        <span class="hljs-keyword">not</span> (@findTagsBackwards i, [<span class="hljs-string">'THEN'</span>, <span class="hljs-string">'..'</span>, <span class="hljs-string">'...'</span>])
+
       <span class="hljs-keyword">if</span> tag <span class="hljs-keyword">is</span> <span class="hljs-string">'TERMINATOR'</span>
         <span class="hljs-keyword">if</span> @tag(i + <span class="hljs-number">1</span>) <span class="hljs-keyword">is</span> <span class="hljs-string">'ELSE'</span> <span class="hljs-keyword">and</span> @tag(i - <span class="hljs-number">1</span>) <span class="hljs-keyword">isnt</span> <span class="hljs-string">'OUTDENT'</span>
           tokens.splice i, <span class="hljs-number">1</span>, @indentation()...
@@ -1275,10 +1374,31 @@ blocks are added.</p>
         tokens.splice i + <span class="hljs-number">1</span>, <span class="hljs-number">0</span>, indent, outdent
         <span class="hljs-keyword">return</span> <span class="hljs-number">1</span>
       <span class="hljs-keyword">if</span> tag <span class="hljs-keyword">in</span> SINGLE_LINERS <span class="hljs-keyword">and</span> @tag(i + <span class="hljs-number">1</span>) <span class="hljs-keyword">isnt</span> <span class="hljs-string">'INDENT'</span> <span class="hljs-keyword">and</span>
-         <span class="hljs-keyword">not</span> (tag <span class="hljs-keyword">is</span> <span class="hljs-string">'ELSE'</span> <span class="hljs-keyword">and</span> @tag(i + <span class="hljs-number">1</span>) <span class="hljs-keyword">is</span> <span class="hljs-string">'IF'</span>)
+         <span class="hljs-keyword">not</span> (tag <span class="hljs-keyword">is</span> <span class="hljs-string">'ELSE'</span> <span class="hljs-keyword">and</span> @tag(i + <span class="hljs-number">1</span>) <span class="hljs-keyword">is</span> <span class="hljs-string">'IF'</span>) <span class="hljs-keyword">and</span>
+         <span class="hljs-keyword">not</span> conditionTag
         starter = tag
         [indent, outdent] = @indentation tokens[i]
         indent.fromThen   = <span class="hljs-literal">true</span> <span class="hljs-keyword">if</span> starter <span class="hljs-keyword">is</span> <span class="hljs-string">'THEN'</span>
+        <span class="hljs-keyword">if</span> tag <span class="hljs-keyword">is</span> <span class="hljs-string">'THEN'</span>
+          leading_switch_when = @findTagsBackwards(i, [<span class="hljs-string">'LEADING_WHEN'</span>]) <span class="hljs-keyword">and</span> @tag(i + <span class="hljs-number">1</span>) <span class="hljs-keyword">is</span> <span class="hljs-string">'IF'</span>
+          leading_if_then = @findTagsBackwards(i, [<span class="hljs-string">'IF'</span>]) <span class="hljs-keyword">and</span> @tag(i + <span class="hljs-number">1</span>) <span class="hljs-keyword">is</span> <span class="hljs-string">'IF'</span>
+        ifThens.push i <span class="hljs-keyword">if</span> tag <span class="hljs-keyword">is</span> <span class="hljs-string">'THEN'</span> <span class="hljs-keyword">and</span> @findTagsBackwards(i, [<span class="hljs-string">'IF'</span>])</pre></div></div>
+            
+        </li>
+        
+        
+        <li id="section-54">
+            <div class="annotation">
+              
+              <div class="pilwrap ">
+                <a class="pilcrow" href="#section-54">&#182;</a>
+              </div>
+              <p><code>ELSE</code> tag is not closed.</p>
+
+            </div>
+            
+            <div class="content"><div class='highlight'><pre>        <span class="hljs-keyword">if</span> tag <span class="hljs-keyword">is</span> <span class="hljs-string">'ELSE'</span> <span class="hljs-keyword">and</span> @tag(i - <span class="hljs-number">1</span>) <span class="hljs-keyword">isnt</span> <span class="hljs-string">'OUTDENT'</span>
+          i = closeElseTag tokens, i
         tokens.splice i + <span class="hljs-number">1</span>, <span class="hljs-number">0</span>, indent
         @detectEnd i + <span class="hljs-number">2</span>, condition, action
         tokens.splice i, <span class="hljs-number">1</span> <span class="hljs-keyword">if</span> tag <span class="hljs-keyword">is</span> <span class="hljs-string">'THEN'</span>
@@ -1288,11 +1408,11 @@ blocks are added.</p>
         </li>
         
         
-        <li id="section-50">
+        <li id="section-55">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-50">&#182;</a>
+                <a class="pilcrow" href="#section-55">&#182;</a>
               </div>
               <p>Tag postfix conditionals as such, so that we can parse them with a
 different precedence.</p>
@@ -1320,11 +1440,11 @@ different precedence.</p>
         </li>
         
         
-        <li id="section-51">
+        <li id="section-56">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-51">&#182;</a>
+                <a class="pilcrow" href="#section-56">&#182;</a>
               </div>
               <p>Generate the indentation tokens, based on another token on the same line.</p>
 
@@ -1345,11 +1465,11 @@ different precedence.</p>
         </li>
         
         
-        <li id="section-52">
+        <li id="section-57">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-52">&#182;</a>
+                <a class="pilcrow" href="#section-57">&#182;</a>
               </div>
               <p>Look up a tag by token index.</p>
 
@@ -1360,11 +1480,11 @@ different precedence.</p>
         </li>
         
         
-        <li id="section-53">
+        <li id="section-58">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-53">&#182;</a>
+                <a class="pilcrow" href="#section-58">&#182;</a>
               </div>
               <h2 id="constants">Constants</h2>
 
@@ -1373,11 +1493,11 @@ different precedence.</p>
         </li>
         
         
-        <li id="section-54">
+        <li id="section-59">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-54">&#182;</a>
+                <a class="pilcrow" href="#section-59">&#182;</a>
               </div>
               
             </div>
@@ -1385,11 +1505,11 @@ different precedence.</p>
         </li>
         
         
-        <li id="section-55">
+        <li id="section-60">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-55">&#182;</a>
+                <a class="pilcrow" href="#section-60">&#182;</a>
               </div>
               <p>List of the token pairs that must be balanced.</p>
 
@@ -1410,11 +1530,11 @@ different precedence.</p>
         </li>
         
         
-        <li id="section-56">
+        <li id="section-61">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-56">&#182;</a>
+                <a class="pilcrow" href="#section-61">&#182;</a>
               </div>
               <p>The inverse mappings of <code>BALANCED_PAIRS</code> we’re trying to fix up, so we can
 look things up from either end.</p>
@@ -1426,11 +1546,11 @@ look things up from either end.</p>
         </li>
         
         
-        <li id="section-57">
+        <li id="section-62">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-57">&#182;</a>
+                <a class="pilcrow" href="#section-62">&#182;</a>
               </div>
               <p>The tokens that signal the start/end of a balanced pair.</p>
 
@@ -1446,11 +1566,11 @@ EXPRESSION_END   = []
         </li>
         
         
-        <li id="section-58">
+        <li id="section-63">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-58">&#182;</a>
+                <a class="pilcrow" href="#section-63">&#182;</a>
               </div>
               <p>Tokens that indicate the close of a clause of an expression.</p>
 
@@ -1461,11 +1581,11 @@ EXPRESSION_END   = []
         </li>
         
         
-        <li id="section-59">
+        <li id="section-64">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-59">&#182;</a>
+                <a class="pilcrow" href="#section-64">&#182;</a>
               </div>
               <p>Tokens that, if followed by an <code>IMPLICIT_CALL</code>, indicate a function invocation.</p>
 
@@ -1476,11 +1596,11 @@ EXPRESSION_END   = []
         </li>
         
         
-        <li id="section-60">
+        <li id="section-65">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-60">&#182;</a>
+                <a class="pilcrow" href="#section-65">&#182;</a>
               </div>
               <p>If preceded by an <code>IMPLICIT_FUNC</code>, indicates a function invocation.</p>
 
@@ -1500,11 +1620,11 @@ IMPLICIT_UNSPACED_CALL = [<span class="hljs-string">'+'</span>, <span class="hlj
         </li>
         
         
-        <li id="section-61">
+        <li id="section-66">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-61">&#182;</a>
+                <a class="pilcrow" href="#section-66">&#182;</a>
               </div>
               <p>Tokens that always mark the end of an implicit call for single-liners.</p>
 
@@ -1516,11 +1636,11 @@ IMPLICIT_UNSPACED_CALL = [<span class="hljs-string">'+'</span>, <span class="hlj
         </li>
         
         
-        <li id="section-62">
+        <li id="section-67">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-62">&#182;</a>
+                <a class="pilcrow" href="#section-67">&#182;</a>
               </div>
               <p>Single-line flavors of block expressions that have unclosed endings.
 The grammar can’t disambiguate them, so we insert the implicit indentation.</p>
@@ -1533,11 +1653,11 @@ SINGLE_CLOSERS   = [<span class="hljs-string">'TERMINATOR'</span>, <span class="
         </li>
         
         
-        <li id="section-63">
+        <li id="section-68">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-63">&#182;</a>
+                <a class="pilcrow" href="#section-68">&#182;</a>
               </div>
               <p>Tokens that end a line.</p>
 
@@ -1548,11 +1668,11 @@ SINGLE_CLOSERS   = [<span class="hljs-string">'TERMINATOR'</span>, <span class="
         </li>
         
         
-        <li id="section-64">
+        <li id="section-69">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-64">&#182;</a>
+                <a class="pilcrow" href="#section-69">&#182;</a>
               </div>
               <p>Tokens that close open calls when they follow a newline.</p>
 
@@ -1563,11 +1683,11 @@ SINGLE_CLOSERS   = [<span class="hljs-string">'TERMINATOR'</span>, <span class="
         </li>
         
         
-        <li id="section-65">
+        <li id="section-70">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-65">&#182;</a>
+                <a class="pilcrow" href="#section-70">&#182;</a>
               </div>
               <p>Tokens that prevent a subsequent indent from ending implicit calls/objects</p>
 
@@ -1578,11 +1698,11 @@ SINGLE_CLOSERS   = [<span class="hljs-string">'TERMINATOR'</span>, <span class="
         </li>
         
         
-        <li id="section-66">
+        <li id="section-71">
             <div class="annotation">
               
               <div class="pilwrap ">
-                <a class="pilcrow" href="#section-66">&#182;</a>
+                <a class="pilcrow" href="#section-71">&#182;</a>
               </div>
               <p>Tokens that are swallowed up by the parser, never leading to code generation.
 You can spot these in <code>grammar.coffee</code> because the <code>o</code> function second

documentation/examples/get_set.coffee

@@ -6,4 +6,4 @@ Object.defineProperty screen, 'height',
   get: ->
     this.width / this.ratio
   set: (val) ->
-    this.width = val / this.ratio
+    this.width = val * this.ratio

documentation/sections/changelog.md

@@ -1,5 +1,88 @@
 ## Changelog
 
+```
+releaseHeader('2018-04-29', '2.3.0', '2.2.4')
+```
+*   This release adds support for all the new features and syntaxes in ES2018 that weren’t already possible in CoffeeScript. For all of the below features, make sure that you [transpile](#transpilation) unless you know that your target runtime(s) support each feature.
+*   Asynchronous iterators are now supported. You can now `yield` an `await` call, e.g. `do -> until file.EOF then yield await file.readLine()`. 
+*   Object splats/destructuring, a.k.a. object rest/spread syntax, has been standardized as part of ES2018 and therefore this release removes the polyfill that had previously been supporting this syntax. Code like `{a, b, rest...} = obj` now outputs more or less just like it appears, rather than being converted into an `Object.assign` call. Note that there are [some subtle differences](https://developers.google.com/web/updates/2017/06/object-rest-spread) between the `Object.assign` polyfill and the native implementation.
+*   The exponentiation operator, `**`, and exponentiation assignment operator `**=` are new to JavaScript in ES2018. Now code like `a ** 3` is output as it appears, rather than being converted into `Math.pow(a, 3)` as it was before.
+*   The `s` (dotAll) flag is now supported in regular expressions.
+
+```
+releaseHeader('2018-03-29', '2.2.4', '2.2.3')
+```
+*   When the `by` value in a `for` loop is a literal number, e.g. `for x in [2..1] by -1`, fewer checks are necessary to determine if the loop is in range.
+*   Bugfix for regression in 2.2.0 where a statement inside parentheses, e.g. `(fn(); break) while condition`, was compiling. Pure statements like `break` or `return` cannot turn a parenthesized block into an expression, and should throw an error.
+
+```
+releaseHeader('2018-03-11', '2.2.3', '2.2.2')
+```
+*   Bugfix for object destructuring with an empty array as a key’s value: `{ key: [] } = obj`.
+*   Bugfix for array destructuring onto targets attached to `this`: `[ @most... , @penultimate, @last ] = arr`.
+
+```
+releaseHeader('2018-02-21', '2.2.2', '2.2.1')
+```
+*   Bugfix for regression in 2.2.0 where a range with a `by` (step) value that increments or decrements in the opposite direction as the range was returning an array containing the first value of the range, whereas it should be returning an empty array. In other words, `x for x in [2..1] by 1` should equal `[]`, not `[2]` (because the step value is positive 1, counting up, whereas the range goes from 2 to 1, counting down).
+*   Bugfixes for allowing backslashes in `import` and `export` statements and lines that trigger the start of an indented block, like an `if` statement.
+
+```
+releaseHeader('2018-02-06', '2.2.1', '2.2.0')
+```
+*   Bugfix for regression in 2.2.0 involving an error thrown by the compiler in certain cases when using destructuring with a splat or expansion in an array.
+*   Bugfix for regression in 2.2.0 where in certain cases a range iterator variable was declared in the global scope.
+
+```
+releaseHeader('2018-02-01', '2.2.0', '2.1.1')
+```
+*   This release fixes *all* currently open bugs, dating as far back as 2014, 2012 and 2011.
+*   **Potential breaking change:** An inline `if` or `switch` statement with an ambiguous `else`, such as `if no then if yes then alert 1 else alert 2`, now compiles where the `else` always corresponds to the closest open `then`. Previously the behavior of an ambiguous `else` was unpredictable. If your code has any `if … then` or `switch … then` statements with multiple `then`s (and one or more `else`s) the compiled output might be different now, unless you had resolved ambiguity via parentheses. We made this change because the previous behavior was inconsistent and basically a bug: depending on what grammar was where, for example if there was an inline function or something that implied a block, the `else` might bind to an earlier `then` rather than a later `then`. Now an `else` essentially closes a block opened by a `then`, similar to closing an open parenthesis.
+*   When a required `then` is missing, the error more accurately points out the location of the mistake.
+*   An error is thrown when the `coffee` command is run in an environment that doesn’t support some ES2015 JavaScript features that the CoffeeScript compiler itself requires. This can happen if CoffeeScript is installed in Node older than version 6.
+*   Destructuring with a non-final splat/spread, e.g. `[open, contents..., close] = tag.split('')` is now output using ES2015 rest syntax.
+*   Functions named `get` or `set` can be used without parentheses in more cases, including when attached to `this` or `@` or `?.`; or when the first argument is an implicit object, e.g. `@set key: 'val'`.
+*   Statements such as `break` can now be used inside parentheses, e.g. `(doSomething(); break) while condition` or `(pick(key); break) for key of obj`.
+*   Bugfix for assigning to a property attached to `this`/`@` in destructuring, e.g. `({@prop = yes, @otherProp = no}) ->`.
+*   Bugfix for incorrect errors being thrown about calling `super` with a parameter attached to `this` when said parameter is in a lower scope, e.g. `class Child extends Parent then constructor: -> super(-> @prop)`.
+*   Bugfix to prevent a possible infinite loop when a `for` loop is given a variable to step by, e.g. `for x in [1..3] by step` (as opposed to `by 0.5` or some other primitive numeric value).
+*   Bugfix to no longer declare iterator variables twice when evaluating a range, e.g. `end = 3; fn [0..end]`.
+*   Bugfix for incorrect scope of variables in chained calls, e.g. `start(x = 3).then(-> x = 4)`.
+*   Bugfix for incorrect scope of variables in a function passed to `do`, e.g. `for [1..3] then masked = 10; do -> alert masked`.
+*   Bugfix to no longer throw a syntax error for a trailing comma in a function call, e.g. `fn arg1, arg2,`.
+*   Bugfix for an expression in a property access, e.g. `a[!b in c..]`.
+*   Bugfix to allow a line continuation backslash (`\`) at any point in a `for` line.
+
+```
+releaseHeader('2017-12-29', '2.1.1', '2.1.0')
+```
+
+*   Bugfix to set the correct context for executable class bodies. So in `class @B extends @A then @property = 1`, the `@` in `@property` now refers to the class, not the global object.
+*   Bugfix where anonymous classes were getting created using the same automatic variable name. They now each receive unique names, so as not to override each other.
+
+
+```
+releaseHeader('2017-12-10', '2.1.0', '2.0.3')
+```
+
+*   Computed property keys in object literals are now supported: `obj = { ['key' + i]: 42 }`, or `obj = [Symbol.iterator]: -> yield i++`.
+*   Skipping of array elements, a.k.a. elision, is now supported: `arr = [a, , b]`, or `[, protocol] = url.match /^(.*):\/\//`.
+*   [JSX fragments syntax](https://reactjs.org/blog/2017/11/28/react-v16.2.0-fragment-support.html) is now supported.
+*   Bugfix where `///` within a `#` line comment inside a `///` block regex was erroneously closing the regex, rather than being treated as part of the comment.
+*   Bugfix for incorrect output for object rest destructuring inside array destructuring.
+
+```
+releaseHeader('2017-11-26', '2.0.3', '2.0.2')
+```
+
+*   Bugfix for `export default` followed by an implicit object that contains an explicit object, for example `exportedMember: { obj... }`.
+*   Bugfix for `key, val of obj` after an implicit object member, e.g. `foo: bar for key, val of obj`.
+*   Bugfix for combining array and object destructuring, e.g. `[ ..., {a, b} ] = arr`.
+*   Bugfix for an edge case where it was possible to create a bound (`=>`) generator function, which should throw an error as such functions aren’t allowed in ES2015.
+*   Bugfix for source maps: `.map` files should always have the same base filename as the requested output filename. So `coffee --map --output foo.js test.coffee` should generate `foo.js` and `foo.js.map`.
+*   Bugfix for incorrect source maps generated when using `--transpile` with `--map` for multiple input files.
+*   Bugfix for comments at the beginning or end of input into the REPL (`coffee --interactive`).
+
 ```
 releaseHeader('2017-10-26', '2.0.2', '2.0.1')
 ```

documentation/sections/compatibility.md

@@ -1,5 +1,10 @@
 ### Compatibility
 
-With the exception of [modules](#modules) (`import` and `export` statements) and [JSX](#jsx), all the modern JavaScript features that CoffeeScript supports can run natively in Node 7.6+, meaning that Node can run CoffeeScript’s output without any further processing required. You can [run the tests in your browser](test.html) to see if your browser can do the same. For older browsers or older versions of Node, however, [transpilation](#transpilation) is required.
+Most modern JavaScript features that CoffeeScript supports can run natively in Node 7.6+, meaning that Node can run CoffeeScript’s output without any further processing required. Here are some notable exceptions:
 
-Support for modern JavaScript syntax is important to ensure compatibility with frameworks that assume modern features. Now that CoffeeScript compiles classes to the `class` keyword, it’s possible to `extend` a JavaScript class; that wasn’t possible in CoffeeScript 1. Parity in how language features work is also important on its own; CoffeeScript “is just JavaScript,” and so things like [function parameter default values](#breaking-changes-default-values) should behave the same in CoffeeScript as in JavaScript. Some such features behave slightly differently in JavaScript than they did in CoffeeScript 1; in such cases we are conforming with the JavaScript spec, and we’ve documented the differences as [breaking changes](#breaking-changes).
+*  [Modules](#modules) and [JSX](#jsx) always require transpilation.
+*  [Splats, a.k.a. object rest/spread syntax, for objects](http://coffeescript.org/#splats) are supported by Node 8.6+.
+*  The [regular expression `s` (dotall) flag](https://github.com/tc39/proposal-regexp-dotall-flag) is supported by Node 9+.
+*  [Async generator functions](https://github.com/tc39/proposal-async-iteration) are supported by Node 10+.
+
+This list may be incomplete, and excludes versions of Node that support newer features behind flags; please refer to [node.green](http://node.green/) for full details. You can [run the tests in your browser](test.html) to see what your browser supports. It is your responsibility to ensure that your runtime supports the modern features you use; or that you [transpile](#transpilation) your code. When in doubt, transpile.

documentation/sections/fat_arrow.md

@@ -1,6 +1,6 @@
 ## Bound (Fat Arrow) Functions
 
-In JavaScript, the `this` keyword is dynamically scoped to mean the object that the current function is attached to. If you pass a function as a callback or attach it to a different object, the original value of `this` will be lost. If you’re not familiar with this behavior, [this Digital Web article](http://64.13.255.16/articles/scope_in_javascript/) gives a good overview of the quirks.
+In JavaScript, the `this` keyword is dynamically scoped to mean the object that the current function is attached to. If you pass a function as a callback or attach it to a different object, the original value of `this` will be lost. If you’re not familiar with this behavior, [this Digital Web article](https://web.archive.org/web/20150316122013/http://www.digital-web.com/articles/scope_in_javascript) gives a good overview of the quirks.
 
 The fat arrow `=>` can be used to both define a function, and to bind it to the current value of `this`, right on the spot. This is helpful when using callback-based libraries like Prototype or jQuery, for creating iterator functions to pass to `each`, or event-handler functions to use with `on`. Functions created with the fat arrow are able to access properties of the `this` where they’re defined.
 

documentation/sections/modules.md

@@ -8,6 +8,6 @@ codeFor('modules')
 
 <div id="modules-note" class="bookmark"></div>
 
-Note that the CoffeeScript compiler **does not resolve modules**; writing an `import` or `export` statement in CoffeeScript will produce an `import` or `export` statement in the resulting output. It is your responsibility attach another transpiler, such as [Traceur Compiler](https://github.com/google/traceur-compiler), [Babel](http://babeljs.io/) or [Rollup](https://github.com/rollup/rollup), to convert this ES2015 syntax into code that will work in your target runtimes.
+Note that the CoffeeScript compiler **does not resolve modules**; writing an `import` or `export` statement in CoffeeScript will produce an `import` or `export` statement in the resulting output. It is your responsibility to [transpile](#transpilation) this ES2015 syntax into code that will work in your target runtimes.
 
 Also note that any file with an `import` or `export` statement will be output without a [top-level function safety wrapper](#lexical-scope); in other words, importing or exporting modules will automatically trigger [bare](#usage) mode for that file. This is because per the ES2015 spec, `import` or `export` statements must occur at the topmost scope.

documentation/sections/objects_and_arrays.md

@@ -6,12 +6,6 @@ The CoffeeScript literals for objects and arrays look very similar to their Java
 codeFor('objects_and_arrays', 'song.join(" … ")')
 ```
 
-In JavaScript, you can’t use reserved words, like `class`, as properties of an object, without quoting them as strings. CoffeeScript notices reserved words used as keys in objects and quotes them for you, so you don’t have to worry about it (say, when using jQuery).
-
-```
-codeFor('objects_reserved')
-```
-
 CoffeeScript has a shortcut for creating objects when you want the key to be set with a variable of the same name.
 
 ```

documentation/sections/operators.md

@@ -18,7 +18,7 @@ You can use `in` to test for array presence, and `of` to test for JavaScript obj
 
 In a `for` loop, `from` compiles to the [ES2015 `of`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...of). (Yes, it’s unfortunate; the CoffeeScript `of` predates the ES2015 `of`.)
 
-To simplify math expressions, `**` can be used for exponentiation and `//` performs integer division. `%` works just like in JavaScript, while `%%` provides [“dividend dependent modulo”](https://en.wikipedia.org/wiki/Modulo_operation):
+To simplify math expressions, `**` can be used for exponentiation and `//` performs floor division. `%` works just like in JavaScript, while `%%` provides [“dividend dependent modulo”](https://en.wikipedia.org/wiki/Modulo_operation):
 
 ```
 codeFor('modulo')
@@ -39,7 +39,7 @@ All together now:
 | `a in b` | `[].indexOf.call(b, a) >= 0` |
 | `a of b` | `a in b` |
 | `for a from b` | `for (a of b)` |
-| `a ** b` | `Math.pow(a, b)` |
+| `a ** b` | `a ** b` |
 | `a // b` | `Math.floor(a / b)` |
 | `a %% b` | `(a % b + b) % b` |
 

documentation/sections/scripts.md

@@ -2,6 +2,4 @@
 
 While it’s not recommended for serious use, CoffeeScripts may be included directly within the browser using `<script type="text/coffeescript">` tags. The source includes a compressed and minified version of the compiler ([Download current version here, 51k when gzipped](/v<%= majorVersion %>/browser-compiler/coffeescript.js)) as `docs/v<%= majorVersion %>/browser-compiler/coffeescript.js`. Include this file on a page with inline CoffeeScript tags, and it will compile and evaluate them in order.
 
-In fact, the little bit of glue script that runs [Try CoffeeScript](#try), as well as the code examples and other interactive parts of this site, is implemented in just this way. View source and look at the bottom of the page to see the example. Including the script also gives you access to `CoffeeScript.compile()` so you can pop open your JavaScript console and try compiling some strings.
-
 The usual caveats about CoffeeScript apply — your inline scripts will run within a closure wrapper, so if you want to expose global variables or functions, attach them to the `window` object.

documentation/sections/splats.md

@@ -22,4 +22,4 @@ codeFor('array_spread', 'all')
 codeFor('object_spread', 'JSON.stringify(currentUser)')
 ```
 
-In ECMAScript this is called [spread syntax](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator), and has been supported for arrays since ES2015 but is [coming soon for objects](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator#Spread_in_object_literals). Until object spread syntax is officially supported, the CoffeeScript compiler outputs the same polyfill as [Babel’s rest spread transform](https://babeljs.io/docs/plugins/transform-object-rest-spread/); but once it is supported, we will revise the compiler’s output. Note that there are [very subtle differences](https://developers.google.com/web/updates/2017/06/object-rest-spread) between the polyfill and the current proposal.
+In ECMAScript this is called [spread syntax](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator), and has been supported for arrays since ES2015 and objects since ES2018.

documentation/site/body.html

@@ -3,11 +3,11 @@
 <%= include('try.html') %>
 
 <div class="container-fluid" id="top">
-  <div class="row flex-nowrap">
-    <nav class="sidebar col-lg-3 bg-ribbed-light">
+  <div class="row flex-nowrap main-row">
+    <nav class="sidebar bg-ribbed-light">
       <%= include('sidebar.html') %>
     </nav>
-    <main class="main col-lg-9 ml-auto">
+    <main class="main">
       <header class="d-none d-lg-block">
         <p class="title-logo">
           <%= include('logo.svg') %>

documentation/site/code.css

@@ -1,7 +1,15 @@
-/* Adapted from https://github.com/FarhadG/code-mirror-themes/blob/master/themes/twilight.css */
+/* Adapted from https://github.com/FarhadG/code-mirror-themes/blob/master/themes/twilight.css and https://github.com/codemirror/CodeMirror/blob/master/theme/twilight.css */
+
+/* CodeMirror general styling */
 
 .CodeMirror,
 .placeholder-code {
+  /* https://codemirror.net/demo/resize.html */
+  height: auto;
+  background: transparent;
+  font-family: 'Roboto Mono';
+  font-weight: 400;
+  line-height: 1.25;
   letter-spacing: 0.3px;
   color: #f8f8f8;
   /* Prevent mobile Safari from zooming in on our code editors; the code is 16px naturally, but somehow being explicit about it prevents the zooming */
@@ -10,7 +18,7 @@
 @media (min-width: 768px) {
   .CodeMirror,
   .placeholder-code {
-    font-size: 90%; /* Matching Bootstrap’s font size for code, which calculates to 14.4px */
+    font-size: 87.5%; /* Matching Bootstrap’s font size for code, which calculates to 14.4px */
   }
 }
 .CodeMirror-lines {
@@ -21,6 +29,13 @@
   margin-bottom: 1.37em;
   white-space: pre-wrap;
 }
+.CodeMirror pre,
+pre.placeholder-code {
+  line-height: 1.4em;
+}
+.CodeMirror-code:focus {
+  outline: none;
+}
 div.CodeMirror-cursor {
   border-left: 3px solid #f8f8f8;
 }
@@ -30,27 +45,18 @@ div.CodeMirror-cursor {
 .CodeMirror-selected {
   background: #ddf0ff33;
 }
-.cm-comment,
-.placeholder-code .comment {
-  font-style: italic;
-  color: #5f5a60;
-}
+
+/* Syntax highlighting */
+
 .cm-keyword,
 .placeholder-code .keyword {
   color: #cda869;
 }
-.cm-string,
-.placeholder-code .string {
-  color: #8f9d6a;
-}
-.cm-property,
-.placeholder-code .attribute {
-  color: #dad085;
-}
 .cm-atom {
   color: #dad085;
 }
 .cm-number,
+.cm-meta,
 .placeholder-code .number,
 .placeholder-code .built_in,
 .placeholder-code .builtin-name,
@@ -61,6 +67,18 @@ div.CodeMirror-cursor {
 .placeholder-code .link {
   color: #dad085;
 }
+.cm-def {
+  color: #f8f8f8;
+}
+span.cm-variable-2,
+span.cm-tag {
+  color: #f8f8f8;
+}
+span.cm-variable-3,
+span.cm-def,
+span.cm-type {
+  color: #f8f8f8;
+}
 .cm-operator,
 .placeholder-code .punctuation,
 .placeholder-code .symbol,
@@ -69,9 +87,50 @@ div.CodeMirror-cursor {
 .placeholder-code .operator {
   color: #cda869;
 }
+.cm-comment,
+.placeholder-code .comment {
+  font-style: italic;
+  color: #5f5a60;
+}
+.cm-string,
+.cm-string-2,
+.placeholder-code .string {
+  color: #8f9d6a;
+}
+.cm-property,
+.placeholder-code .attribute {
+  color: #dad085;
+}
+.cm-builtin {
+  color: #cda869;
+}
+.cm-tag {
+  color: #997643;
+}
+.cm-attribute {
+  color: #d6bb6d;
+}
+.cm-header {
+  color: #FF6400;
+}
+.cm-hr {
+  color: #AEAEAE;
+}
+.cm-link {
+  color: #ad9361;
+  font-style: italic;
+  text-decoration: none;
+}
+.cm-error {
+  border-bottom: 1px solid rgba(142, 22, 22, 0.67);
+}
 
 /* Uneditable code blocks are inverted, so use darker versions of the above */
 
+.uneditable-code-block code {
+  padding: 0;
+}
+
 .uneditable-code-block .comment {
   font-style: italic;
   color: #837B85;

documentation/site/docs.coffee

@@ -1,6 +1,18 @@
 unless window.location.origin # Polyfill `location.origin` for IE < 11
   window.location.origin = "#{window.location.protocol}//#{window.location.hostname}"
 
+
+# Initialize Google Analytics
+window.GA_TRACKING_ID = 'UA-106156830-1'
+window.dataLayer ?= []
+window.gtag = ->
+  window.dataLayer.push arguments
+  return
+window.gtag 'js', new Date()
+window.gtag 'config', window.GA_TRACKING_ID
+
+
+# Initialize the CoffeeScript docs interactions
 $(document).ready ->
   # Mobile navigation
   toggleSidebar = ->
@@ -21,14 +33,14 @@ $(document).ready ->
 
   # Initialize Scrollspy for sidebar navigation; https://getbootstrap.com/docs/4.0/components/scrollspy/
   # See also http://www.codingeverything.com/2014/02/BootstrapDocsSideBar.html and http://jsfiddle.net/KyleMit/v6zhz/
-  $('body').scrollspy
+  $('.main').scrollspy
     target: '#contents'
     offset: Math.round $('main').css('padding-top').replace('px', '')
 
   initializeScrollspyFromHash = (hash) ->
     $("#contents a.active[href!='#{hash}']").removeClass 'show'
 
-  $(window).on 'activate.bs.scrollspy', (event, target) -> # Why `window`? https://github.com/twbs/bootstrap/issues/20086
+  $('.main').on 'activate.bs.scrollspy', (event, target) ->
     # We only want one active link in the nav
     $("#contents a.active[href!='#{target.relatedTarget}']").removeClass 'show'
     $target = $("#contents a[href='#{target.relatedTarget}']")
@@ -165,6 +177,11 @@ $(document).ready ->
     toggleTry yes
   $('[data-close="try"]').click closeTry
 
+  $('[data-action="scroll-to-top"]').click (event) ->
+    return if $('#try').hasClass('show')
+    $('.main')[0].scrollTop = 0
+    setTimeout clearHash, 10
+
   clearHash = ->
     window.history.replaceState {}, document.title, window.location.pathname
 

documentation/site/docs.css

@@ -79,14 +79,18 @@ button:focus, .navbar-dark .navbar-toggler:focus {
 }
 
 
+/*
+ * Layout; based on https://codepen.io/Sphinxxxx/pen/WjwbEO
+ */
+.main-row {
+  height: calc(100vh - 3.5rem);
+}
+
 /*
  * Sidebar
  */
 
 .sidebar {
-  position: fixed;
-  top: 3.5em;
-  height: calc(100% - 3.5rem);
   /* Scrollable contents if viewport is shorter than content */
   overflow-y: auto;
   overflow-x: hidden;
@@ -102,6 +106,9 @@ button:focus, .navbar-dark .navbar-toggler:focus {
 }
 @media screen and (max-width: 991px) {
   .sidebar {
+    position: fixed;
+    top: 3.5em;
+    height: calc(100% - 3.5rem);
     left: -100%;
     transition: 0.25s left ease-in-out;
   }
@@ -109,6 +116,11 @@ button:focus, .navbar-dark .navbar-toggler:focus {
     left: 0;
   }
 }
+@media (min-width: 992px) {
+  .sidebar {
+    flex: 0 0 auto;
+  }
+}
 
 .contents {
   padding: 0.5em 0 0.5em 0.5em;
@@ -139,10 +151,13 @@ button:focus, .navbar-dark .navbar-toggler:focus {
  */
 
 .main {
+  max-width: 100%;
   padding: 1.3em;
 }
 @media (min-width: 992px) {
   .main {
+    flex: 1 1 auto;
+    overflow: auto;
     padding-right: 2em;
     padding-left: 2em;
   }
@@ -221,12 +236,6 @@ h3, h4, h2 time {
   font-weight: 400;
 }
 
-.main section {
-  /* Offset the anchor so that clicking on the sidebar links don’t hide the heading under the header bar */
-  padding-top: 2.3rem;
-  margin-top: -2.3rem;
-}
-
 @media (min-width: 1200px) {
   .main > header, .main section > h2, .main section > h3, .main section > h4, .main section > p, .main section > blockquote, .main section > ul, .main section > table {
     max-width: 80%;
@@ -246,7 +255,7 @@ code {
 
 
 /*
- * Code examples
+ * Chrome around code examples; see code.css for the styling of the code blocks themselves
  */
 
 textarea {
@@ -281,31 +290,7 @@ textarea {
 
 .play-button {
   height: 1em;
-}
-
-.CodeMirror pre, pre.placeholder-code {
-  line-height: 1.4em;
-}
-
-.CodeMirror,
-.placeholder-code {
-  /* https://codemirror.net/demo/resize.html */
-  height: auto;
-  background: transparent;
-  font-family: 'Roboto Mono';
-  font-weight: 400;
-  line-height: 1.25;
-  font-size: 0.9em;
-}
-@media (min-width: 768px) {
-  .CodeMirror,
-  .placeholder-code {
-    font-size: 1em;
-  }
-}
-
-.CodeMirror-code:focus {
-  outline: none;
+  width: 1em;
 }
 
 .javascript-output-column .CodeMirror-cursor {
@@ -324,6 +309,8 @@ textarea {
   right: 0;
   opacity: 0;
   transition: opacity 0.15s ease-in-out;
+  z-index: -1001;
+  background-color: #2f2625;
 }
 .try-coffeescript.show {
   opacity: 1;

documentation/site/icon.svg

@@ -2,5 +2,5 @@
     <title>
         CoffeeScript Logo
     </title>
-    <path d="M106 228.6c.5 2.3-.9 4.4-5 6.5-5.5-3.1-16.9-4.4-26.7-3.5-10.4.9-19.4 4.2-17.9 11.3 1.5 7.1 11.7 11 29.5 9.5 43.6-3.8 43.4-33.3 107.4-39 49.8-4.4 77.8 11 81.8 29.7 3.1 14.7-9.1 28.6-45.2 31.8-32 2.8-50.7-5.6-52.6-14.6-1-4.5 1.8-11.3 17.2-13.1 1.5 7 10.6 14.4 31.1 12.6 14.8-1.3 27.6-6.6 25.9-14.9-1.8-8.6-17.7-13.7-42.6-11.5-50.7 4.5-63.2 32.5-106.8 36.3-30.8 2.7-55.9-8.5-59.4-25.1-1.3-6.1-1.4-21 31.2-23.9 17.1-1.5 30.7 1.5 32.1 7.9zM-56.4 402.5c-14.3 18-20.4 38.8-19.2 59.2 1.2 20.4 11.4 37.1 26.9 50.2C-32 525-14 528.6 6.4 525c7.8-1.2 16.7-5.3 24.5-7.8-16.7 0-31-5.3-44.9-16.7-15.5-11.4-25.7-26.9-28.2-46.1-3.7-18 0-34.7 10.2-49 11.4-14.3 25.7-22 44.9-24.5 19.2-1.2 35.9 3.7 52.6 15.5-3.7-5.3-9-9-14.3-14.3-16.7-11.4-34.7-16.7-56.7-11.4-19.9 3.6-36.7 13.8-50.9 31.8zm223.6-96.3c-53.9 0-101.6-5.3-136.3-13.1-37.1-9-56.7-19.2-56.7-32.2 0-5.3 2.4-10.2 10.2-15.5-23.3 9-35.9 16.7-35.9 28.2 1.2 13.1 22 25.7 64.5 35.9 40 10.2 91.4 15.5 153 15.5 62.8 0 113-5.3 153-15.5 42.4-10.2 62.8-23.3 62.8-35.9 0-9-9-18-25.7-24.5 3.7 2.4 6.5 6.5 6.5 11.4 0 13.1-19.2 23.3-57.9 32.2-36 8.2-82.1 13.5-137.5 13.5zm153 35.9c-40 9-91.4 15.5-153 15.5-62.8 0-114.2-6.5-154.2-15.5-35.9-9-55.1-19.2-61.6-29.4 6.5 44.9 22 87.3 42.4 124.8 15.5 23.3 31 43.7 46.1 65.7 6.5 13.1 11.4 25.7 14.3 38.8 10.2 14.3 24.5 23.3 42.4 28.2 22 7.8 44.9 11.4 68.1 10.2h2.4c23.3 1.2 47.7-2.4 70.6-10.2 16.7-5.3 31-14.3 41.2-28.2h1.2c2.4-13.1 6.5-25.7 13.1-38.8 15.5-22 31-42.4 46.1-65.7 20.4-37.1 34.7-79.6 42.4-124.8-7.7 11.4-26.9 21.6-61.5 29.4z"/>
+    <path d="M106 228.6c.5 2.3-.9 4.4-5 6.5-5.5-3.1-16.9-4.4-26.7-3.5-10.4.9-19.4 4.2-17.9 11.3 1.5 7.1 11.7 11 29.5 9.5 43.6-3.8 43.4-33.3 107.4-39 49.8-4.4 77.8 11 81.8 29.7 3.1 14.7-9.1 28.6-45.2 31.8-32 2.8-50.7-5.6-52.6-14.6-1-4.5 1.8-11.3 17.2-13.1 1.5 7 10.6 14.4 31.1 12.6 14.8-1.3 27.6-6.6 25.9-14.9-1.8-8.6-17.7-13.7-42.6-11.5-50.7 4.5-63.2 32.5-106.8 36.3-30.8 2.7-55.9-8.5-59.4-25.1-1.3-6.1-1.4-21 31.2-23.9 17.1-1.5 30.7 1.5 32.1 7.9zM-56.4 402.5c-14.3 18-20.4 38.8-19.2 59.2 1.2 20.4 11.4 37.1 26.9 50.2C-32 525-14 528.6 6.4 525c7.8-1.2 16.7-5.3 24.5-7.8-16.7 0-31-5.3-44.9-16.7-15.5-11.4-25.7-26.9-28.2-46.1-3.7-18 0-34.7 10.2-49 11.4-14.3 25.7-22 44.9-24.5 19.2-1.2 35.9 3.7 52.6 15.5-3.7-5.3-9-9-14.3-14.3-16.7-11.4-34.7-16.7-56.7-11.4-19.9 3.6-36.7 13.8-50.9 31.8zm223.6-96.3c-53.9 0-101.6-5.3-136.3-13.1-37.1-9-56.7-19.2-56.7-32.2 0-5.3 2.4-10.2 10.2-15.5-23.3 9-35.9 16.7-35.9 28.2 1.2 13.1 22 25.7 64.5 35.9 40 10.2 91.4 15.5 153 15.5 62.8 0 113-5.3 153-15.5 42.4-10.2 62.8-23.3 62.8-35.9 0-9-9-18-25.7-24.5 3.7 2.4 6.5 6.5 6.5 11.4 0 13.1-19.2 23.3-57.9 32.2-36 8.2-82.1 13.5-137.5 13.5zm153 35.9c-40 9-91.4 15.5-153 15.5-62.8 0-114.2-6.5-154.2-15.5-35.9-9-55.1-19.2-61.6-29.4 6.5 44.9 22 87.3 42.4 124.8 15.5 23.3 31 43.7 46.1 65.7 6.5 13.1 11.4 25.7 14.3 38.8 10.2 14.3 24.5 23.3 42.4 28.2 22 7.8 44.9 11.4 68.1 10.2h2.4c23.3 1.2 47.7-2.4 70.6-10.2 16.7-5.3 31-14.3 41.2-28.2h1.2c2.4-13.1 6.5-25.7 13.1-38.8 15.5-22 31-42.4 46.1-65.7 20.4-37.1 34.7-79.6 42.4-124.8-7.7 11.4-26.9 21.6-61.5 29.4z"></path>
 </svg>

documentation/site/logo.svg

@@ -2,5 +2,5 @@
   <title>
     CoffeeScript Logo
   </title>
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documentation/site/navbar.html

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-  <a class="navbar-brand" href="#" data-close="try"><%= include('logo.svg') %></a>
+  <a class="navbar-brand" href="#" data-close="try" data-action="scroll-to-top"><%= include('logo.svg') %></a>
   <button class="navbar-toggler" type="button" data-toggle="offcanvas" data-close="try" aria-label="Toggle sidebar">
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documentation/site/play.svg

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 <svg class="play-button" viewBox="0 0 24 24">
-  <path d="M2.56-0.01v24.02L21.44 11.98 2.56-0.01z"/>
+	<path d="M2.56-0.01v24.02L21.44 11.98 2.56-0.01z"></path>
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documentation/site/scripts.html

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-<script>
-  window.Popper = {}; // Remove if we want to use Bootstrap tooltips
-</script>
-<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/js/bootstrap.min.js" integrity="sha384-h0AbiXch4ZDo7tp9hKZ4TsHbi047NrKGLO3SEJAg45jXxnGIfYzk4Si90RDIqNm1" crossorigin="anonymous"></script>
-<script src="https://cdn.jsdelivr.net/combine/npm/codemirror@5.29.0/lib/codemirror.js,npm/codemirror@5.29.0/mode/coffeescript/coffeescript.js,npm/codemirror@5.29.0/addon/lint/coffeescript-lint.js,npm/codemirror@5.29.0/mode/javascript/javascript.js"></script>
+<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js" integrity="sha384-uefMccjFJAIv6A+rW+L4AHf99KvxDjWSu1z9VI8SKNVmz4sk7buKt/6v9KI65qnm" crossorigin="anonymous"></script>
+<script src="https://cdn.jsdelivr.net/combine/npm/codemirror@5.37.0/lib/codemirror.js,npm/codemirror@5.37.0/mode/coffeescript/coffeescript.js,npm/codemirror@5.37.0/addon/lint/coffeescript-lint.js,npm/codemirror@5.37.0/mode/javascript/javascript.js"></script>
 
 <script src="browser-compiler/coffeescript.js"></script>
 <script>
 <%= includeScript('docs.coffee') %>
 </script>
 <script async src="https://www.googletagmanager.com/gtag/js?id=UA-106156830-1"></script>
-<script>
-  window.GA_TRACKING_ID = 'UA-106156830-1';
-  window.dataLayer = window.dataLayer || [];
-  function gtag(){dataLayer.push(arguments)};
-  gtag('js', new Date());
-  gtag('config', GA_TRACKING_ID);
-</script>

documentation/site/styles.html

@@ -1,8 +1,8 @@
-<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-/Y6pD6FV/Vv2HJnA6t+vslU6fwYXjCFtcEpHbNJ0lyAFsXTsjBbfaDjzALeQsN6M" crossorigin="anonymous">
+<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous">
 <!-- The CoffeeScript logo font is Google’s Galada -->
 <link href="https://fonts.googleapis.com/css?family=Alegreya+Sans:400,800|Lato:300,300i,400,700|Roboto+Mono:400,400i" rel="stylesheet" crossorigin="anonymous">
-<link rel="stylesheet" href="https://cdn.jsdelivr.net/codemirror/4.5.0/codemirror.css" crossorigin="anonymous">
+<link href="https://cdn.jsdelivr.net/npm/codemirror@5.37.0/lib/codemirror.css" rel="stylesheet" crossorigin="anonymous">
 <style>
-<%= include('docs.css') %>
 <%= include('code.css') %>
+<%= include('docs.css') %>
 </style>

lib/coffeescript/browser.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.0.2
+// Generated by CoffeeScript 2.3.0
 (function() {
   // This **Browser** compatibility layer extends core CoffeeScript functions
   // to make things work smoothly when compiling code directly in the browser.
@@ -77,7 +77,7 @@
   // all script tags with a content-type of `text/coffeescript`.
   // This happens on page load.
   runScripts = function() {
-    var coffees, coffeetypes, execute, fn, i, index, j, len, s, script, scripts;
+    var coffees, coffeetypes, execute, i, index, j, len, s, script, scripts;
     scripts = window.document.getElementsByTagName('script');
     coffeetypes = ['text/coffeescript', 'text/literate-coffeescript'];
     coffees = (function() {
@@ -101,32 +101,31 @@
         return execute();
       }
     };
-    fn = function(script, i) {
-      var options, source;
-      options = {
-        literate: script.type === coffeetypes[1]
-      };
-      source = script.src || script.getAttribute('data-src');
-      if (source) {
-        options.filename = source;
-        return CoffeeScript.load(source, function(param) {
-          coffees[i] = param;
-          return execute();
-        }, options, true);
-      } else {
-        // `options.filename` defines the filename the source map appears as
-        // in Developer Tools. If a script tag has an `id`, use that as the
-        // filename; otherwise use `coffeescript`, or `coffeescript1` etc.,
-        // leaving the first one unnumbered for the common case that there’s
-        // only one CoffeeScript script block to parse.
-        options.filename = script.id && script.id !== '' ? script.id : `coffeescript${(i !== 0 ? i : '')}`;
-        options.sourceFiles = ['embedded'];
-        return coffees[i] = [script.innerHTML, options];
-      }
-    };
     for (i = j = 0, len = coffees.length; j < len; i = ++j) {
       script = coffees[i];
-      fn(script, i);
+      (function(script, i) {
+        var options, source;
+        options = {
+          literate: script.type === coffeetypes[1]
+        };
+        source = script.src || script.getAttribute('data-src');
+        if (source) {
+          options.filename = source;
+          return CoffeeScript.load(source, function(param) {
+            coffees[i] = param;
+            return execute();
+          }, options, true);
+        } else {
+          // `options.filename` defines the filename the source map appears as
+          // in Developer Tools. If a script tag has an `id`, use that as the
+          // filename; otherwise use `coffeescript`, or `coffeescript1` etc.,
+          // leaving the first one unnumbered for the common case that there’s
+          // only one CoffeeScript script block to parse.
+          options.filename = script.id && script.id !== '' ? script.id : `coffeescript${(i !== 0 ? i : '')}`;
+          options.sourceFiles = ['embedded'];
+          return coffees[i] = [script.innerHTML, options];
+        }
+      })(script, i);
     }
     return execute();
   };

lib/coffeescript/cake.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.0.2
+// Generated by CoffeeScript 2.3.0
 (function() {
   // `cake` is a simplified version of [Make](http://www.gnu.org/software/make/)
   // ([Rake](http://rake.rubyforge.org/), [Jake](https://github.com/280north/jake))

lib/coffeescript/coffeescript.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.0.2
+// Generated by CoffeeScript 2.3.0
 (function() {
   // CoffeeScript can be used both on the server, as a command-line compiler based
   // on Node.js/V8, or to run CoffeeScript directly in the browser. This module
@@ -85,7 +85,7 @@
   // object, where sourceMap is a sourcemap.coffee#SourceMap object, handy for
   // doing programmatic lookups.
   exports.compile = compile = withPrettyErrors(function(code, options = {}) {
-    var currentColumn, currentLine, encoded, filename, fragment, fragments, generateSourceMap, header, i, j, js, len, len1, map, newLines, ref, ref1, sourceMapDataURI, sourceURL, token, tokens, transpiler, transpilerOutput, v3SourceMap;
+    var currentColumn, currentLine, encoded, filename, fragment, fragments, generateSourceMap, header, i, j, js, len, len1, map, newLines, ref, ref1, sourceMapDataURI, sourceURL, token, tokens, transpiler, transpilerOptions, transpilerOutput, v3SourceMap;
     // Clone `options`, to avoid mutating the `options` object passed in.
     options = Object.assign({}, options);
     // Always generate a source map if no filename is passed in, since without a
@@ -177,13 +177,14 @@
       // is run via the CLI or Node API.
       transpiler = options.transpile.transpile;
       delete options.transpile.transpile;
+      transpilerOptions = Object.assign({}, options.transpile);
       // See https://github.com/babel/babel/issues/827#issuecomment-77573107:
       // Babel can take a v3 source map object as input in `inputSourceMap`
       // and it will return an *updated* v3 source map object in its output.
-      if (v3SourceMap && (options.transpile.inputSourceMap == null)) {
-        options.transpile.inputSourceMap = v3SourceMap;
+      if (v3SourceMap && (transpilerOptions.inputSourceMap == null)) {
+        transpilerOptions.inputSourceMap = v3SourceMap;
       }
-      transpilerOutput = transpiler(js, options.transpile);
+      transpilerOutput = transpiler(js, transpilerOptions);
       js = transpilerOutput.code;
       if (v3SourceMap && transpilerOutput.map) {
         v3SourceMap = transpilerOutput.map;

lib/coffeescript/command.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.0.2
+// Generated by CoffeeScript 2.3.0
 (function() {
   // The `coffee` utility. Handles command-line compilation of CoffeeScript
   // into various forms: saved into `.js` files or printed to stdout
@@ -534,7 +534,7 @@
   // same directory as the `.js` file.
   writeJs = function(base, sourcePath, js, jsPath, generatedSourceMap = null) {
     var compile, jsDir, sourceMapPath;
-    sourceMapPath = outputPath(sourcePath, base, ".js.map");
+    sourceMapPath = `${jsPath}.map`;
     jsDir = path.dirname(jsPath);
     compile = function() {
       if (opts.compile) {

lib/coffeescript/grammar.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.0.2
+// Generated by CoffeeScript 2.3.0
 (function() {
   // The CoffeeScript parser is generated by [Jison](https://github.com/zaach/jison)
   // from this grammar file. Jison is a bottom-up parser generator, similar in
@@ -97,7 +97,7 @@
     // Block and statements, which make up a line in a body. YieldReturn is a
     // statement, but not included in Statement because that results in an ambiguous
     // grammar.
-    Line: [o('Expression'), o('Statement'), o('FuncDirective')],
+    Line: [o('Expression'), o('ExpressionLine'), o('Statement'), o('FuncDirective')],
     FuncDirective: [o('YieldReturn'), o('AwaitReturn')],
     // Pure statements which cannot be expressions.
     Statement: [
@@ -114,6 +114,10 @@
     // is one. Blocks serve as the building blocks of many other rules, making
     // them somewhat circular.
     Expression: [o('Value'), o('Code'), o('Operation'), o('Assign'), o('If'), o('Try'), o('While'), o('For'), o('Switch'), o('Class'), o('Throw'), o('Yield')],
+    // Expressions which are written in single line and would otherwise require being
+    // wrapped in braces: E.g `a = b if do -> f a is 1`, `if f (a) -> a*2 then ...`,
+    // `for x in do (obj) -> f obj when x > 8 then f x`
+    ExpressionLine: [o('CodeLine'), o('IfLine'), o('OperationLine')],
     Yield: [
       o('YIELD',
       function() {
@@ -283,7 +287,14 @@
       })
     ],
     SimpleObjAssignable: [o('Identifier'), o('Property'), o('ThisProperty')],
-    ObjAssignable: [o('SimpleObjAssignable'), o('AlphaNumeric')],
+    ObjAssignable: [
+      o('SimpleObjAssignable'),
+      o('[ Expression ]',
+      function() {
+        return new Value(new ComputedPropertyName($2));
+      }),
+      o('AlphaNumeric')
+    ],
     // Object literal spread properties.
     ObjRestValue: [
       o('SimpleObjAssignable ...',
@@ -399,6 +410,22 @@
       $1);
       })
     ],
+    // The Codeline is the **Code** node with **Line** instead of indented **Block**.
+    CodeLine: [
+      o('PARAM_START ParamList PARAM_END FuncGlyph Line',
+      function() {
+        return new Code($2,
+      LOC(5)(Block.wrap([$5])),
+      $4,
+      LOC(1)(new Literal($1)));
+      }),
+      o('FuncGlyph Line',
+      function() {
+        return new Code([],
+      LOC(2)(Block.wrap([$2])),
+      $1);
+      })
+    ],
     // CoffeeScript has two different symbols for functions. `->` is for ordinary
     // functions, and `=>` is for functions bound to the current value of *this*.
     FuncGlyph: [
@@ -822,6 +849,10 @@
       function() {
         return new ExportDefaultDeclaration($3);
       }),
+      o('EXPORT DEFAULT INDENT Object OUTDENT',
+      function() {
+        return new ExportDefaultDeclaration(new Value($4));
+      }),
       o('EXPORT EXPORT_ALL FROM String',
       function() {
         return new ExportAllDeclaration(new Literal($2),
@@ -950,9 +981,14 @@
       function() {
         return new Arr([]);
       }),
-      o('[ ArgList OptComma ]',
+      o('[ Elisions ]',
       function() {
         return new Arr($2);
+      }),
+      o('[ ArgElisionList OptElisions ]',
+      function() {
+        return new Arr([].concat($2,
+      $3));
       })
     ],
     // Inclusive and exclusive range dots.
@@ -973,6 +1009,12 @@
         return new Range($2,
       $4,
       $3);
+      }),
+      o('[ ExpressionLine RangeDots Expression ]',
+      function() {
+        return new Range($2,
+      $4,
+      $3);
       })
     ],
     // Array slice literals.
@@ -989,6 +1031,18 @@
       null,
       $2);
       }),
+      o('ExpressionLine RangeDots Expression',
+      function() {
+        return new Range($1,
+      $3,
+      $2);
+      }),
+      o('ExpressionLine RangeDots',
+      function() {
+        return new Range($1,
+      null,
+      $2);
+      }),
       o('RangeDots Expression',
       function() {
         return new Range(null,
@@ -1002,8 +1056,7 @@
       $1);
       })
     ],
-    // The **ArgList** is both the list of objects passed into a function call,
-    // as well as the contents of an array literal
+    // The **ArgList** is the list of objects passed into a function call
     // (i.e. comma-separated expressions). Newlines work as well.
     ArgList: [
       o('Arg',
@@ -1030,21 +1083,88 @@
     // Valid arguments are Blocks or Splats.
     Arg: [
       o('Expression'),
+      o('ExpressionLine'),
       o('Splat'),
       o('...',
       function() {
         return new Expansion;
       })
     ],
+    // The **ArgElisionList** is the list of objects, contents of an array literal
+    // (i.e. comma-separated expressions and elisions). Newlines work as well.
+    ArgElisionList: [
+      o('ArgElision'),
+      o('ArgElisionList , ArgElision',
+      function() {
+        return $1.concat($3);
+      }),
+      o('ArgElisionList OptElisions TERMINATOR ArgElision',
+      function() {
+        return $1.concat($2,
+      $4);
+      }),
+      o('INDENT ArgElisionList OptElisions OUTDENT',
+      function() {
+        return $2.concat($3);
+      }),
+      o('ArgElisionList OptElisions INDENT ArgElisionList OptElisions OUTDENT',
+      function() {
+        return $1.concat($2,
+      $4,
+      $5);
+      })
+    ],
+    ArgElision: [
+      o('Arg',
+      function() {
+        return [$1];
+      }),
+      o('Elisions Arg',
+      function() {
+        return $1.concat($2);
+      })
+    ],
+    OptElisions: [
+      o('OptComma',
+      function() {
+        return [];
+      }),
+      o(', Elisions',
+      function() {
+        return [].concat($2);
+      })
+    ],
+    Elisions: [
+      o('Elision',
+      function() {
+        return [$1];
+      }),
+      o('Elisions Elision',
+      function() {
+        return $1.concat($2);
+      })
+    ],
+    Elision: [
+      o(',',
+      function() {
+        return new Elision;
+      })
+    ],
     // Just simple, comma-separated, required arguments (no fancy syntax). We need
     // this to be separate from the **ArgList** for use in **Switch** blocks, where
     // having the newlines wouldn't make sense.
     SimpleArgs: [
       o('Expression'),
+      o('ExpressionLine'),
       o('SimpleArgs , Expression',
       function() {
         return [].concat($1,
       $3);
+      }),
+      o('SimpleArgs , ExpressionLine',
+      function() {
+        return [].concat($1,
+      $3);
       })
     ],
     // The variants of *try/catch/finally* exception handling blocks.
@@ -1118,6 +1238,34 @@
       })
     ],
     // The condition portion of a while loop.
+    WhileLineSource: [
+      o('WHILE ExpressionLine',
+      function() {
+        return new While($2);
+      }),
+      o('WHILE ExpressionLine WHEN ExpressionLine',
+      function() {
+        return new While($2,
+      {
+          guard: $4
+        });
+      }),
+      o('UNTIL ExpressionLine',
+      function() {
+        return new While($2,
+      {
+          invert: true
+        });
+      }),
+      o('UNTIL ExpressionLine WHEN ExpressionLine',
+      function() {
+        return new While($2,
+      {
+          invert: true,
+          guard: $4
+        });
+      })
+    ],
     WhileSource: [
       o('WHILE Expression',
       function() {
@@ -1130,6 +1278,13 @@
           guard: $4
         });
       }),
+      o('WHILE ExpressionLine WHEN Expression',
+      function() {
+        return new While($2,
+      {
+          guard: $4
+        });
+      }),
       o('UNTIL Expression',
       function() {
         return new While($2,
@@ -1138,6 +1293,14 @@
         });
       }),
       o('UNTIL Expression WHEN Expression',
+      function() {
+        return new While($2,
+      {
+          invert: true,
+          guard: $4
+        });
+      }),
+      o('UNTIL ExpressionLine WHEN Expression',
       function() {
         return new While($2,
       {
@@ -1153,6 +1316,10 @@
       function() {
         return $1.addBody($2);
       }),
+      o('WhileLineSource Block',
+      function() {
+        return $1.addBody($2);
+      }),
       o('Statement  WhileSource',
       function() {
         return $2.addBody(LOC(1)(Block.wrap([$1])));
@@ -1180,55 +1347,94 @@
     // Comprehensions can either be normal, with a block of expressions to execute,
     // or postfix, with a single expression.
     For: [
-      o('Statement  ForBody',
+      o('Statement    ForBody',
       function() {
-        return new For($1,
-      $2);
+        return $2.addBody($1);
       }),
-      o('Expression ForBody',
+      o('Expression   ForBody',
       function() {
-        return new For($1,
-      $2);
+        return $2.addBody($1);
       }),
-      o('ForBody    Block',
+      o('ForBody      Block',
       function() {
-        return new For($2,
-      $1);
+        return $1.addBody($2);
+      }),
+      o('ForLineBody  Block',
+      function() {
+        return $1.addBody($2);
       })
     ],
     ForBody: [
       o('FOR Range',
       function() {
-        return {
+        return new For([],
+      {
           source: LOC(2)(new Value($2))
-        };
+        });
       }),
       o('FOR Range BY Expression',
       function() {
-        return {
+        return new For([],
+      {
           source: LOC(2)(new Value($2)),
           step: $4
-        };
+        });
       }),
       o('ForStart ForSource',
       function() {
-        $2.own = $1.own;
-        $2.ownTag = $1.ownTag;
-        $2.name = $1[0];
-        $2.index = $1[1];
-        return $2;
+        return $1.addSource($2);
+      })
+    ],
+    ForLineBody: [
+      o('FOR Range BY ExpressionLine',
+      function() {
+        return new For([],
+      {
+          source: LOC(2)(new Value($2)),
+          step: $4
+        });
+      }),
+      o('ForStart ForLineSource',
+      function() {
+        return $1.addSource($2);
       })
     ],
     ForStart: [
       o('FOR ForVariables',
       function() {
-        return $2;
+        return new For([],
+      {
+          name: $2[0],
+          index: $2[1]
+        });
+      }),
+      o('FOR AWAIT ForVariables',
+      function() {
+        var index,
+      name;
+        [name,
+      index] = $3;
+        return new For([],
+      {
+          name,
+          index,
+          await: true,
+          awaitTag: LOC(2)(new Literal($2))
+        });
       }),
       o('FOR OWN ForVariables',
       function() {
-        $3.own = true;
-        $3.ownTag = LOC(2)(new Literal($2));
-        return $3;
+        var index,
+      name;
+        [name,
+      index] = $3;
+        return new For([],
+      {
+          name,
+          index,
+          own: true,
+          ownTag: LOC(2)(new Literal($2))
+        });
       })
     ],
     // An array of all accepted values for a variable inside the loop.
@@ -1283,6 +1489,13 @@
           guard: $4
         };
       }),
+      o('FORIN ExpressionLine WHEN Expression',
+      function() {
+        return {
+          source: $2,
+          guard: $4
+        };
+      }),
       o('FOROF Expression WHEN Expression',
       function() {
         return {
@@ -1291,6 +1504,14 @@
           object: true
         };
       }),
+      o('FOROF ExpressionLine WHEN Expression',
+      function() {
+        return {
+          source: $2,
+          guard: $4,
+          object: true
+        };
+      }),
       o('FORIN Expression BY Expression',
       function() {
         return {
@@ -1298,6 +1519,13 @@
           step: $4
         };
       }),
+      o('FORIN ExpressionLine BY Expression',
+      function() {
+        return {
+          source: $2,
+          step: $4
+        };
+      }),
       o('FORIN Expression WHEN Expression BY Expression',
       function() {
         return {
@@ -1306,6 +1534,30 @@
           step: $6
         };
       }),
+      o('FORIN ExpressionLine WHEN Expression BY Expression',
+      function() {
+        return {
+          source: $2,
+          guard: $4,
+          step: $6
+        };
+      }),
+      o('FORIN Expression WHEN ExpressionLine BY Expression',
+      function() {
+        return {
+          source: $2,
+          guard: $4,
+          step: $6
+        };
+      }),
+      o('FORIN ExpressionLine WHEN ExpressionLine BY Expression',
+      function() {
+        return {
+          source: $2,
+          guard: $4,
+          step: $6
+        };
+      }),
       o('FORIN Expression BY Expression WHEN Expression',
       function() {
         return {
@@ -1314,6 +1566,30 @@
           guard: $6
         };
       }),
+      o('FORIN ExpressionLine BY Expression WHEN Expression',
+      function() {
+        return {
+          source: $2,
+          step: $4,
+          guard: $6
+        };
+      }),
+      o('FORIN Expression BY ExpressionLine WHEN Expression',
+      function() {
+        return {
+          source: $2,
+          step: $4,
+          guard: $6
+        };
+      }),
+      o('FORIN ExpressionLine BY ExpressionLine WHEN Expression',
+      function() {
+        return {
+          source: $2,
+          step: $4,
+          guard: $6
+        };
+      }),
       o('FORFROM Expression',
       function() {
         return {
@@ -1322,6 +1598,160 @@
         };
       }),
       o('FORFROM Expression WHEN Expression',
+      function() {
+        return {
+          source: $2,
+          guard: $4,
+          from: true
+        };
+      }),
+      o('FORFROM ExpressionLine WHEN Expression',
+      function() {
+        return {
+          source: $2,
+          guard: $4,
+          from: true
+        };
+      })
+    ],
+    ForLineSource: [
+      o('FORIN ExpressionLine',
+      function() {
+        return {
+          source: $2
+        };
+      }),
+      o('FOROF ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          object: true
+        };
+      }),
+      o('FORIN Expression WHEN ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          guard: $4
+        };
+      }),
+      o('FORIN ExpressionLine WHEN ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          guard: $4
+        };
+      }),
+      o('FOROF Expression WHEN ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          guard: $4,
+          object: true
+        };
+      }),
+      o('FOROF ExpressionLine WHEN ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          guard: $4,
+          object: true
+        };
+      }),
+      o('FORIN Expression BY ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          step: $4
+        };
+      }),
+      o('FORIN ExpressionLine BY ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          step: $4
+        };
+      }),
+      o('FORIN Expression WHEN Expression BY ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          guard: $4,
+          step: $6
+        };
+      }),
+      o('FORIN ExpressionLine WHEN Expression BY ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          guard: $4,
+          step: $6
+        };
+      }),
+      o('FORIN Expression WHEN ExpressionLine BY ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          guard: $4,
+          step: $6
+        };
+      }),
+      o('FORIN ExpressionLine WHEN ExpressionLine BY ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          guard: $4,
+          step: $6
+        };
+      }),
+      o('FORIN Expression BY Expression WHEN ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          step: $4,
+          guard: $6
+        };
+      }),
+      o('FORIN ExpressionLine BY Expression WHEN ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          step: $4,
+          guard: $6
+        };
+      }),
+      o('FORIN Expression BY ExpressionLine WHEN ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          step: $4,
+          guard: $6
+        };
+      }),
+      o('FORIN ExpressionLine BY ExpressionLine WHEN ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          step: $4,
+          guard: $6
+        };
+      }),
+      o('FORFROM ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          from: true
+        };
+      }),
+      o('FORFROM Expression WHEN ExpressionLine',
+      function() {
+        return {
+          source: $2,
+          guard: $4,
+          from: true
+        };
+      }),
+      o('FORFROM ExpressionLine WHEN ExpressionLine',
       function() {
         return {
           source: $2,
@@ -1336,12 +1766,23 @@
         return new Switch($2,
       $4);
       }),
+      o('SWITCH ExpressionLine INDENT Whens OUTDENT',
+      function() {
+        return new Switch($2,
+      $4);
+      }),
       o('SWITCH Expression INDENT Whens ELSE Block OUTDENT',
       function() {
         return new Switch($2,
       $4,
       $6);
       }),
+      o('SWITCH ExpressionLine INDENT Whens ELSE Block OUTDENT',
+      function() {
+        return new Switch($2,
+      $4,
+      $6);
+      }),
       o('SWITCH INDENT Whens OUTDENT',
       function() {
         return new Switch(null,
@@ -1423,12 +1864,63 @@
         });
       })
     ],
+    IfBlockLine: [
+      o('IF ExpressionLine Block',
+      function() {
+        return new If($2,
+      $3,
+      {
+          type: $1
+        });
+      }),
+      o('IfBlockLine ELSE IF ExpressionLine Block',
+      function() {
+        return $1.addElse(LOC(3,
+      5)(new If($4,
+      $5,
+      {
+          type: $3
+        })));
+      })
+    ],
+    IfLine: [
+      o('IfBlockLine'),
+      o('IfBlockLine ELSE Block',
+      function() {
+        return $1.addElse($3);
+      }),
+      o('Statement  POST_IF ExpressionLine',
+      function() {
+        return new If($3,
+      LOC(1)(Block.wrap([$1])),
+      {
+          type: $2,
+          statement: true
+        });
+      }),
+      o('Expression POST_IF ExpressionLine',
+      function() {
+        return new If($3,
+      LOC(1)(Block.wrap([$1])),
+      {
+          type: $2,
+          statement: true
+        });
+      })
+    ],
     // Arithmetic and logical operators, working on one or more operands.
     // Here they are grouped by order of precedence. The actual precedence rules
     // are defined at the bottom of the page. It would be shorter if we could
     // combine most of these rules into a single generic *Operand OpSymbol Operand*
     // -type rule, but in order to make the precedence binding possible, separate
     // rules are necessary.
+    OperationLine: [
+      o('UNARY ExpressionLine',
+      function() {
+        return new Op($1,
+      $2);
+      })
+    ],
     Operation: [
       o('UNARY Expression',
       function() {

lib/coffeescript/helpers.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.0.2
+// Generated by CoffeeScript 2.3.0
 (function() {
   // This file contains the common helper functions that we'd like to share among
   // the **Lexer**, **Rewriter**, and the **Nodes**. Merge objects, flatten

lib/coffeescript/index.js

@@ -1,7 +1,7 @@
-// Generated by CoffeeScript 2.0.2
+// Generated by CoffeeScript 2.3.0
 (function() {
   // Node.js Implementation
-  var CoffeeScript, ext, fn, fs, helpers, i, len, path, ref, universalCompile, vm,
+  var CoffeeScript, ext, fs, helpers, i, len, path, ref, universalCompile, vm,
     hasProp = {}.hasOwnProperty;
 
   CoffeeScript = require('./coffeescript');
@@ -137,15 +137,14 @@
   // Throw error with deprecation warning when depending upon implicit `require.extensions` registration
   if (require.extensions) {
     ref = CoffeeScript.FILE_EXTENSIONS;
-    fn = function(ext) {
-      var base;
-      return (base = require.extensions)[ext] != null ? base[ext] : base[ext] = function() {
-        throw new Error(`Use CoffeeScript.register() or require the coffeescript/register module to require ${ext} files.`);
-      };
-    };
     for (i = 0, len = ref.length; i < len; i++) {
       ext = ref[i];
-      fn(ext);
+      (function(ext) {
+        var base;
+        return (base = require.extensions)[ext] != null ? base[ext] : base[ext] = function() {
+          throw new Error(`Use CoffeeScript.register() or require the coffeescript/register module to require ${ext} files.`);
+        };
+      })(ext);
     }
   }
 

lib/coffeescript/lexer.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.0.2
+// Generated by CoffeeScript 2.3.0
 (function() {
   // The CoffeeScript Lexer. Uses a series of token-matching regexes to attempt
   // matches against the beginning of the source code. When a match is found,
@@ -10,8 +10,9 @@
   // where locationData is {first_line, first_column, last_line, last_column}, which is a
   // format that can be fed directly into [Jison](https://github.com/zaach/jison).  These
   // are read by jison in the `parser.lexer` function defined in coffeescript.coffee.
-  var BOM, BOOL, CALLABLE, CODE, COFFEE_ALIASES, COFFEE_ALIAS_MAP, COFFEE_KEYWORDS, COMMENT, COMPARABLE_LEFT_SIDE, COMPARE, COMPOUND_ASSIGN, CSX_ATTRIBUTE, CSX_IDENTIFIER, CSX_INTERPOLATION, HERECOMMENT_ILLEGAL, HEREDOC_DOUBLE, HEREDOC_INDENT, HEREDOC_SINGLE, HEREGEX, HEREGEX_OMIT, HERE_JSTOKEN, IDENTIFIER, INDENTABLE_CLOSERS, INDEXABLE, INSIDE_CSX, INVERSES, JSTOKEN, JS_KEYWORDS, LEADING_BLANK_LINE, LINE_BREAK, LINE_CONTINUER, Lexer, MATH, MULTI_DENT, NOT_REGEX, NUMBER, OPERATOR, POSSIBLY_DIVISION, REGEX, REGEX_FLAGS, REGEX_ILLEGAL, REGEX_INVALID_ESCAPE, RELATION, RESERVED, Rewriter, SHIFT, SIMPLE_STRING_OMIT, STRICT_PROSCRIBED, STRING_DOUBLE, STRING_INVALID_ESCAPE, STRING_OMIT, STRING_SINGLE, STRING_START, TRAILING_BLANK_LINE, TRAILING_SPACES, UNARY, UNARY_MATH, UNFINISHED, UNICODE_CODE_POINT_ESCAPE, VALID_FLAGS, WHITESPACE, attachCommentsToNode, compact, count, invertLiterate, isForFrom, isUnassignable, key, locationDataToString, merge, repeat, starts, throwSyntaxError,
-    indexOf = [].indexOf;
+  var BOM, BOOL, CALLABLE, CODE, COFFEE_ALIASES, COFFEE_ALIAS_MAP, COFFEE_KEYWORDS, COMMENT, COMPARABLE_LEFT_SIDE, COMPARE, COMPOUND_ASSIGN, CSX_ATTRIBUTE, CSX_FRAGMENT_IDENTIFIER, CSX_IDENTIFIER, CSX_INTERPOLATION, HERECOMMENT_ILLEGAL, HEREDOC_DOUBLE, HEREDOC_INDENT, HEREDOC_SINGLE, HEREGEX, HEREGEX_OMIT, HERE_JSTOKEN, IDENTIFIER, INDENTABLE_CLOSERS, INDEXABLE, INSIDE_CSX, INVERSES, JSTOKEN, JS_KEYWORDS, LEADING_BLANK_LINE, LINE_BREAK, LINE_CONTINUER, Lexer, MATH, MULTI_DENT, NOT_REGEX, NUMBER, OPERATOR, POSSIBLY_DIVISION, REGEX, REGEX_FLAGS, REGEX_ILLEGAL, REGEX_INVALID_ESCAPE, RELATION, RESERVED, Rewriter, SHIFT, SIMPLE_STRING_OMIT, STRICT_PROSCRIBED, STRING_DOUBLE, STRING_INVALID_ESCAPE, STRING_OMIT, STRING_SINGLE, STRING_START, TRAILING_BLANK_LINE, TRAILING_SPACES, UNARY, UNARY_MATH, UNFINISHED, UNICODE_CODE_POINT_ESCAPE, VALID_FLAGS, WHITESPACE, attachCommentsToNode, compact, count, invertLiterate, isForFrom, isUnassignable, key, locationDataToString, merge, repeat, starts, throwSyntaxError,
+    indexOf = [].indexOf,
+    slice = [].slice;
 
   ({Rewriter, INVERSES} = require('./rewriter'));
 
@@ -111,7 +112,7 @@
     // referenced as property names here, so you can still do `jQuery.is()` even
     // though `is` means `===` otherwise.
     identifierToken() {
-      var alias, colon, colonOffset, colonToken, id, idLength, inCSXTag, input, match, poppedToken, prev, prevprev, ref, ref1, ref2, ref3, ref4, ref5, ref6, ref7, ref8, regExSuper, regex, sup, tag, tagToken;
+      var alias, colon, colonOffset, colonToken, id, idLength, inCSXTag, input, match, poppedToken, prev, prevprev, ref, ref1, ref10, ref2, ref3, ref4, ref5, ref6, ref7, ref8, ref9, regExSuper, regex, sup, tag, tagToken;
       inCSXTag = this.atCSXTag();
       regex = inCSXTag ? CSX_ATTRIBUTE : IDENTIFIER;
       if (!(match = regex.exec(this.chunk))) {
@@ -199,11 +200,11 @@
       // what CoffeeScript would normally interpret as calls to functions named
       // `get` or `set`, i.e. `get({foo: function () {}})`.
       } else if (tag === 'PROPERTY' && prev) {
-        if (prev.spaced && (ref7 = prev[0], indexOf.call(CALLABLE, ref7) >= 0) && /^[gs]et$/.test(prev[1]) && this.tokens[this.tokens.length - 2][0] !== '.') {
+        if (prev.spaced && (ref7 = prev[0], indexOf.call(CALLABLE, ref7) >= 0) && /^[gs]et$/.test(prev[1]) && this.tokens.length > 1 && ((ref8 = this.tokens[this.tokens.length - 2][0]) !== '.' && ref8 !== '?.' && ref8 !== '@')) {
           this.error(`'${prev[1]}' cannot be used as a keyword, or as a function call without parentheses`, prev[2]);
-        } else {
+        } else if (this.tokens.length > 2) {
           prevprev = this.tokens[this.tokens.length - 2];
-          if (((ref8 = prev[0]) === '@' || ref8 === 'THIS') && prevprev && prevprev.spaced && /^[gs]et$/.test(prevprev[1]) && this.tokens[this.tokens.length - 3][0] !== '.') {
+          if (((ref9 = prev[0]) === '@' || ref9 === 'THIS') && prevprev && prevprev.spaced && /^[gs]et$/.test(prevprev[1]) && ((ref10 = this.tokens[this.tokens.length - 3][0]) !== '.' && ref10 !== '?.' && ref10 !== '@')) {
             this.error(`'${prevprev[1]}' cannot be used as a keyword, or as a function call without parentheses`, prevprev[2]);
           }
         }
@@ -586,16 +587,20 @@
     // Keeps track of the level of indentation, because a single outdent token
     // can close multiple indents, so we need to know how far in we happen to be.
     lineToken(chunk = this.chunk) {
-      var diff, indent, match, minLiteralLength, newIndentLiteral, noNewlines, size;
+      var backslash, diff, indent, match, minLiteralLength, newIndentLiteral, noNewlines, prev, size;
       if (!(match = MULTI_DENT.exec(chunk))) {
         return 0;
       }
       indent = match[0];
-      this.seenFor = false;
-      if (!this.importSpecifierList) {
+      prev = this.prev();
+      backslash = (prev != null ? prev[0] : void 0) === '\\';
+      if (!(backslash && this.seenFor)) {
+        this.seenFor = false;
+      }
+      if (!((backslash && this.seenImport) || this.importSpecifierList)) {
         this.seenImport = false;
       }
-      if (!this.exportSpecifierList) {
+      if (!((backslash && this.seenExport) || this.exportSpecifierList)) {
         this.seenExport = false;
       }
       size = indent.length - 1 - indent.lastIndexOf('\n');
@@ -624,7 +629,9 @@
       }
       if (size > this.indent) {
         if (noNewlines) {
-          this.indebt = size - this.indent;
+          if (!backslash) {
+            this.indebt = size - this.indent;
+          }
           this.suppressNewlines();
           return indent.length;
         }
@@ -741,7 +748,7 @@
       // Check the previous token to detect if attribute is spread.
       prevChar = this.tokens.length > 0 ? this.tokens[this.tokens.length - 1][0] : '';
       if (firstChar === '<') {
-        match = CSX_IDENTIFIER.exec(this.chunk.slice(1));
+        match = CSX_IDENTIFIER.exec(this.chunk.slice(1)) || CSX_FRAGMENT_IDENTIFIER.exec(this.chunk.slice(1));
         // Not the right hand side of an unspaced comparison (i.e. `a<b`).
         if (!(match && (this.csxDepth > 0 || !(prev = this.prev()) || prev.spaced || (ref = prev[0], indexOf.call(COMPARABLE_LEFT_SIDE, ref) < 0)))) {
           return 0;
@@ -793,8 +800,8 @@
               delimiter: '>'
             });
           });
-          match = CSX_IDENTIFIER.exec(this.chunk.slice(end));
-          if (!match || match[0] !== csxTag.name) {
+          match = CSX_IDENTIFIER.exec(this.chunk.slice(end)) || CSX_FRAGMENT_IDENTIFIER.exec(this.chunk.slice(end));
+          if (!match || match[1] !== csxTag.name) {
             this.error(`expected corresponding CSX closing tag for ${csxTag.name}`, csxTag.origin[2]);
           }
           afterTag = end + csxTag.name.length;
@@ -1050,7 +1057,7 @@
         if (braceInterpolator) {
           // Turn the leading and trailing `{` and `}` into parentheses. Unnecessary
           // parentheses will be removed later.
-          open = nested[0], close = nested[nested.length - 1];
+          [open] = nested, [close] = slice.call(nested, -1);
           open[0] = open[1] = '(';
           close[0] = close[1] = ')';
           close.origin = ['', 'end of interpolation', close[2]];
@@ -1075,7 +1082,7 @@
           length: delimiter.length
         });
       }
-      firstToken = tokens[0], lastToken = tokens[tokens.length - 1];
+      [firstToken] = tokens, [lastToken] = slice.call(tokens, -1);
       firstToken[2].first_column -= delimiter.length;
       if (lastToken[1].substr(-1) === '\n') {
         lastToken[2].last_line += 1;
@@ -1176,7 +1183,7 @@
         this.tokens.push(...tokensToPush);
       }
       if (lparen) {
-        lastToken = tokens[tokens.length - 1];
+        [lastToken] = slice.call(tokens, -1);
         lparen.origin = [
           'STRING',
           null,
@@ -1202,7 +1209,7 @@
     // correctly balanced throughout the course of the token stream.
     pair(tag) {
       var lastIndent, prev, ref, ref1, wanted;
-      ref = this.ends, prev = ref[ref.length - 1];
+      ref = this.ends, [prev] = slice.call(ref, -1);
       if (tag !== (wanted = prev != null ? prev.tag : void 0)) {
         if ('OUTDENT' !== wanted) {
           this.error(`unmatched ${tag}`);
@@ -1212,7 +1219,7 @@
         //     el.click((event) ->
         //       el.hide())
 
-        ref1 = this.indents, lastIndent = ref1[ref1.length - 1];
+        ref1 = this.indents, [lastIndent] = slice.call(ref1, -1);
         this.outdentToken(lastIndent, true);
         return this.pair(tag);
       }
@@ -1238,7 +1245,7 @@
       lineCount = count(string, '\n');
       column = this.chunkColumn;
       if (lineCount > 0) {
-        ref = string.split('\n'), lastLine = ref[ref.length - 1];
+        ref = string.split('\n'), [lastLine] = slice.call(ref, -1);
         column = lastLine.length;
       } else {
         column += string.length;
@@ -1279,14 +1286,14 @@
     // Peek at the last tag in the token stream.
     tag() {
       var ref, token;
-      ref = this.tokens, token = ref[ref.length - 1];
+      ref = this.tokens, [token] = slice.call(ref, -1);
       return token != null ? token[0] : void 0;
     }
 
     // Peek at the last value in the token stream.
     value(useOrigin = false) {
       var ref, ref1, token;
-      ref = this.tokens, token = ref[ref.length - 1];
+      ref = this.tokens, [token] = slice.call(ref, -1);
       if (useOrigin && ((token != null ? token.origin : void 0) != null)) {
         return (ref1 = token.origin) != null ? ref1[1] : void 0;
       } else {
@@ -1541,6 +1548,9 @@
   CSX_IDENTIFIER = /^(?![\d<])((?:(?!\s)[\.\-$\w\x7f-\uffff])+)/; // Must not start with `<`.
   // Like `IDENTIFIER`, but includes `-`s and `.`s.
 
+  // Fragment: <></>
+  CSX_FRAGMENT_IDENTIFIER = /^()>/; // Ends immediately with `>`.
+
   CSX_ATTRIBUTE = /^(?!\d)((?:(?!\s)[\-$\w\x7f-\uffff])+)([^\S]*=(?!=))?/; // Like `IDENTIFIER`, but includes `-`s.
   // Is this an attribute with a value?
 
@@ -1600,9 +1610,14 @@
 
   REGEX_FLAGS = /^\w*/;
 
-  VALID_FLAGS = /^(?!.*(.).*\1)[imguy]*$/;
+  VALID_FLAGS = /^(?!.*(.).*\1)[gimsuy]*$/;
 
-  HEREGEX = /^(?:[^\\\/#]|\\[\s\S]|\/(?!\/\/)|\#(?!\{))*/;
+  // Match any character, except those that need special handling below.
+  // Match `\` followed by any character.
+  // Match any `/` except `///`.
+  // Match `#` which is not part of interpolation, e.g. `#{}`.
+  // Comments consume everything until the end of the line, including `///`.
+  HEREGEX = /^(?:[^\\\/#\s]|\\[\s\S]|\/(?!\/\/)|\#(?!\{)|\s+(?:#(?!\{).*)?)*/;
 
   HEREGEX_OMIT = /((?:\\\\)+)|\\(\s)|\s+(?:#.*)?/g; // Consume (and preserve) an even number of backslashes.
   // Preserve escaped whitespace.
@@ -1685,6 +1700,6 @@
   INDENTABLE_CLOSERS = [')', '}', ']'];
 
   // Tokens that, when appearing at the end of a line, suppress a following TERMINATOR/INDENT token
-  UNFINISHED = ['\\', '.', '?.', '?::', 'UNARY', 'MATH', 'UNARY_MATH', '+', '-', '**', 'SHIFT', 'RELATION', 'COMPARE', '&', '^', '|', '&&', '||', 'BIN?', 'EXTENDS', 'DEFAULT'];
+  UNFINISHED = ['\\', '.', '?.', '?::', 'UNARY', 'MATH', 'UNARY_MATH', '+', '-', '**', 'SHIFT', 'RELATION', 'COMPARE', '&', '^', '|', '&&', '||', 'BIN?', 'EXTENDS'];
 
 }).call(this);

lib/coffeescript/optparse.js

@@ -1,7 +1,7 @@
-// Generated by CoffeeScript 2.0.2
+// Generated by CoffeeScript 2.3.0
 (function() {
   var LONG_FLAG, MULTI_FLAG, OPTIONAL, OptionParser, SHORT_FLAG, buildRule, buildRules, normalizeArguments, repeat,
-    slice = [].slice;
+    splice = [].splice;
 
   ({repeat} = require('./helpers'));
 
@@ -44,8 +44,8 @@
       // `--` argument after, because that will fail on Linux (see #3946).
       ({rules, positional} = normalizeArguments(args, this.rules.flagDict));
       options = {};
-      // The `argument` field is added to the rule instance non-destructively by
-      // `normalizeArguments`.
+// The `argument` field is added to the rule instance non-destructively by
+// `normalizeArguments`.
       for (i = 0, len = rules.length; i < len; i++) {
         ({hasArgument, argument, isList, name} = rules[i]);
         if (hasArgument) {
@@ -157,7 +157,7 @@
   };
 
   normalizeArguments = function(args, flagDict) {
-    var arg, argIndex, flag, i, innerOpts, j, k, lastOpt, len, len1, multiFlags, multiOpts, needsArgOpt, positional, ref, rule, rules, singleRule, withArg;
+    var arg, argIndex, flag, i, innerOpts, j, lastOpt, len, len1, multiFlags, multiOpts, needsArgOpt, positional, ref, rule, rules, singleRule, withArg;
     rules = [];
     positional = [];
     needsArgOpt = null;
@@ -187,9 +187,9 @@
           return {rule, flag};
         });
         // Only the last flag in a multi-flag may have an argument.
-        innerOpts = 2 <= multiOpts.length ? slice.call(multiOpts, 0, j = multiOpts.length - 1) : (j = 0, []), lastOpt = multiOpts[j++];
-        for (k = 0, len1 = innerOpts.length; k < len1; k++) {
-          ({rule, flag} = innerOpts[k]);
+        [...innerOpts] = multiOpts, [lastOpt] = splice.call(innerOpts, -1);
+        for (j = 0, len1 = innerOpts.length; j < len1; j++) {
+          ({rule, flag} = innerOpts[j]);
           if (rule.hasArgument) {
             throw new Error(`cannot use option ${flag} in multi-flag ${arg} except as the last option, because it needs an argument`);
           }

lib/coffeescript/register.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.0.2
+// Generated by CoffeeScript 2.3.0
 (function() {
   var CoffeeScript, Module, binary, child_process, ext, findExtension, fork, getRootModule, helpers, i, len, loadFile, path, ref;
 

lib/coffeescript/repl.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.0.2
+// Generated by CoffeeScript 2.3.0
 (function() {
   var CoffeeScript, addHistory, addMultilineHandler, fs, getCommandId, merge, nodeREPL, path, replDefaults, runInContext, sawSIGINT, transpile, updateSyntaxError, vm;
 
@@ -29,7 +29,7 @@
     })(),
     historyMaxInputSize: 10240,
     eval: function(input, context, filename, cb) {
-      var Assign, Block, Call, Code, Literal, Value, ast, err, isAsync, js, referencedVars, result, token, tokens;
+      var Assign, Block, Call, Code, Literal, Value, ast, err, isAsync, js, ref, ref1, referencedVars, result, token, tokens;
       // XXX: multiline hack.
       input = input.replace(/\uFF00/g, '\n');
       // Node's REPL sends the input ending with a newline and then wrapped in
@@ -43,6 +43,13 @@
       try {
         // Tokenize the clean input.
         tokens = CoffeeScript.tokens(input);
+        // Filter out tokens generated just to hold comments.
+        if (tokens.length >= 2 && tokens[0].generated && ((ref = tokens[0].comments) != null ? ref.length : void 0) !== 0 && tokens[0][1] === '' && tokens[1][0] === 'TERMINATOR') {
+          tokens = tokens.slice(2);
+        }
+        if (tokens.length >= 1 && tokens[tokens.length - 1].generated && ((ref1 = tokens[tokens.length - 1].comments) != null ? ref1.length : void 0) !== 0 && tokens[tokens.length - 1][1] === '') {
+          tokens.pop();
+        }
         // Collect referenced variable names just like in `CoffeeScript.compile`.
         referencedVars = (function() {
           var i, len, results;

lib/coffeescript/rewriter.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.0.2
+// Generated by CoffeeScript 2.3.0
 (function() {
   // The CoffeeScript language has a good deal of optional syntax, implicit syntax,
   // and shorthand syntax. This can greatly complicate a grammar and bloat
@@ -218,7 +218,7 @@
       indexOfTag(i, ...pattern) {
         var fuzz, j, k, ref, ref1;
         fuzz = 0;
-        for (j = k = 0, ref = pattern.length; 0 <= ref ? k < ref : k > ref; j = 0 <= ref ? ++k : --k) {
+        for (j = k = 0, ref = pattern.length; (0 <= ref ? k < ref : k > ref); j = 0 <= ref ? ++k : --k) {
           if (pattern[j] == null) {
             continue;
           }
@@ -281,7 +281,7 @@
         stack = [];
         start = null;
         return this.scanTokens(function(token, i, tokens) {
-          var endImplicitCall, endImplicitObject, forward, implicitObjectContinues, inImplicit, inImplicitCall, inImplicitControl, inImplicitObject, isImplicit, isImplicitCall, isImplicitObject, k, newLine, nextTag, nextToken, offset, prevTag, prevToken, ref, ref1, s, sameLine, stackIdx, stackItem, stackTag, stackTop, startIdx, startImplicitCall, startImplicitObject, startsLine, tag;
+          var endImplicitCall, endImplicitObject, forward, implicitObjectContinues, inControlFlow, inImplicit, inImplicitCall, inImplicitControl, inImplicitObject, isImplicit, isImplicitCall, isImplicitObject, k, newLine, nextTag, nextToken, offset, prevTag, prevToken, ref, ref1, ref2, s, sameLine, stackIdx, stackItem, stackTag, stackTop, startIdx, startImplicitCall, startImplicitObject, startsLine, tag;
           [tag] = token;
           [prevTag] = prevToken = i > 0 ? tokens[i - 1] : [];
           [nextTag] = nextToken = i < tokens.length - 1 ? tokens[i + 1] : [];
@@ -420,10 +420,31 @@
             }
             start = stack.pop();
           }
+          inControlFlow = () => {
+            var controlFlow, isFunc, seenFor, tagCurrentLine;
+            seenFor = this.findTagsBackwards(i, ['FOR']) && this.findTagsBackwards(i, ['FORIN', 'FOROF', 'FORFROM']);
+            controlFlow = seenFor || this.findTagsBackwards(i, ['WHILE', 'UNTIL', 'LOOP', 'LEADING_WHEN']);
+            if (!controlFlow) {
+              return false;
+            }
+            isFunc = false;
+            tagCurrentLine = token[2].first_line;
+            this.detectEnd(i, function(token, i) {
+              var ref;
+              return ref = token[0], indexOf.call(LINEBREAKS, ref) >= 0;
+            }, function(token, i) {
+              var first_line;
+              [prevTag, , {first_line}] = tokens[i - 1] || [];
+              return isFunc = tagCurrentLine === first_line && (prevTag === '->' || prevTag === '=>');
+            }, {
+              returnOnNegativeLevel: true
+            });
+            return isFunc;
+          };
           // Recognize standard implicit calls like
           // f a, f() b, f? c, h[0] d etc.
           // Added support for spread dots on the left side: f ...a
-          if ((indexOf.call(IMPLICIT_FUNC, tag) >= 0 && token.spaced || tag === '?' && i > 0 && !tokens[i - 1].spaced) && (indexOf.call(IMPLICIT_CALL, nextTag) >= 0 || (nextTag === '...' && (ref = this.tag(i + 2), indexOf.call(IMPLICIT_CALL, ref) >= 0) && !this.findTagsBackwards(i, ['INDEX_START', '['])) || indexOf.call(IMPLICIT_UNSPACED_CALL, nextTag) >= 0 && !nextToken.spaced && !nextToken.newLine)) {
+          if ((indexOf.call(IMPLICIT_FUNC, tag) >= 0 && token.spaced || tag === '?' && i > 0 && !tokens[i - 1].spaced) && (indexOf.call(IMPLICIT_CALL, nextTag) >= 0 || (nextTag === '...' && (ref = this.tag(i + 2), indexOf.call(IMPLICIT_CALL, ref) >= 0) && !this.findTagsBackwards(i, ['INDEX_START', '['])) || indexOf.call(IMPLICIT_UNSPACED_CALL, nextTag) >= 0 && !nextToken.spaced && !nextToken.newLine) && !inControlFlow()) {
             if (tag === '?') {
               tag = token[0] = 'FUNC_EXIST';
             }
@@ -506,11 +527,11 @@
             }
           }
           newLine = prevTag === 'OUTDENT' || prevToken.newLine;
-          if (indexOf.call(IMPLICIT_END, tag) >= 0 || indexOf.call(CALL_CLOSERS, tag) >= 0 && newLine) {
+          if (indexOf.call(IMPLICIT_END, tag) >= 0 || (indexOf.call(CALL_CLOSERS, tag) >= 0 && newLine) || ((tag === '..' || tag === '...') && this.findTagsBackwards(i, ["INDEX_START"]))) {
             while (inImplicit()) {
               [stackTag, stackIdx, {sameLine, startsLine}] = stackTop();
               // Close implicit calls when reached end of argument list
-              if (inImplicitCall() && prevTag !== ',') {
+              if (inImplicitCall() && prevTag !== ',' || (prevTag === ',' && tag === 'TERMINATOR' && (nextTag == null))) {
                 endImplicitCall();
               // Close implicit objects such as:
               // return a: 1, b: 2 unless true
@@ -539,7 +560,7 @@
 
           //     f a, b: c, d: e, f, g: h: i, j
 
-          if (tag === ',' && !this.looksObjectish(i + 1) && inImplicitObject() && (nextTag !== 'TERMINATOR' || !this.looksObjectish(i + 2))) {
+          if (tag === ',' && !this.looksObjectish(i + 1) && inImplicitObject() && !((ref2 = this.tag(i + 2)) === 'FOROF' || ref2 === 'FORIN') && (nextTag !== 'TERMINATOR' || !this.looksObjectish(i + 2))) {
             // When nextTag is OUTDENT the comma is insignificant and
             // should just be ignored so embed it in the implicit object.
 
@@ -781,18 +802,51 @@
       // newlines within expressions are removed and the indentation tokens of empty
       // blocks are added.
       normalizeLines() {
-        var action, condition, indent, outdent, starter;
+        var action, closeElseTag, condition, ifThens, indent, leading_if_then, leading_switch_when, outdent, starter;
         starter = indent = outdent = null;
+        leading_switch_when = null;
+        leading_if_then = null;
+        // Count `THEN` tags
+        ifThens = [];
         condition = function(token, i) {
           var ref, ref1, ref2, ref3;
-          return token[1] !== ';' && (ref = token[0], indexOf.call(SINGLE_CLOSERS, ref) >= 0) && !(token[0] === 'TERMINATOR' && (ref1 = this.tag(i + 1), indexOf.call(EXPRESSION_CLOSE, ref1) >= 0)) && !(token[0] === 'ELSE' && starter !== 'THEN') && !(((ref2 = token[0]) === 'CATCH' || ref2 === 'FINALLY') && (starter === '->' || starter === '=>')) || (ref3 = token[0], indexOf.call(CALL_CLOSERS, ref3) >= 0) && (this.tokens[i - 1].newLine || this.tokens[i - 1][0] === 'OUTDENT');
+          return token[1] !== ';' && (ref = token[0], indexOf.call(SINGLE_CLOSERS, ref) >= 0) && !(token[0] === 'TERMINATOR' && (ref1 = this.tag(i + 1), indexOf.call(EXPRESSION_CLOSE, ref1) >= 0)) && !(token[0] === 'ELSE' && (starter !== 'THEN' || (leading_if_then || leading_switch_when))) && !(((ref2 = token[0]) === 'CATCH' || ref2 === 'FINALLY') && (starter === '->' || starter === '=>')) || (ref3 = token[0], indexOf.call(CALL_CLOSERS, ref3) >= 0) && (this.tokens[i - 1].newLine || this.tokens[i - 1][0] === 'OUTDENT');
         };
         action = function(token, i) {
+          if (token[0] === 'ELSE' && starter === 'THEN') {
+            ifThens.pop();
+          }
           return this.tokens.splice((this.tag(i - 1) === ',' ? i - 1 : i), 0, outdent);
         };
+        closeElseTag = (tokens, i) => {
+          var lastThen, outdentElse, tlen;
+          tlen = ifThens.length;
+          if (!(tlen > 0)) {
+            return i;
+          }
+          lastThen = ifThens.pop();
+          [, outdentElse] = this.indentation(tokens[lastThen]);
+          // Insert `OUTDENT` to close inner `IF`.
+          outdentElse[1] = tlen * 2;
+          tokens.splice(i, 0, outdentElse);
+          // Insert `OUTDENT` to close outer `IF`.
+          outdentElse[1] = 2;
+          tokens.splice(i + 1, 0, outdentElse);
+          // Remove outdents from the end.
+          this.detectEnd(i + 2, function(token, i) {
+            var ref;
+            return (ref = token[0]) === 'OUTDENT' || ref === 'TERMINATOR';
+          }, function(token, i) {
+            if (this.tag(i) === 'OUTDENT' && this.tag(i + 1) === 'OUTDENT') {
+              return tokens.splice(i, 2);
+            }
+          });
+          return i + 2;
+        };
         return this.scanTokens(function(token, i, tokens) {
-          var j, k, ref, ref1, tag;
+          var conditionTag, j, k, ref, ref1, tag;
           [tag] = token;
+          conditionTag = (tag === '->' || tag === '=>') && this.findTagsBackwards(i, ['IF', 'WHILE', 'FOR', 'UNTIL', 'SWITCH', 'WHEN', 'LEADING_WHEN', '[', 'INDEX_START']) && !(this.findTagsBackwards(i, ['THEN', '..', '...']));
           if (tag === 'TERMINATOR') {
             if (this.tag(i + 1) === 'ELSE' && this.tag(i - 1) !== 'OUTDENT') {
               tokens.splice(i, 1, ...this.indentation());
@@ -817,12 +871,23 @@
             tokens.splice(i + 1, 0, indent, outdent);
             return 1;
           }
-          if (indexOf.call(SINGLE_LINERS, tag) >= 0 && this.tag(i + 1) !== 'INDENT' && !(tag === 'ELSE' && this.tag(i + 1) === 'IF')) {
+          if (indexOf.call(SINGLE_LINERS, tag) >= 0 && this.tag(i + 1) !== 'INDENT' && !(tag === 'ELSE' && this.tag(i + 1) === 'IF') && !conditionTag) {
             starter = tag;
             [indent, outdent] = this.indentation(tokens[i]);
             if (starter === 'THEN') {
               indent.fromThen = true;
             }
+            if (tag === 'THEN') {
+              leading_switch_when = this.findTagsBackwards(i, ['LEADING_WHEN']) && this.tag(i + 1) === 'IF';
+              leading_if_then = this.findTagsBackwards(i, ['IF']) && this.tag(i + 1) === 'IF';
+            }
+            if (tag === 'THEN' && this.findTagsBackwards(i, ['IF'])) {
+              ifThens.push(i);
+            }
+            // `ELSE` tag is not closed.
+            if (tag === 'ELSE' && this.tag(i - 1) !== 'OUTDENT') {
+              i = closeElseTag(tokens, i);
+            }
             tokens.splice(i + 1, 0, indent);
             this.detectEnd(i + 2, condition, action);
             if (tag === 'THEN') {
@@ -886,7 +951,7 @@
 
     return Rewriter;
 
-  })();
+  }).call(this);
 
   // Constants
   // ---------

lib/coffeescript/scope.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.0.2
+// Generated by CoffeeScript 2.3.0
 (function() {
   // The **Scope** class regulates lexical scoping within CoffeeScript. As you
   // generate code, you create a tree of scopes in the same shape as the nested

lib/coffeescript/sourcemap.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.0.2
+// Generated by CoffeeScript 2.3.0
 (function() {
   // Source maps allow JavaScript runtimes to match running JavaScript back to
   // the original source code that corresponds to it. This can be minified
@@ -203,7 +203,7 @@
 
     return SourceMap;
 
-  })();
+  }).call(this);
 
   // Our API for source maps is just the `SourceMap` class.
   module.exports = SourceMap;

package.json

@@ -8,7 +8,7 @@
     "compiler"
   ],
   "author": "Jeremy Ashkenas",
-  "version": "2.0.2",
+  "version": "2.3.0",
   "license": "MIT",
   "engines": {
     "node": ">=6"
@@ -39,17 +39,17 @@
     "url": "git://github.com/jashkenas/coffeescript.git"
   },
   "devDependencies": {
-    "babel-core": "~6.26.0",
+    "babel-core": "~6.26.2",
     "babel-preset-babili": "~0.1.4",
-    "babel-preset-env": "~1.6.0",
-    "babel-preset-minify": "^0.2.0",
-    "codemirror": "^5.29.0",
-    "docco": "~0.7.0",
+    "babel-preset-env": "~1.6.1",
+    "babel-preset-minify": "^0.4.0",
+    "codemirror": "^5.37.0",
+    "docco": "~0.8.0",
     "highlight.js": "~9.12.0",
     "jison": ">=0.4.18",
-    "markdown-it": "~8.4.0",
-    "underscore": "~1.8.3",
-    "webpack": "~3.6.0"
+    "markdown-it": "~8.4.1",
+    "underscore": "~1.9.0",
+    "webpack": "~4.6.0"
   },
   "dependencies": {}
 }

src/coffeescript.coffee

@@ -140,12 +140,14 @@ exports.compile = compile = withPrettyErrors (code, options = {}) ->
     transpiler = options.transpile.transpile
     delete options.transpile.transpile
 
+    transpilerOptions = Object.assign {}, options.transpile
+
     # See https://github.com/babel/babel/issues/827#issuecomment-77573107:
     # Babel can take a v3 source map object as input in `inputSourceMap`
     # and it will return an *updated* v3 source map object in its output.
-    if v3SourceMap and not options.transpile.inputSourceMap?
-      options.transpile.inputSourceMap = v3SourceMap
-    transpilerOutput = transpiler js, options.transpile
+    if v3SourceMap and not transpilerOptions.inputSourceMap?
+      transpilerOptions.inputSourceMap = v3SourceMap
+    transpilerOutput = transpiler js, transpilerOptions
     js = transpilerOutput.code
     if v3SourceMap and transpilerOutput.map
       v3SourceMap = transpilerOutput.map

src/command.coffee

@@ -401,7 +401,7 @@ mkdirp = (dir, fn) ->
 # If `generatedSourceMap` is provided, this will write a `.js.map` file into the
 # same directory as the `.js` file.
 writeJs = (base, sourcePath, js, jsPath, generatedSourceMap = null) ->
-  sourceMapPath = outputPath sourcePath, base, ".js.map"
+  sourceMapPath = "#{jsPath}.map"
   jsDir  = path.dirname jsPath
   compile = ->
     if opts.compile

src/grammar.coffee

@@ -89,6 +89,7 @@ grammar =
   # grammar.
   Line: [
     o 'Expression'
+    o 'ExpressionLine'
     o 'Statement'
     o 'FuncDirective'
   ]
@@ -125,6 +126,15 @@ grammar =
     o 'Yield'
   ]
 
+  # Expressions which are written in single line and would otherwise require being
+  # wrapped in braces: E.g `a = b if do -> f a is 1`, `if f (a) -> a*2 then ...`,
+  # `for x in do (obj) -> f obj when x > 8 then f x`
+  ExpressionLine: [
+    o 'CodeLine'
+    o 'IfLine'
+    o 'OperationLine'
+  ]
+
   Yield: [
     o 'YIELD',                                  -> new Op $1, new Value new Literal ''
     o 'YIELD Expression',                       -> new Op $1, $2
@@ -210,6 +220,7 @@ grammar =
 
   ObjAssignable: [
     o 'SimpleObjAssignable'
+    o '[ Expression ]',          -> new Value new ComputedPropertyName $2
     o 'AlphaNumeric'
   ]
 
@@ -266,6 +277,13 @@ grammar =
     o 'FuncGlyph Block',                                 -> new Code [], $2, $1
   ]
 
+  # The Codeline is the **Code** node with **Line** instead of indented **Block**.
+  CodeLine: [
+    o 'PARAM_START ParamList PARAM_END FuncGlyph Line', -> new Code $2, LOC(5)(Block.wrap [$5]), $4,
+                                                              LOC(1)(new Literal $1)
+    o 'FuncGlyph Line',                                 -> new Code [], LOC(2)(Block.wrap [$2]), $1
+  ]
+
   # CoffeeScript has two different symbols for functions. `->` is for ordinary
   # functions, and `=>` is for functions bound to the current value of *this*.
   FuncGlyph: [
@@ -439,6 +457,7 @@ grammar =
     o 'EXPORT Identifier = INDENT Expression OUTDENT',       -> new ExportNamedDeclaration new Assign $2, $5, null,
                                                                                                       moduleDeclaration: 'export'
     o 'EXPORT DEFAULT Expression',                           -> new ExportDefaultDeclaration $3
+    o 'EXPORT DEFAULT INDENT Object OUTDENT',                -> new ExportDefaultDeclaration new Value $4
     o 'EXPORT EXPORT_ALL FROM String',                       -> new ExportAllDeclaration new Literal($2), $4
     o 'EXPORT { ExportSpecifierList OptComma } FROM String', -> new ExportNamedDeclaration new ExportSpecifierList($3), $7
   ]
@@ -492,7 +511,8 @@ grammar =
   # The array literal.
   Array: [
     o '[ ]',                                    -> new Arr []
-    o '[ ArgList OptComma ]',                   -> new Arr $2
+    o '[ Elisions ]',                           -> new Arr $2
+    o '[ ArgElisionList OptElisions ]',         -> new Arr [].concat $2, $3
   ]
 
   # Inclusive and exclusive range dots.
@@ -503,19 +523,21 @@ grammar =
 
   # The CoffeeScript range literal.
   Range: [
-    o '[ Expression RangeDots Expression ]',    -> new Range $2, $4, $3
+    o '[ Expression RangeDots Expression ]',      -> new Range $2, $4, $3
+    o '[ ExpressionLine RangeDots Expression ]',  -> new Range $2, $4, $3
   ]
 
   # Array slice literals.
   Slice: [
     o 'Expression RangeDots Expression',        -> new Range $1, $3, $2
     o 'Expression RangeDots',                   -> new Range $1, null, $2
+    o 'ExpressionLine RangeDots Expression',    -> new Range $1, $3, $2
+    o 'ExpressionLine RangeDots',               -> new Range $1, null, $2
     o 'RangeDots Expression',                   -> new Range null, $2, $1
     o 'RangeDots',                              -> new Range null, null, $1
   ]
 
-  # The **ArgList** is both the list of objects passed into a function call,
-  # as well as the contents of an array literal
+  # The **ArgList** is the list of objects passed into a function call
   # (i.e. comma-separated expressions). Newlines work as well.
   ArgList: [
     o 'Arg',                                              -> [$1]
@@ -528,16 +550,48 @@ grammar =
   # Valid arguments are Blocks or Splats.
   Arg: [
     o 'Expression'
+    o 'ExpressionLine'
     o 'Splat'
     o '...',                                     -> new Expansion
   ]
 
+  # The **ArgElisionList** is the list of objects, contents of an array literal
+  # (i.e. comma-separated expressions and elisions). Newlines work as well.
+  ArgElisionList: [
+    o 'ArgElision'
+    o 'ArgElisionList , ArgElision',                                          -> $1.concat $3
+    o 'ArgElisionList OptElisions TERMINATOR ArgElision',                     -> $1.concat $2, $4
+    o 'INDENT ArgElisionList OptElisions OUTDENT',                            -> $2.concat $3
+    o 'ArgElisionList OptElisions INDENT ArgElisionList OptElisions OUTDENT', -> $1.concat $2, $4, $5
+  ]
+
+  ArgElision: [
+    o 'Arg',                  -> [$1]
+    o 'Elisions Arg',         -> $1.concat $2
+  ]
+
+  OptElisions: [
+    o 'OptComma',             -> []
+    o ', Elisions',           -> [].concat $2
+  ]
+
+  Elisions: [
+    o 'Elision',              -> [$1]
+    o 'Elisions Elision',     -> $1.concat $2
+  ]
+
+  Elision: [
+    o ',',                    -> new Elision
+  ]
+
   # Just simple, comma-separated, required arguments (no fancy syntax). We need
   # this to be separate from the **ArgList** for use in **Switch** blocks, where
   # having the newlines wouldn't make sense.
   SimpleArgs: [
     o 'Expression'
+    o 'ExpressionLine'
     o 'SimpleArgs , Expression',                -> [].concat $1, $3
+    o 'SimpleArgs , ExpressionLine',            -> [].concat $1, $3
   ]
 
   # The variants of *try/catch/finally* exception handling blocks.
@@ -571,17 +625,27 @@ grammar =
   ]
 
   # The condition portion of a while loop.
+  WhileLineSource: [
+    o 'WHILE ExpressionLine',                       -> new While $2
+    o 'WHILE ExpressionLine WHEN ExpressionLine',   -> new While $2, guard: $4
+    o 'UNTIL ExpressionLine',                       -> new While $2, invert: true
+    o 'UNTIL ExpressionLine WHEN ExpressionLine',   -> new While $2, invert: true, guard: $4
+  ]
+
   WhileSource: [
     o 'WHILE Expression',                       -> new While $2
     o 'WHILE Expression WHEN Expression',       -> new While $2, guard: $4
+    o 'WHILE ExpressionLine WHEN Expression',   -> new While $2, guard: $4
     o 'UNTIL Expression',                       -> new While $2, invert: true
     o 'UNTIL Expression WHEN Expression',       -> new While $2, invert: true, guard: $4
+    o 'UNTIL ExpressionLine WHEN Expression',   -> new While $2, invert: true, guard: $4
   ]
 
   # The while loop can either be normal, with a block of expressions to execute,
   # or postfix, with a single expression. There is no do..while.
   While: [
     o 'WhileSource Block',                      -> $1.addBody $2
+    o 'WhileLineSource Block',                  -> $1.addBody $2
     o 'Statement  WhileSource',                 -> $2.addBody LOC(1) Block.wrap([$1])
     o 'Expression WhileSource',                 -> $2.addBody LOC(1) Block.wrap([$1])
     o 'Loop',                                   -> $1
@@ -596,20 +660,31 @@ grammar =
   # Comprehensions can either be normal, with a block of expressions to execute,
   # or postfix, with a single expression.
   For: [
-    o 'Statement  ForBody',                     -> new For $1, $2
-    o 'Expression ForBody',                     -> new For $1, $2
-    o 'ForBody    Block',                       -> new For $2, $1
+    o 'Statement    ForBody',  -> $2.addBody $1
+    o 'Expression   ForBody',  -> $2.addBody $1
+    o 'ForBody      Block',    -> $1.addBody $2
+    o 'ForLineBody  Block',    -> $1.addBody $2
   ]
 
   ForBody: [
-    o 'FOR Range',                              -> source: (LOC(2) new Value($2))
-    o 'FOR Range BY Expression',                -> source: (LOC(2) new Value($2)), step: $4
-    o 'ForStart ForSource',                     -> $2.own = $1.own; $2.ownTag = $1.ownTag; $2.name = $1[0]; $2.index = $1[1]; $2
+    o 'FOR Range',                -> new For [], source: (LOC(2) new Value($2))
+    o 'FOR Range BY Expression',  -> new For [], source: (LOC(2) new Value($2)), step: $4
+    o 'ForStart ForSource',       -> $1.addSource $2
+  ]
+
+  ForLineBody: [
+    o 'FOR Range BY ExpressionLine',  -> new For [], source: (LOC(2) new Value($2)), step: $4
+    o 'ForStart ForLineSource',       -> $1.addSource $2
   ]
 
   ForStart: [
-    o 'FOR ForVariables',                       -> $2
-    o 'FOR OWN ForVariables',                   -> $3.own = yes; $3.ownTag = (LOC(2) new Literal($2)); $3
+    o 'FOR ForVariables',        -> new For [], name: $2[0], index: $2[1]
+    o 'FOR AWAIT ForVariables',  ->
+        [name, index] = $3
+        new For [], {name, index, await: yes, awaitTag: (LOC(2) new Literal($2))}
+    o 'FOR OWN ForVariables',    ->
+        [name, index] = $3
+        new For [], {name, index, own: yes, ownTag: (LOC(2) new Literal($2))}
   ]
 
   # An array of all accepted values for a variable inside the loop.
@@ -633,22 +708,56 @@ grammar =
   # clause. If it's an array comprehension, you can also choose to step through
   # in fixed-size increments.
   ForSource: [
-    o 'FORIN Expression',                               -> source: $2
-    o 'FOROF Expression',                               -> source: $2, object: yes
-    o 'FORIN Expression WHEN Expression',               -> source: $2, guard: $4
-    o 'FOROF Expression WHEN Expression',               -> source: $2, guard: $4, object: yes
-    o 'FORIN Expression BY Expression',                 -> source: $2, step:  $4
-    o 'FORIN Expression WHEN Expression BY Expression', -> source: $2, guard: $4, step: $6
-    o 'FORIN Expression BY Expression WHEN Expression', -> source: $2, step:  $4, guard: $6
-    o 'FORFROM Expression',                             -> source: $2, from: yes
-    o 'FORFROM Expression WHEN Expression',             -> source: $2, guard: $4, from: yes
+    o 'FORIN Expression',                                           -> source: $2
+    o 'FOROF Expression',                                           -> source: $2, object: yes
+    o 'FORIN Expression WHEN Expression',                           -> source: $2, guard: $4
+    o 'FORIN ExpressionLine WHEN Expression',                       -> source: $2, guard: $4
+    o 'FOROF Expression WHEN Expression',                           -> source: $2, guard: $4, object: yes
+    o 'FOROF ExpressionLine WHEN Expression',                       -> source: $2, guard: $4, object: yes
+    o 'FORIN Expression BY Expression',                             -> source: $2, step:  $4
+    o 'FORIN ExpressionLine BY Expression',                         -> source: $2, step:  $4
+    o 'FORIN Expression WHEN Expression BY Expression',             -> source: $2, guard: $4, step: $6
+    o 'FORIN ExpressionLine WHEN Expression BY Expression',         -> source: $2, guard: $4, step: $6
+    o 'FORIN Expression WHEN ExpressionLine BY Expression',         -> source: $2, guard: $4, step: $6
+    o 'FORIN ExpressionLine WHEN ExpressionLine BY Expression',     -> source: $2, guard: $4, step: $6
+    o 'FORIN Expression BY Expression WHEN Expression',             -> source: $2, step:  $4, guard: $6
+    o 'FORIN ExpressionLine BY Expression WHEN Expression',         -> source: $2, step:  $4, guard: $6
+    o 'FORIN Expression BY ExpressionLine WHEN Expression',         -> source: $2, step:  $4, guard: $6
+    o 'FORIN ExpressionLine BY ExpressionLine WHEN Expression',     -> source: $2, step:  $4, guard: $6
+    o 'FORFROM Expression',                                         -> source: $2, from: yes
+    o 'FORFROM Expression WHEN Expression',                         -> source: $2, guard: $4, from: yes
+    o 'FORFROM ExpressionLine WHEN Expression',                     -> source: $2, guard: $4, from: yes
+  ]
+
+  ForLineSource: [
+    o 'FORIN ExpressionLine',                                       -> source: $2
+    o 'FOROF ExpressionLine',                                       -> source: $2, object: yes
+    o 'FORIN Expression WHEN ExpressionLine',                       -> source: $2, guard: $4
+    o 'FORIN ExpressionLine WHEN ExpressionLine',                   -> source: $2, guard: $4
+    o 'FOROF Expression WHEN ExpressionLine',                       -> source: $2, guard: $4, object: yes
+    o 'FOROF ExpressionLine WHEN ExpressionLine',                   -> source: $2, guard: $4, object: yes
+    o 'FORIN Expression BY ExpressionLine',                         -> source: $2, step:  $4
+    o 'FORIN ExpressionLine BY ExpressionLine',                     -> source: $2, step:  $4
+    o 'FORIN Expression WHEN Expression BY ExpressionLine',         -> source: $2, guard: $4, step: $6
+    o 'FORIN ExpressionLine WHEN Expression BY ExpressionLine',     -> source: $2, guard: $4, step: $6
+    o 'FORIN Expression WHEN ExpressionLine BY ExpressionLine',     -> source: $2, guard: $4, step: $6
+    o 'FORIN ExpressionLine WHEN ExpressionLine BY ExpressionLine', -> source: $2, guard: $4, step: $6
+    o 'FORIN Expression BY Expression WHEN ExpressionLine',         -> source: $2, step:  $4, guard: $6
+    o 'FORIN ExpressionLine BY Expression WHEN ExpressionLine',     -> source: $2, step:  $4, guard: $6
+    o 'FORIN Expression BY ExpressionLine WHEN ExpressionLine',     -> source: $2, step:  $4, guard: $6
+    o 'FORIN ExpressionLine BY ExpressionLine WHEN ExpressionLine', -> source: $2, step:  $4, guard: $6
+    o 'FORFROM ExpressionLine',                                     -> source: $2, from: yes
+    o 'FORFROM Expression WHEN ExpressionLine',                     -> source: $2, guard: $4, from: yes
+    o 'FORFROM ExpressionLine WHEN ExpressionLine',                 -> source: $2, guard: $4, from: yes
   ]
 
   Switch: [
-    o 'SWITCH Expression INDENT Whens OUTDENT',            -> new Switch $2, $4
-    o 'SWITCH Expression INDENT Whens ELSE Block OUTDENT', -> new Switch $2, $4, $6
-    o 'SWITCH INDENT Whens OUTDENT',                       -> new Switch null, $3
-    o 'SWITCH INDENT Whens ELSE Block OUTDENT',            -> new Switch null, $3, $5
+    o 'SWITCH Expression INDENT Whens OUTDENT',                -> new Switch $2, $4
+    o 'SWITCH ExpressionLine INDENT Whens OUTDENT',            -> new Switch $2, $4
+    o 'SWITCH Expression INDENT Whens ELSE Block OUTDENT',     -> new Switch $2, $4, $6
+    o 'SWITCH ExpressionLine INDENT Whens ELSE Block OUTDENT', -> new Switch $2, $4, $6
+    o 'SWITCH INDENT Whens OUTDENT',                           -> new Switch null, $3
+    o 'SWITCH INDENT Whens ELSE Block OUTDENT',                -> new Switch null, $3, $5
   ]
 
   Whens: [
@@ -679,12 +788,28 @@ grammar =
     o 'Expression POST_IF Expression',          -> new If $3, LOC(1)(Block.wrap [$1]), type: $2, statement: true
   ]
 
+  IfBlockLine: [
+    o 'IF ExpressionLine Block',                  -> new If $2, $3, type: $1
+    o 'IfBlockLine ELSE IF ExpressionLine Block', -> $1.addElse LOC(3,5) new If $4, $5, type: $3
+  ]
+
+  IfLine: [
+    o 'IfBlockLine'
+    o 'IfBlockLine ELSE Block',               -> $1.addElse $3
+    o 'Statement  POST_IF ExpressionLine',    -> new If $3, LOC(1)(Block.wrap [$1]), type: $2, statement: true
+    o 'Expression POST_IF ExpressionLine',    -> new If $3, LOC(1)(Block.wrap [$1]), type: $2, statement: true
+  ]
+
   # Arithmetic and logical operators, working on one or more operands.
   # Here they are grouped by order of precedence. The actual precedence rules
   # are defined at the bottom of the page. It would be shorter if we could
   # combine most of these rules into a single generic *Operand OpSymbol Operand*
   # -type rule, but in order to make the precedence binding possible, separate
   # rules are necessary.
+  OperationLine: [
+    o 'UNARY ExpressionLine',                   -> new Op $1, $2
+  ]
+
   Operation: [
     o 'UNARY Expression',                       -> new Op $1 , $2
     o 'UNARY_MATH Expression',                  -> new Op $1 , $2

src/lexer.coffee

@@ -192,13 +192,17 @@ exports.Lexer = class Lexer
     # what CoffeeScript would normally interpret as calls to functions named
     # `get` or `set`, i.e. `get({foo: function () {}})`.
     else if tag is 'PROPERTY' and prev
-      if prev.spaced and prev[0] in CALLABLE and /^[gs]et$/.test(prev[1]) and @tokens[@tokens.length - 2][0] isnt '.'
-        @error "'#{prev[1]}' cannot be used as a keyword, or as a function call without parentheses", prev[2]
-      else
+      if prev.spaced and prev[0] in CALLABLE and /^[gs]et$/.test(prev[1]) and
+         @tokens.length > 1 and @tokens[@tokens.length - 2][0] not in ['.', '?.', '@']
+        @error "'#{prev[1]}' cannot be used as a keyword, or as a function call
+        without parentheses", prev[2]
+      else if @tokens.length > 2
         prevprev = @tokens[@tokens.length - 2]
-        if prev[0] in ['@', 'THIS'] and prevprev and prevprev.spaced and /^[gs]et$/.test(prevprev[1]) and
-        @tokens[@tokens.length - 3][0] isnt '.'
-          @error "'#{prevprev[1]}' cannot be used as a keyword, or as a function call without parentheses", prevprev[2]
+        if prev[0] in ['@', 'THIS'] and prevprev and prevprev.spaced and
+           /^[gs]et$/.test(prevprev[1]) and
+           @tokens[@tokens.length - 3][0] not in ['.', '?.', '@']
+          @error "'#{prevprev[1]}' cannot be used as a keyword, or as a
+          function call without parentheses", prevprev[2]
 
     if tag is 'IDENTIFIER' and id in RESERVED
       @error "reserved word '#{id}'", length: id.length
@@ -449,9 +453,11 @@ exports.Lexer = class Lexer
     return 0 unless match = MULTI_DENT.exec chunk
     indent = match[0]
 
-    @seenFor = no
-    @seenImport = no unless @importSpecifierList
-    @seenExport = no unless @exportSpecifierList
+    prev = @prev()
+    backslash = prev?[0] is '\\'
+    @seenFor = no unless backslash and @seenFor
+    @seenImport = no unless (backslash and @seenImport) or @importSpecifierList
+    @seenExport = no unless (backslash and @seenExport) or @exportSpecifierList
 
     size = indent.length - 1 - indent.lastIndexOf '\n'
     noNewlines = @unfinished()
@@ -472,7 +478,7 @@ exports.Lexer = class Lexer
 
     if size > @indent
       if noNewlines
-        @indebt = size - @indent
+        @indebt = size - @indent unless backslash
         @suppressNewlines()
         return indent.length
       unless @tokens.length
@@ -556,7 +562,7 @@ exports.Lexer = class Lexer
     # Check the previous token to detect if attribute is spread.
     prevChar = if @tokens.length > 0 then @tokens[@tokens.length - 1][0] else ''
     if firstChar is '<'
-      match = CSX_IDENTIFIER.exec @chunk[1...]
+      match = CSX_IDENTIFIER.exec(@chunk[1...]) or CSX_FRAGMENT_IDENTIFIER.exec(@chunk[1...])
       return 0 unless match and (
         @csxDepth > 0 or
         # Not the right hand side of an unspaced comparison (i.e. `a<b`).
@@ -596,8 +602,8 @@ exports.Lexer = class Lexer
           @matchWithInterpolations INSIDE_CSX, '>', '</', CSX_INTERPOLATION
         @mergeInterpolationTokens tokens, {delimiter: '"'}, (value, i) =>
           @formatString value, delimiter: '>'
-        match = CSX_IDENTIFIER.exec @chunk[end...]
-        if not match or match[0] isnt csxTag.name
+        match = CSX_IDENTIFIER.exec(@chunk[end...]) or CSX_FRAGMENT_IDENTIFIER.exec(@chunk[end...])
+        if not match or match[1] isnt csxTag.name
           @error "expected corresponding CSX closing tag for #{csxTag.name}",
             csxTag.origin[2]
         afterTag = end + csxTag.name.length
@@ -1178,6 +1184,11 @@ CSX_IDENTIFIER = /// ^
   ( (?: (?!\s)[\.\-$\w\x7f-\uffff] )+ ) # Like `IDENTIFIER`, but includes `-`s and `.`s.
 ///
 
+# Fragment: <></>
+CSX_FRAGMENT_IDENTIFIER = /// ^
+  ()> # Ends immediately with `>`.
+///
+
 CSX_ATTRIBUTE = /// ^
   (?!\d)
   ( (?: (?!\s)[\-$\w\x7f-\uffff] )+ ) # Like `IDENTIFIER`, but includes `-`s.
@@ -1250,9 +1261,22 @@ REGEX = /// ^
 ///
 
 REGEX_FLAGS  = /^\w*/
-VALID_FLAGS  = /^(?!.*(.).*\1)[imguy]*$/
+VALID_FLAGS  = /^(?!.*(.).*\1)[gimsuy]*$/
 
-HEREGEX      = /// ^(?: [^\\/#] | \\[\s\S] | /(?!//) | \#(?!\{) )* ///
+HEREGEX      = /// ^
+  (?:
+      # Match any character, except those that need special handling below.
+      [^\\/#\s]
+      # Match `\` followed by any character.
+    | \\[\s\S]
+      # Match any `/` except `///`.
+    | /(?!//)
+      # Match `#` which is not part of interpolation, e.g. `#{}`.
+    | \#(?!\{)
+      # Comments consume everything until the end of the line, including `///`.
+    | \s+(?:#(?!\{).*)?
+  )*
+///
 
 HEREGEX_OMIT = ///
     ((?:\\\\)+)     # Consume (and preserve) an even number of backslashes.
@@ -1354,4 +1378,4 @@ INDENTABLE_CLOSERS = [')', '}', ']']
 # Tokens that, when appearing at the end of a line, suppress a following TERMINATOR/INDENT token
 UNFINISHED = ['\\', '.', '?.', '?::', 'UNARY', 'MATH', 'UNARY_MATH', '+', '-',
            '**', 'SHIFT', 'RELATION', 'COMPARE', '&', '^', '|', '&&', '||',
-           'BIN?', 'EXTENDS', 'DEFAULT']
+           'BIN?', 'EXTENDS']

src/nodes.coffee

@@ -765,6 +765,10 @@ exports.CSXTag = class CSXTag extends IdentifierLiteral
 exports.PropertyName = class PropertyName extends Literal
   isAssignable: YES
 
+exports.ComputedPropertyName = class ComputedPropertyName extends PropertyName
+  compileNode: (o) ->
+    [@makeCode('['), @value.compileToFragments(o, LEVEL_LIST)..., @makeCode(']')]
+
 exports.StatementLiteral = class StatementLiteral extends Literal
   isStatement: YES
 
@@ -910,6 +914,10 @@ exports.Value = class Value extends Base
     return no if @properties.length
     (@base instanceof Obj) and (not onlyGenerated or @base.generated)
 
+  isElision: ->
+    return no unless @base instanceof Arr
+    @base.hasElision()
+
   isSplice: ->
     [..., lastProp] = @properties
     lastProp instanceof Slice
@@ -948,11 +956,21 @@ exports.Value = class Value extends Base
   compileNode: (o) ->
     @base.front = @front
     props = @properties
-    fragments = @base.compileToFragments o, (if props.length then LEVEL_ACCESS else null)
+    if props.length and @base.cached?
+      # Cached fragments enable correct order of the compilation,
+      # and reuse of variables in the scope.
+      # Example:
+      # `a(x = 5).b(-> x = 6)` should compile in the same order as
+      # `a(x = 5); b(-> x = 6)`
+      # (see issue #4437, https://github.com/jashkenas/coffeescript/issues/4437)
+      fragments = @base.cached
+    else
+      fragments = @base.compileToFragments o, (if props.length then LEVEL_ACCESS else null)
     if props.length and SIMPLENUM.test fragmentsToText fragments
       fragments.push @makeCode '.'
     for prop in props
       fragments.push (prop.compileToFragments o)...
+
     fragments
 
   # Unfold a soak into an `If`: `a?.b` -> `a.b if a?`
@@ -1112,6 +1130,19 @@ exports.Call = class Call extends Base
     return @compileCSX o if @csx
     @variable?.front = @front
     compiledArgs = []
+    # If variable is `Accessor` fragments are cached and used later
+    # in `Value::compileNode` to ensure correct order of the compilation,
+    # and reuse of variables in the scope.
+    # Example:
+    # `a(x = 5).b(-> x = 6)` should compile in the same order as
+    # `a(x = 5); b(-> x = 6)`
+    # (see issue #4437, https://github.com/jashkenas/coffeescript/issues/4437)
+    varAccess = @variable?.properties?[0] instanceof Access
+    argCode = (arg for arg in (@args || []) when arg instanceof Code)
+    if argCode.length > 0 and varAccess and not @variable.base.cached
+      [cache] = @variable.base.cache o, LEVEL_ACCESS, -> no
+      @variable.base.cached = cache
+
     for arg, argIndex in @args
       if argIndex then compiledArgs.push @makeCode ", "
       compiledArgs.push (arg.compileToFragments o, LEVEL_LIST)...
@@ -1317,20 +1348,35 @@ exports.Range = class Range extends Base
     idx      = del o, 'index'
     idxName  = del o, 'name'
     namedIndex = idxName and idxName isnt idx
-    varPart  = "#{idx} = #{@fromC}"
+    varPart  =
+      if known and not namedIndex
+        "var #{idx} = #{@fromC}"
+      else
+        "#{idx} = #{@fromC}"
     varPart += ", #{@toC}" if @toC isnt @toVar
     varPart += ", #{@step}" if @step isnt @stepVar
     [lt, gt] = ["#{idx} <#{@equals}", "#{idx} >#{@equals}"]
 
     # Generate the condition.
-    condPart = if @stepNum?
-      if @stepNum > 0 then "#{lt} #{@toVar}" else "#{gt} #{@toVar}"
-    else if known
-      [from, to] = [@fromNum, @toNum]
-      if from <= to then "#{lt} #{to}" else "#{gt} #{to}"
-    else
-      cond = if @stepVar then "#{@stepVar} > 0" else "#{@fromVar} <= #{@toVar}"
-      "#{cond} ? #{lt} #{@toVar} : #{gt} #{@toVar}"
+    [from, to] = [@fromNum, @toNum]
+    # Always check if the `step` isn't zero to avoid the infinite loop.
+    stepNotZero = "#{ @stepNum ? @stepVar } !== 0"
+    stepCond = "#{ @stepNum ? @stepVar } > 0"
+    lowerBound = "#{lt} #{ if known then to else @toVar }"
+    upperBound = "#{gt} #{ if known then to else @toVar }"
+    condPart =
+      if @step?
+        if @stepNum? and @stepNum isnt 0
+          if @stepNum > 0 then "#{lowerBound}" else "#{upperBound}"
+        else
+          "#{stepNotZero} && (#{stepCond} ? #{lowerBound} : #{upperBound})"
+      else
+        if known
+          "#{ if from <= to then lt else gt } #{to}"
+        else
+          "(#{@fromVar} <= #{@toVar} ? #{lowerBound} : #{upperBound})"
+
+    cond = if @stepVar then "#{@stepVar} > 0" else "#{@fromVar} <= #{@toVar}"
 
     # Generate the step.
     stepPart = if @stepVar
@@ -1361,9 +1407,9 @@ exports.Range = class Range extends Base
       range.pop() if @exclusive
       return [@makeCode "[#{ range.join(', ') }]"]
     idt    = @tab + TAB
-    i      = o.scope.freeVariable 'i', single: true
-    result = o.scope.freeVariable 'results'
-    pre    = "\n#{idt}#{result} = [];"
+    i      = o.scope.freeVariable 'i', single: true, reserve: no
+    result = o.scope.freeVariable 'results', reserve: no
+    pre    = "\n#{idt}var #{result} = [];"
     if known
       o.index = i
       body    = fragmentsToText @compileNode o
@@ -1393,8 +1439,12 @@ exports.Slice = class Slice extends Base
   # `9e9` should be safe because `9e9` > `2**32`, the max array length.
   compileNode: (o) ->
     {to, from} = @range
-    fromCompiled = from and from.compileToFragments(o, LEVEL_PAREN) or [@makeCode '0']
-    # TODO: jwalton - move this into the 'if'?
+    # Handle an expression in the property access, e.g. `a[!b in c..]`.
+    if from?.shouldCache()
+      from = new Value new Parens from
+    if to?.shouldCache()
+      to = new Value new Parens to
+    fromCompiled = from?.compileToFragments(o, LEVEL_PAREN) or [@makeCode '0']
     if to
       compiled     = to.compileToFragments o, LEVEL_PAREN
       compiledText = fragmentsToText compiled
@@ -1425,7 +1475,9 @@ exports.Obj = class Obj extends Base
       message = isUnassignable prop.unwrapAll().value
       prop.error message if message
 
-      prop = prop.value if prop instanceof Assign and prop.context is 'object'
+      prop = prop.value if prop instanceof Assign and
+        prop.context is 'object' and
+        prop.value?.base not instanceof Arr
       return no unless prop.isAssignable()
     yes
 
@@ -1437,15 +1489,23 @@ exports.Obj = class Obj extends Base
     return yes for prop in @properties when prop instanceof Splat
     no
 
+  # Move rest property to the end of the list.
+  # `{a, rest..., b} = obj` -> `{a, b, rest...} = obj`
+  # `foo = ({a, rest..., b}) ->` -> `foo = {a, b, rest...}) ->`
+  reorderProperties: ->
+    props = @properties
+    splatProps = (i for prop, i in props when prop instanceof Splat)
+    props[splatProps[1]].error "multiple spread elements are disallowed" if splatProps?.length > 1
+    splatProp = props.splice splatProps[0], 1
+    @objects = @properties = [].concat props, splatProp
+
   compileNode: (o) ->
+    @reorderProperties() if @hasSplat() and @lhs
     props = @properties
     if @generated
       for node in props when node instanceof Value
         node.error 'cannot have an implicit value in an implicit object'
 
-    # Object spread properties. https://github.com/tc39/proposal-object-rest-spread/blob/master/Spread.md
-    return @compileSpread o if @hasSplat() and not @csx
-
     idt      = o.indent += TAB
     lastNode = @lastNode @properties
 
@@ -1497,7 +1557,16 @@ exports.Obj = class Obj extends Base
           [key, value] = prop.base.cache o
           key  = new PropertyName key.value if key instanceof IdentifierLiteral
           prop = new Assign key, value, 'object'
-        else if not prop.bareLiteral?(IdentifierLiteral)
+        else if key instanceof Value and key.base instanceof ComputedPropertyName
+          # `{ [foo()] }` output as `{ [ref = foo()]: ref }`.
+          if prop.base.value.shouldCache()
+            [key, value] = prop.base.value.cache o
+            key  = new ComputedPropertyName key.value if key instanceof IdentifierLiteral
+            prop = new Assign key, value, 'object'
+          else
+            # `{ [expression] }` output as `{ [expression]: expression }`.
+            prop = new Assign key, prop.base.value, 'object'
+        else if not prop.bareLiteral?(IdentifierLiteral) and prop not instanceof Splat
           prop = new Assign prop, prop, 'object'
       if indent then answer.push @makeCode indent
       answer.push prop.compileToFragments(o, LEVEL_TOP)...
@@ -1516,30 +1585,6 @@ exports.Obj = class Obj extends Base
       prop = prop.unwrapAll()
       prop.eachName iterator if prop.eachName?
 
-  # Object spread properties. https://github.com/tc39/proposal-object-rest-spread/blob/master/Spread.md
-  # `obj2 = {a: 1, obj..., c: 3, d: 4}` → `obj2 = _extends({}, {a: 1}, obj, {c: 3, d: 4})`
-  compileSpread: (o) ->
-    props = @properties
-    # Store object spreads.
-    splatSlice = []
-    propSlices = []
-    slices = []
-    addSlice = ->
-      slices.push new Obj propSlices if propSlices.length
-      slices.push splatSlice... if splatSlice.length
-      splatSlice = []
-      propSlices = []
-    for prop in props
-      if prop instanceof Splat
-        splatSlice.push new Value prop.name
-        addSlice()
-      else
-        propSlices.push prop
-    addSlice()
-    slices.unshift new Obj unless slices[0] instanceof Obj
-    _extends = new Value new Literal utility '_extends', o
-    (new Call _extends, slices).compileToFragments o
-
   compileCSXAttributes: (o) ->
     props = @properties
     answer = []
@@ -1561,6 +1606,10 @@ exports.Arr = class Arr extends Base
 
   children: ['objects']
 
+  hasElision: ->
+    return yes for obj in @objects when obj instanceof Elision
+    no
+
   isAssignable: ->
     return no unless @objects.length
 
@@ -1575,6 +1624,9 @@ exports.Arr = class Arr extends Base
   compileNode: (o) ->
     return [@makeCode '[]'] unless @objects.length
     o.indent += TAB
+    fragmentIsElision = (fragment) -> fragmentsToText(fragment).trim() is ','
+    # Detect if `Elisions` at the beginning of the array are processed (e.g. [, , , a]).
+    passedElision = no
 
     answer = []
     for obj, objIndex in @objects
@@ -1590,6 +1642,7 @@ exports.Arr = class Arr extends Base
         unwrappedObj.lhs = yes if unwrappedObj instanceof Arr or unwrappedObj instanceof Obj
 
     compiledObjs = (obj.compileToFragments o, LEVEL_LIST for obj in @objects)
+    olen = compiledObjs.length
     # If `compiledObjs` includes newlines, we will output this as a multiline
     # array (i.e. with a newline and indentation after the `[`). If an element
     # contains line comments, that should also trigger multiline output since
@@ -1604,14 +1657,17 @@ exports.Arr = class Arr extends Base
           fragment.code = fragment.code.trim()
         else if index isnt 0 and includesLineCommentsOnNonFirstElement is no and hasLineComments fragment
           includesLineCommentsOnNonFirstElement = yes
-      if index isnt 0
+      # Add ', ' if all `Elisions` from the beginning of the array are processed (e.g. [, , , a]) and
+      # element isn't `Elision` or last element is `Elision` (e.g. [a,,b,,])
+      if index isnt 0 and passedElision and (not fragmentIsElision(fragments) or index is olen - 1)
         answer.push @makeCode ', '
+      passedElision = passedElision or not fragmentIsElision fragments
       answer.push fragments...
     if includesLineCommentsOnNonFirstElement or '\n' in fragmentsToText(answer)
       for fragment, fragmentIndex in answer
         if fragment.isHereComment
           fragment.code = "#{multident(fragment.code, o.indent, no)}\n#{o.indent}"
-        else if fragment.code is ', '
+        else if fragment.code is ', ' and not fragment?.isElision
           fragment.code = ",\n#{o.indent}"
       answer.unshift @makeCode "[\n#{o.indent}"
       answer.push @makeCode "\n#{@tab}]"
@@ -1843,20 +1899,20 @@ exports.ExecutableClassBody = class ExecutableClassBody extends Base
     if argumentsNode = @body.contains isLiteralArguments
       argumentsNode.error "Class bodies shouldn't reference arguments"
 
-    @name      = @class.name ? @defaultClassVariableName
-    directives = @walkBody()
-    @setContext()
-
-    ident   = new IdentifierLiteral @name
     params  = []
-    args    = []
+    args    = [new ThisLiteral]
     wrapper = new Code params, @body
-    klass   = new Parens new Call wrapper, args
+    klass   = new Parens new Call (new Value wrapper, [new Access new PropertyName 'call']), args
 
     @body.spaced = true
 
     o.classScope = wrapper.makeScope o.scope
 
+    @name      = @class.name ? o.classScope.freeVariable @defaultClassVariableName
+    ident      = new IdentifierLiteral @name
+    directives = @walkBody()
+    @setContext()
+
     if @class.hasNameClash
       parent = new IdentifierLiteral o.classScope.freeVariable 'superClass'
       wrapper.params.push new Param parent
@@ -2141,17 +2197,17 @@ exports.Assign = class Assign extends Base
         # know that, so that those nodes know that they’re assignable as
         # destructured variables.
         @variable.base.lhs = yes
-        return @compileDestructuring o unless @variable.isAssignable()
-        # Object destructuring. Can be removed once ES proposal hits Stage 4.
-        objDestructAnswer = @compileObjectDestruct(o) if @variable.isObject() and @variable.contains (node) ->
-          node instanceof Obj and node.hasSplat()
-        return objDestructAnswer if objDestructAnswer
+        unless @variable.isAssignable()
+          if @variable.isObject() and @variable.base.hasSplat()
+            return @compileObjectDestruct o
+          else
+            return @compileDestructuring o
 
       return @compileSplice       o if @variable.isSplice()
       return @compileConditional  o if @context in ['||=', '&&=', '?=']
-      return @compileSpecialMath  o if @context in ['**=', '//=', '%%=']
+      return @compileSpecialMath  o if @context in ['//=', '%%=']
 
-    unless @context
+    if not @context or @context is '**='
       varBase = @variable.unwrapAll()
       unless varBase.isAssignable()
         @variable.error "'#{@variable.compile o}' can't be assigned"
@@ -2209,97 +2265,25 @@ exports.Assign = class Assign extends Base
     answer = compiledName.concat @makeCode(" #{ @context or '=' } "), val
     # Per https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment#Assignment_without_declaration,
     # if we’re destructuring without declaring, the destructuring assignment must be wrapped in parentheses.
-    if o.level > LEVEL_LIST or o.level is LEVEL_TOP and isValue and @variable.base instanceof Obj and not @nestedLhs and not (@param is yes)
+    # The assignment is wrapped in parentheses if 'o.level' has lower precedence than LEVEL_LIST (3)
+    # (i.e. LEVEL_COND (4), LEVEL_OP (5) or LEVEL_ACCESS (6)), or if we're destructuring object, e.g. {a,b} = obj.
+    if o.level > LEVEL_LIST or isValue and @variable.base instanceof Obj and not @nestedLhs and not (@param is yes)
       @wrapInParentheses answer
     else
       answer
 
-  # Check object destructuring variable for rest elements;
-  # can be removed once ES proposal hits Stage 4.
+  # Object rest property is not assignable: `{{a}...}`
   compileObjectDestruct: (o) ->
-    # Returns a safe (cached) reference to the key for a given property
-    getPropKey = (prop) ->
-      if prop instanceof Assign
-        [prop.variable, key] = prop.variable.cache o
-        key
-      else
-        prop
-
-    # Returns the name of a given property for use with excludeProps
-    # Property names are quoted (e.g. `a: b` -> 'a'), and everything else uses the key reference
-    # (e.g. `'a': b -> 'a'`, `"#{a}": b` -> <cached>`)
-    getPropName = (prop) ->
-      key = getPropKey prop
-      cached = prop instanceof Assign and prop.variable isnt key
-      if cached or not key.isAssignable()
-        key
-      else
-        new Literal "'#{key.compileWithoutComments o}'"
-
-    # Recursive function for searching and storing rest elements in objects.
-    # e.g. `{[properties...]} = source`.
-    traverseRest = (properties, source) =>
-      restElements = []
-      restIndex = undefined
-      source = new Value source unless source.properties?
-
-      for prop, index in properties
-        nestedSourceDefault = nestedSource = nestedProperties = null
-        if prop instanceof Assign
-          # prop is `k: expr`, we need to check `expr` for nested splats
-          if prop.value.isObject?()
-            # prop is `k = {...} `
-            continue unless prop.context is 'object'
-            # prop is `k: {...}`
-            nestedProperties = prop.value.base.properties
-          else if prop.value instanceof Assign and prop.value.variable.isObject()
-            # prop is `k: {...} = default`
-            nestedProperties = prop.value.variable.base.properties
-            [prop.value.value, nestedSourceDefault] = prop.value.value.cache o
-          if nestedProperties
-            nestedSource = new Value source.base, source.properties.concat [new Access getPropKey prop]
-            nestedSource = new Value new Op '?', nestedSource, nestedSourceDefault if nestedSourceDefault
-            restElements.push traverseRest(nestedProperties, nestedSource)...
-        else if prop instanceof Splat
-          prop.error "multiple rest elements are disallowed in object destructuring" if restIndex?
-          restIndex = index
-          restElements.push {
-            name: prop.name.unwrapAll()
-            source
-            excludeProps: new Arr (getPropName p for p in properties when p isnt prop)
-          }
-
-      if restIndex?
-        # Remove rest element from the properties after iteration
-        properties.splice restIndex, 1
-
-      restElements
-
-    # Cache the value for reuse with rest elements.
-    valueRefTemp =
-      if @value.shouldCache()
-        new IdentifierLiteral o.scope.freeVariable 'ref', reserve: false
-      else
-        @value.base
-
-    # Find all rest elements.
-    restElements = traverseRest @variable.base.properties, valueRefTemp
-    return no unless restElements and restElements.length > 0
-
-    [@value, valueRef] = @value.cache o
-    result = new Block [@]
-
-    for restElement in restElements
-      value = new Call new Value(new Literal utility 'objectWithoutKeys', o), [restElement.source, restElement.excludeProps]
-      result.push new Assign new Value(restElement.name), value, null, param: if @param then 'alwaysDeclare' else null
-
-    fragments = result.compileToFragments o
-    if o.level is LEVEL_TOP
-      # Remove leading tab and trailing semicolon
-      fragments.shift()
-      fragments.pop()
-
-    fragments
+    @variable.base.reorderProperties()
+    {properties: props} = @variable.base
+    [..., splat] = props
+    splatProp = splat.name
+    assigns = []
+    refVal = new Value new IdentifierLiteral o.scope.freeVariable 'ref'
+    props.splice -1, 1, new Splat refVal
+    assigns.push new Assign(new Value(new Obj props), @value).compileToFragments o, LEVEL_LIST
+    assigns.push new Assign(new Value(splatProp), refVal).compileToFragments o, LEVEL_LIST
+    @joinFragmentArrays assigns, ', '
 
   # Brief implementation of recursive pattern matching, when assigning array or
   # object literals to a value. Peeks at their properties to assign inner names.
@@ -2320,47 +2304,33 @@ exports.Assign = class Assign extends Base
     if olen is 1 and obj instanceof Expansion
       obj.error 'Destructuring assignment has no target'
 
-    isObject = @variable.isObject()
+    # Count all `Splats`: [a, b, c..., d, e]
+    splats = (i for obj, i in objects when obj instanceof Splat)
+    # Count all `Expansions`: [a, b, ..., c, d]
+    expans = (i for obj, i in objects when obj instanceof Expansion)
+    # Combine splats and expansions.
+    splatsAndExpans = [splats..., expans...]
+    # Show error if there is more than one `Splat`, or `Expansion`.
+    # Examples: [a, b, c..., d, e, f...], [a, b, ..., c, d, ...], [a, b, ..., c, d, e...]
+    if splatsAndExpans.length > 1
+      # Sort 'splatsAndExpans' so we can show error at first disallowed token.
+      objects[splatsAndExpans.sort()[1]].error "multiple splats/expansions are disallowed in an assignment"
 
-    # Special case for when there's only one thing destructured off of
-    # something. `{a} = b`, `[a] = b`, `{a: b} = c`
-    if top and olen is 1 and obj not instanceof Splat
-      # Pick the property straight off the value when there’s just one to pick
-      # (no need to cache the value into a variable).
-      defaultValue = undefined
-      if obj instanceof Assign and obj.context is 'object'
-        # A regular object pattern-match.
-        {variable: {base: idx}, value: obj} = obj
-        if obj instanceof Assign
-          defaultValue = obj.value
-          obj = obj.variable
-      else
-        if obj instanceof Assign
-          defaultValue = obj.value
-          obj = obj.variable
-        idx = if isObject
-          # A shorthand `{a, b, @c} = val` pattern-match.
-          if obj.this
-            obj.properties[0].name
-          else
-            new PropertyName obj.unwrap().value
-        else
-          # A regular array pattern-match.
-          new NumberLiteral 0
-      acc   = idx.unwrap() instanceof PropertyName
-      value = new Value value
-      value.properties.push new (if acc then Access else Index) idx
-      message = isUnassignable obj.unwrap().value
-      obj.error message if message
-      if defaultValue
-        defaultValue.isDefaultValue = yes
-        value = new Op '?', value, defaultValue
-      return new Assign(obj, value, null, param: @param).compileToFragments o, LEVEL_TOP
+    isSplat = splats?.length > 0
+    isExpans = expans?.length > 0
 
     vvar     = value.compileToFragments o, LEVEL_LIST
     vvarText = fragmentsToText vvar
     assigns  = []
-    expandedIdx = false
+    pushAssign = (variable, val) =>
+      assigns.push new Assign(variable, val, null, param: @param, subpattern: yes).compileToFragments o, LEVEL_LIST
+
+    if isSplat
+      splatVar = objects[splats[0]].name.unwrap()
+      if splatVar instanceof Arr or splatVar instanceof Obj
+        splatVarRef = new IdentifierLiteral o.scope.freeVariable 'ref'
+        objects[splats[0]].name = splatVarRef
+        splatVarAssign = -> pushAssign new Value(splatVar), splatVarRef
 
     # At this point, there are several things to destructure. So the `fn()` in
     # `{a, b} = fn()` must be cached, for example. Make vvar into a simple
@@ -2371,75 +2341,104 @@ exports.Assign = class Assign extends Base
       vvar = [@makeCode ref]
       vvarText = ref
 
-    # And here comes the big loop that handles all of these cases:
-    # `[a, b] = c`
-    # `[a..., b] = c`
-    # `[..., a, b] = c`
-    # `[@a, b] = c`
-    # `[a = 1, b] = c`
-    # `{a, b} = c`
-    # `{@a, b} = c`
-    # `{a = 1, b} = c`
-    # etc.
-    for obj, i in objects
-      idx = i
-      if not expandedIdx and obj instanceof Splat
-        name = obj.name.unwrap().value
-        obj = obj.unwrap()
-        val = "#{olen} <= #{vvarText}.length ? #{utility 'slice', o}.call(#{vvarText}, #{i}"
-        rest = olen - i - 1
-        if rest isnt 0
-          ivar = o.scope.freeVariable 'i', single: true
-          val += ", #{ivar} = #{vvarText}.length - #{rest}) : (#{ivar} = #{i}, [])"
-        else
-          val += ") : []"
-        val   = new Literal val
-        expandedIdx = "#{ivar}++"
-      else if not expandedIdx and obj instanceof Expansion
-        rest = olen - i - 1
-        if rest isnt 0
-          if rest is 1
-            expandedIdx = "#{vvarText}.length - 1"
-          else
-            ivar = o.scope.freeVariable 'i', single: true
-            val = new Literal "#{ivar} = #{vvarText}.length - #{rest}"
-            expandedIdx = "#{ivar}++"
-            assigns.push val.compileToFragments o, LEVEL_LIST
-        continue
-      else
-        if obj instanceof Splat or obj instanceof Expansion
-          obj.error "multiple splats/expansions are disallowed in an assignment"
-        defaultValue = undefined
-        if obj instanceof Assign and obj.context is 'object'
-          # A regular object pattern-match.
-          {variable: {base: idx}, value: obj} = obj
-          if obj instanceof Assign
-            defaultValue = obj.value
-            obj = obj.variable
-        else
-          if obj instanceof Assign
-            defaultValue = obj.value
-            obj = obj.variable
-          idx = if isObject
-            # A shorthand `{a, b, @c} = val` pattern-match.
-            if obj.this
-              obj.properties[0].name
-            else
-              new PropertyName obj.unwrap().value
-          else
-            # A regular array pattern-match.
-            new Literal expandedIdx or idx
-        name = obj.unwrap().value
-        acc = idx.unwrap() instanceof PropertyName
-        val = new Value new Literal(vvarText), [new (if acc then Access else Index) idx]
-        if defaultValue
-          defaultValue.isDefaultValue = yes
-          val = new Op '?', val, defaultValue
-      if name?
-        message = isUnassignable name
-        obj.error message if message
-      assigns.push new Assign(obj, val, null, param: @param, subpattern: yes).compileToFragments o, LEVEL_LIST
+    slicer = (type) -> (vvar, start, end = no) ->
+      vvar = new IdentifierLiteral vvar unless vvar instanceof Value
+      args = [vvar, new NumberLiteral(start)]
+      args.push new NumberLiteral end if end
+      slice = new Value (new IdentifierLiteral utility type, o), [new Access new PropertyName 'call']
+      new Value new Call slice, args
 
+    # Helper which outputs `[].slice` code.
+    compSlice = slicer "slice"
+
+    # Helper which outputs `[].splice` code.
+    compSplice = slicer "splice"
+
+    # Check if `objects` array contains any instance of `Assign`, e.g. {a:1}.
+    hasObjAssigns = (objs) ->
+      (i for obj, i in objs when obj instanceof Assign and obj.context is 'object')
+
+    # Check if `objects` array contains any unassignable object.
+    objIsUnassignable = (objs) ->
+      return yes for obj in objs when not obj.isAssignable()
+      no
+
+    # `objects` are complex when there is object assign ({a:1}),
+    # unassignable object, or just a single node.
+    complexObjects = (objs) ->
+      hasObjAssigns(objs).length or objIsUnassignable(objs) or olen is 1
+
+    # "Complex" `objects` are processed in a loop.
+    # Examples: [a, b, {c, r...}, d], [a, ..., {b, r...}, c, d]
+    loopObjects = (objs, vvar, vvarTxt) =>
+      for obj, i in objs
+        # `Elision` can be skipped.
+        continue if obj instanceof Elision
+        # If `obj` is {a: 1}
+        if obj instanceof Assign and obj.context is 'object'
+          {variable: {base: idx}, value: vvar} = obj
+          {variable: vvar} = vvar if vvar instanceof Assign
+          idx =
+            if vvar.this
+              vvar.properties[0].name
+            else
+              new PropertyName vvar.unwrap().value
+          acc = idx.unwrap() instanceof PropertyName
+          vval = new Value value, [new (if acc then Access else Index) idx]
+        else
+          # `obj` is [a...], {a...} or a
+          vvar = switch
+            when obj instanceof Splat then new Value obj.name
+            else obj
+          vval = switch
+            when obj instanceof Splat then compSlice(vvarTxt, i)
+            else new Value new Literal(vvarTxt), [new Index new NumberLiteral i]
+        message = isUnassignable vvar.unwrap().value
+        vvar.error message if message
+        pushAssign vvar, vval
+
+    # "Simple" `objects` can be split and compiled to arrays, [a, b, c] = arr, [a, b, c...] = arr
+    assignObjects = (objs, vvar, vvarTxt) =>
+      vvar = new Value new Arr(objs, yes)
+      vval = if vvarTxt instanceof Value then vvarTxt else new Value new Literal(vvarTxt)
+      pushAssign vvar, vval
+
+    processObjects = (objs, vvar, vvarTxt) ->
+      if complexObjects objs
+        loopObjects objs, vvar, vvarTxt
+      else
+        assignObjects objs, vvar, vvarTxt
+
+    # In case there is `Splat` or `Expansion` in `objects`,
+    # we can split array in two simple subarrays.
+    # `Splat` [a, b, c..., d, e] can be split into  [a, b, c...] and [d, e].
+    # `Expansion` [a, b, ..., c, d] can be split into [a, b] and [c, d].
+    # Examples:
+    # a) `Splat`
+    #   CS: [a, b, c..., d, e] = arr
+    #   JS: [a, b, ...c] = arr, [d, e] = splice.call(c, -2)
+    # b) `Expansion`
+    #   CS: [a, b, ..., d, e] = arr
+    #   JS: [a, b] = arr, [d, e] = slice.call(arr, -2)
+    if splatsAndExpans.length
+      expIdx = splatsAndExpans[0]
+      leftObjs = objects.slice 0, expIdx + (if isSplat then 1 else 0)
+      rightObjs = objects.slice expIdx + 1
+      processObjects leftObjs, vvar, vvarText if leftObjs.length isnt 0
+      if rightObjs.length isnt 0
+        # Slice or splice `objects`.
+        refExp = switch
+          when isSplat then compSplice new Value(objects[expIdx].name), rightObjs.length * -1
+          when isExpans then compSlice vvarText, rightObjs.length * -1
+        if complexObjects rightObjs
+          restVar = refExp
+          refExp = o.scope.freeVariable 'ref'
+          assigns.push [@makeCode(refExp + ' = '), restVar.compileToFragments(o, LEVEL_LIST)...]
+        processObjects rightObjs, vvar, refExp
+    else
+      # There is no `Splat` or `Expansion` in `objects`.
+      processObjects objects, vvar, vvarText
+    splatVarAssign?()
     assigns.push vvar unless top or @subpattern
     fragments = @joinFragmentArrays assigns, ', '
     if o.level < LEVEL_LIST then fragments else @wrapInParentheses fragments
@@ -2460,7 +2459,7 @@ exports.Assign = class Assign extends Base
       fragments = new Op(@context[...-1], left, new Assign(right, @value, '=')).compileToFragments o
       if o.level <= LEVEL_LIST then fragments else @wrapInParentheses fragments
 
-  # Convert special math assignment operators like `a **= b` to the equivalent
+  # Convert special math assignment operators like `a //= b` to the equivalent
   # extended form `a = a ** b` and then compiles that.
   compileSpecialMath: (o) ->
     [left, right] = @variable.cacheReference o
@@ -2522,8 +2521,8 @@ exports.Code = class Code extends Base
         @isGenerator = yes
       if (node instanceof Op and node.isAwait()) or node instanceof AwaitReturn
         @isAsync = yes
-      if @isGenerator and @isAsync
-        node.error "function can't contain both yield and await"
+      if node instanceof For and node.isAwait()
+        @isAsync = yes
 
   children: ['params', 'body']
 
@@ -2562,14 +2561,24 @@ exports.Code = class Code extends Base
 
     # Check for duplicate parameters and separate `this` assignments.
     paramNames = []
-    @eachParamName (name, node, param) ->
+    @eachParamName (name, node, param, obj) ->
       node.error "multiple parameters named '#{name}'" if name in paramNames
       paramNames.push name
+
       if node.this
         name   = node.properties[0].name.value
         name   = "_#{name}" if name in JS_FORBIDDEN
-        target = new IdentifierLiteral o.scope.freeVariable name
-        param.renameParam node, target
+        target = new IdentifierLiteral o.scope.freeVariable name, reserve: no
+        # `Param` is object destructuring with a default value: ({@prop = 1}) ->
+        # In a case when the variable name is already reserved, we have to assign
+        # a new variable name to the destructured variable: ({prop:prop1 = 1}) ->
+        replacement =
+            if param.name instanceof Obj and obj instanceof Assign and
+                obj.operatorToken.value is '='
+              new Assign (new IdentifierLiteral name), target, 'object' #, operatorToken: new Literal ':'
+            else
+              target
+        param.renameParam node, replacement
         thisAssignments.push new Assign node, target
 
     # Parse the parameters, adding them to the list of parameters to put in the
@@ -2591,7 +2600,7 @@ exports.Code = class Code extends Base
           param.error 'an expansion parameter cannot be the only parameter in a function definition'
         haveSplatParam = yes
         if param.splat
-          if param.name instanceof Arr
+          if param.name instanceof Arr or param.name instanceof Obj
             # Splat arrays are treated oddly by ES; deal with them the legacy
             # way in the function body. TODO: Should this be handled in the
             # function parameter list, and if so, how?
@@ -2645,17 +2654,7 @@ exports.Code = class Code extends Base
           if param.name instanceof Arr or param.name instanceof Obj
             # This parameter is destructured.
             param.name.lhs = yes
-            # Compile `foo({a, b...}) ->` to `foo(arg) -> {a, b...} = arg`.
-            # Can be removed once ES proposal hits Stage 4.
-            if param.name instanceof Obj and param.name.hasSplat()
-              splatParamName = o.scope.freeVariable 'arg'
-              o.scope.parameter splatParamName
-              ref = new Value new IdentifierLiteral splatParamName
-              exprs.push new Assign new Value(param.name), ref, null, param: 'alwaysDeclare'
-              # Compile `foo({a, b...} = {}) ->` to `foo(arg = {}) -> {a, b...} = arg`.
-              if param.value? and not param.assignedInBody
-                ref = new Assign ref, param.value, null, param: yes
-            else unless param.shouldCache()
+            unless param.shouldCache()
               param.name.eachName (prop) ->
                 o.scope.parameter prop.value
           else
@@ -2697,6 +2696,12 @@ exports.Code = class Code extends Base
       @body.expressions.unshift new Call(boundMethodCheck, [new Value(new ThisLiteral), @classVariable])
     @body.makeReturn() unless wasEmpty or @noReturn
 
+    # JavaScript doesn’t allow bound (`=>`) functions to also be generators.
+    # This is usually caught via `Op::compileContinuation`, but double-check:
+    if @bound and @isGenerator
+      yieldNode = @body.contains (node) -> node instanceof Op and node.operator is 'yield'
+      (yieldNode or @).error 'yield cannot occur inside bound (fat arrow) functions'
+
     # Assemble the output
     modifiers = []
     modifiers.push 'static' if @isMethod and @isStatic
@@ -2794,7 +2799,9 @@ exports.Code = class Code extends Base
         # cannot be given an argument with a reference to `this`, as that would
         # be referencing `this` before calling `super`.
         unless child.variable.accessor
-          Block.wrap(child.args).traverseChildren yes, (node) =>
+          childArgs = child.args.filter (arg) ->
+            arg not instanceof Class and (arg not instanceof Code or arg.bound)
+          Block.wrap(childArgs).traverseChildren yes, (node) =>
             node.error "Can't call super with @params in derived class constructors" if node.this
         seenSuper = yes
         iterator child
@@ -2852,12 +2859,14 @@ exports.Param = class Param extends Base
   # `name` is the name of the parameter and `node` is the AST node corresponding
   # to that name.
   eachName: (iterator, name = @name) ->
-    atParam = (obj) => iterator "@#{obj.properties[0].name.value}", obj, @
+    atParam = (obj, originalObj = null) => iterator "@#{obj.properties[0].name.value}", obj, @, originalObj
     # * simple literals `foo`
     return iterator name.value, name, @ if name instanceof Literal
     # * at-params `@foo`
     return atParam name if name instanceof Value
     for obj in name.objects ? []
+      # Save original obj.
+      nObj = obj
       # * destructured parameter with default value
       if obj instanceof Assign and not obj.context?
         obj = obj.variable
@@ -2879,9 +2888,11 @@ exports.Param = class Param extends Base
           @eachName iterator, obj.base
         # * at-params within destructured parameters `{@foo}`
         else if obj.this
-          atParam obj
+          atParam obj, nObj
         # * simple destructured parameters {foo}
         else iterator obj.base.value, obj.base, @
+      else if obj instanceof Elision
+        obj
       else if obj not instanceof Expansion
         obj.error "illegal parameter #{obj.compile()}"
     return
@@ -2894,7 +2905,14 @@ exports.Param = class Param extends Base
       if parent instanceof Obj
         key = node
         key = node.properties[0].name if node.this
-        new Assign new Value(key), newNode, 'object'
+        # No need to assign a new variable for the destructured variable if the variable isn't reserved.
+        # Examples:
+        # `({@foo}) ->`  should compile to `({foo}) { this.foo = foo}`
+        # `foo = 1; ({@foo}) ->` should compile to `foo = 1; ({foo:foo1}) { this.foo = foo1 }`
+        if node.this and key.value is newNode.value
+          new Value newNode
+        else
+          new Assign new Value(key), newNode, 'object'
       else
         newNode
 
@@ -2911,7 +2929,10 @@ exports.Splat = class Splat extends Base
 
   children: ['name']
 
+  shouldCache: -> no
+
   isAssignable: ->
+    return no if @name instanceof Obj or @name instanceof Parens
     @name.isAssignable() and (not @name.isAtomic or @name.isAtomic())
 
   assigns: (name) ->
@@ -2938,6 +2959,28 @@ exports.Expansion = class Expansion extends Base
 
   eachName: (iterator) ->
 
+#### Elision
+
+# Array elision element (for example, [,a, , , b, , c, ,]).
+exports.Elision = class Elision extends Base
+
+  isAssignable: YES
+
+  shouldCache: NO
+
+  compileToFragments: (o, level) ->
+    fragment = super o, level
+    fragment.isElision = yes
+    fragment
+
+  compileNode: (o) ->
+    [@makeCode ', ']
+
+  asReference: (o) ->
+    this
+
+  eachName: (iterator) ->
+
 #### While
 
 # A while loop, the only sort of low-level loop exposed by CoffeeScript. From
@@ -3114,7 +3157,6 @@ exports.Op = class Op extends Base
     return @compileChain        o if isChain
     switch @operator
       when '?'  then @compileExistence o, @second.isDefaultValue
-      when '**' then @compilePower o
       when '//' then @compileFloorDivision o
       when '%%' then @compileModulo o
       else
@@ -3181,11 +3223,6 @@ exports.Op = class Op extends Base
       parts.push [@makeCode ")"] if o.level >= LEVEL_PAREN
     @joinFragmentArrays parts, ''
 
-  compilePower: (o) ->
-    # Make a Math.pow call
-    pow = new Value new IdentifierLiteral('Math'), [new Access new PropertyName 'pow']
-    new Call(pow, [@first, @second]).compileToFragments o
-
   compileFloorDivision: (o) ->
     floor = new Value new IdentifierLiteral('Math'), [new Access new PropertyName 'floor']
     second = if @second.shouldCache() then new Parens @second else @second
@@ -3482,15 +3519,27 @@ exports.StringWithInterpolations = class StringWithInterpolations extends Base
 exports.For = class For extends While
   constructor: (body, source) ->
     super()
-    {@source, @guard, @step, @name, @index} = source
-    @body    = Block.wrap [body]
-    @own     = source.own?
-    @object  = source.object?
-    @from    = source.from?
+    @addBody body
+    @addSource source
+
+  children: ['body', 'source', 'guard', 'step']
+
+  isAwait: -> @await ? no
+
+  addBody: (body) ->
+    @body = Block.wrap [body]
+    this
+
+  addSource: (source) ->
+    {@source  = no} = source
+    attribs   = ["name", "index", "guard", "step", "own", "ownTag", "await", "awaitTag", "object", "from"]
+    @[attr]   = source[attr] ? @[attr] for attr in attribs
+    return this unless @source
     @index.error 'cannot use index with for-from' if @from and @index
-    source.ownTag.error "cannot use own with for-#{if @from then 'from' else 'in'}" if @own and not @object
+    @ownTag.error "cannot use own with for-#{if @from then 'from' else 'in'}" if @own and not @object
     [@name, @index] = [@index, @name] if @object
     @index.error 'index cannot be a pattern matching expression' if @index?.isArray?() or @index?.isObject?()
+    @awaitTag.error 'await must be used with for-from' if @await and not @from
     @range   = @source instanceof Value and @source.base instanceof Range and not @source.properties.length and not @from
     @pattern = @name instanceof Value
     @index.error 'indexes do not apply to range loops' if @range and @index
@@ -3509,8 +3558,7 @@ exports.For = class For extends While
           comment.newLine = comment.unshift = yes for comment in node.comments
           moveComments node, @[attribute]
       moveComments @[attribute], @
-
-  children: ['body', 'source', 'guard', 'step']
+    this
 
   # Welcome to the hairiest method in all of CoffeeScript. Handles the inner
   # loop, filtering, stepping, and result saving for array, object, and range
@@ -3582,47 +3630,31 @@ exports.For = class For extends While
         body = Block.wrap [new If @guard, body] if @guard
     if @pattern
       body.expressions.unshift new Assign @name, if @from then new IdentifierLiteral kvar else new Literal "#{svar}[#{kvar}]"
-    defPartFragments = [].concat @makeCode(defPart), @pluckDirectCall(o, body)
+
     varPart = "\n#{idt1}#{namePart};" if namePart
     if @object
       forPartFragments = [@makeCode("#{kvar} in #{svar}")]
       guardPart = "\n#{idt1}if (!#{utility 'hasProp', o}.call(#{svar}, #{kvar})) continue;" if @own
     else if @from
-      forPartFragments = [@makeCode("#{kvar} of #{svar}")]
+      if @await
+        forPartFragments = new Op 'await', new Parens new Literal "#{kvar} of #{svar}"
+        forPartFragments = forPartFragments.compileToFragments o, LEVEL_TOP
+      else
+        forPartFragments = [@makeCode("#{kvar} of #{svar}")]
     bodyFragments = body.compileToFragments merge(o, indent: idt1), LEVEL_TOP
     if bodyFragments and bodyFragments.length > 0
       bodyFragments = [].concat @makeCode('\n'), bodyFragments, @makeCode('\n')
 
-    fragments = []
-    if defPartFragments? and fragmentsToText(defPartFragments) isnt ''
-      fragments = fragments.concat defPartFragments
+    fragments = [@makeCode(defPart)]
     fragments.push @makeCode(resultPart) if resultPart
-    fragments = fragments.concat @makeCode(@tab), @makeCode( 'for ('),
-      forPartFragments, @makeCode(") {#{guardPart}#{varPart}"), bodyFragments,
+    forCode = if @await then 'for ' else 'for ('
+    forClose = if @await then '' else ')'
+    fragments = fragments.concat @makeCode(@tab), @makeCode( forCode),
+      forPartFragments, @makeCode("#{forClose} {#{guardPart}#{varPart}"), bodyFragments,
       @makeCode(@tab), @makeCode('}')
     fragments.push @makeCode(returnResult) if returnResult
     fragments
 
-  pluckDirectCall: (o, body) ->
-    defs = []
-    for expr, idx in body.expressions
-      expr = expr.unwrapAll()
-      continue unless expr instanceof Call
-      val = expr.variable?.unwrapAll()
-      continue unless (val instanceof Code) or
-                      (val instanceof Value and
-                      val.base?.unwrapAll() instanceof Code and
-                      val.properties.length is 1 and
-                      val.properties[0].name?.value in ['call', 'apply'])
-      fn    = val.base?.unwrapAll() or val
-      ref   = new IdentifierLiteral o.scope.freeVariable 'fn'
-      base  = new Value ref
-      if val.base
-        [val.base, base] = [base, val]
-      body.expressions[idx] = new Call base, expr.args
-      defs = defs.concat @makeCode(@tab), (new Assign(ref, fn).compileToFragments(o, LEVEL_TOP)), @makeCode(';\n')
-    defs
-
 #### Switch
 
 # A JavaScript *switch* statement. Converts into a returnable expression on-demand.
@@ -3755,13 +3787,7 @@ exports.If = class If extends Base
 
 UTILITIES =
   modulo: -> 'function(a, b) { return (+a % (b = +b) + b) % b; }'
-  objectWithoutKeys: -> "
-      function(o, ks) {
-        var res = {};
-        for (var k in o) ([].indexOf.call(ks, k) < 0 && {}.hasOwnProperty.call(o, k)) && (res[k] = o[k]);
-        return res;
-      }
-    "
+
   boundMethodCheck: -> "
     function(instance, Constructor) {
       if (!(instance instanceof Constructor)) {
@@ -3769,19 +3795,6 @@ UTILITIES =
       }
     }
   "
-  _extends: -> "
-    Object.assign || function (target) {
-      for (var i = 1; i < arguments.length; i++) {
-        var source = arguments[i];
-        for (var key in source) {
-          if (Object.prototype.hasOwnProperty.call(source, key)) {
-            target[key] = source[key];
-          }
-        }
-      }
-      return target;
-    }
-  "
 
   # Shortcuts to speed up the lookup time for native functions.
   hasProp: -> '{}.hasOwnProperty'

src/repl.coffee

@@ -30,6 +30,14 @@ replDefaults =
     try
       # Tokenize the clean input.
       tokens = CoffeeScript.tokens input
+      # Filter out tokens generated just to hold comments.
+      if tokens.length >= 2 and tokens[0].generated and
+         tokens[0].comments?.length isnt 0 and tokens[0][1] is '' and
+         tokens[1][0] is 'TERMINATOR'
+        tokens = tokens[2...]
+      if tokens.length >= 1 and tokens[tokens.length - 1].generated and
+         tokens[tokens.length - 1].comments?.length isnt 0 and tokens[tokens.length - 1][1] is ''
+        tokens.pop()
       # Collect referenced variable names just like in `CoffeeScript.compile`.
       referencedVars = (token[1] for token in tokens when token[0] is 'IDENTIFIER')
       # Generate the AST of the tokens.

src/rewriter.coffee

@@ -263,6 +263,20 @@ exports.Rewriter = class Rewriter
             stack.pop()
         start = stack.pop()
 
+      inControlFlow = =>
+        seenFor = @findTagsBackwards(i, ['FOR']) and @findTagsBackwards(i, ['FORIN', 'FOROF', 'FORFROM'])
+        controlFlow = seenFor or @findTagsBackwards i, ['WHILE', 'UNTIL', 'LOOP', 'LEADING_WHEN']
+        return no unless controlFlow
+        isFunc = no
+        tagCurrentLine = token[2].first_line
+        @detectEnd i,
+          (token, i) -> token[0] in LINEBREAKS
+          (token, i) ->
+            [prevTag, ,{first_line}] = tokens[i - 1] || []
+            isFunc = tagCurrentLine is first_line and prevTag in ['->', '=>']
+          returnOnNegativeLevel: yes
+        isFunc
+
       # Recognize standard implicit calls like
       # f a, f() b, f? c, h[0] d etc.
       # Added support for spread dots on the left side: f ...a
@@ -271,7 +285,8 @@ exports.Rewriter = class Rewriter
          (nextTag in IMPLICIT_CALL or
          (nextTag is '...' and @tag(i + 2) in IMPLICIT_CALL and not @findTagsBackwards(i, ['INDEX_START', '['])) or
           nextTag in IMPLICIT_UNSPACED_CALL and
-          not nextToken.spaced and not nextToken.newLine)
+          not nextToken.spaced and not nextToken.newLine) and
+          not inControlFlow()
         tag = token[0] = 'FUNC_EXIST' if tag is '?'
         startImplicitCall i + 1
         return forward(2)
@@ -343,11 +358,14 @@ exports.Rewriter = class Rewriter
           stackItem[2].sameLine = no if isImplicitObject stackItem
 
       newLine = prevTag is 'OUTDENT' or prevToken.newLine
-      if tag in IMPLICIT_END or tag in CALL_CLOSERS and newLine
+      if tag in IMPLICIT_END or
+          (tag in CALL_CLOSERS and newLine) or
+          (tag in ['..', '...'] and @findTagsBackwards(i, ["INDEX_START"]))
         while inImplicit()
           [stackTag, stackIdx, {sameLine, startsLine}] = stackTop()
           # Close implicit calls when reached end of argument list
-          if inImplicitCall() and prevTag isnt ','
+          if inImplicitCall() and prevTag isnt ',' or
+              (prevTag is ',' and tag is 'TERMINATOR' and not nextTag?)
             endImplicitCall()
           # Close implicit objects such as:
           # return a: 1, b: 2 unless true
@@ -377,7 +395,7 @@ exports.Rewriter = class Rewriter
       #
       #     f a, b: c, d: e, f, g: h: i, j
       #
-      if tag is ',' and not @looksObjectish(i + 1) and inImplicitObject() and
+      if tag is ',' and not @looksObjectish(i + 1) and inImplicitObject() and not (@tag(i + 2) in ['FOROF', 'FORIN']) and
          (nextTag isnt 'TERMINATOR' or not @looksObjectish(i + 2))
         # When nextTag is OUTDENT the comma is insignificant and
         # should just be ignored so embed it in the implicit object.
@@ -544,20 +562,49 @@ exports.Rewriter = class Rewriter
   # blocks are added.
   normalizeLines: ->
     starter = indent = outdent = null
+    leading_switch_when = null
+    leading_if_then = null
+    # Count `THEN` tags
+    ifThens = []
 
     condition = (token, i) ->
       token[1] isnt ';' and token[0] in SINGLE_CLOSERS and
       not (token[0] is 'TERMINATOR' and @tag(i + 1) in EXPRESSION_CLOSE) and
-      not (token[0] is 'ELSE' and starter isnt 'THEN') and
+      not (token[0] is 'ELSE' and
+           (starter isnt 'THEN' or (leading_if_then or leading_switch_when))) and
       not (token[0] in ['CATCH', 'FINALLY'] and starter in ['->', '=>']) or
       token[0] in CALL_CLOSERS and
       (@tokens[i - 1].newLine or @tokens[i - 1][0] is 'OUTDENT')
 
     action = (token, i) ->
+      ifThens.pop() if token[0] is 'ELSE' and starter is 'THEN'
       @tokens.splice (if @tag(i - 1) is ',' then i - 1 else i), 0, outdent
 
+    closeElseTag = (tokens, i) =>
+      tlen = ifThens.length
+      return i unless tlen > 0
+      lastThen = ifThens.pop()
+      [, outdentElse] = @indentation tokens[lastThen]
+      # Insert `OUTDENT` to close inner `IF`.
+      outdentElse[1] = tlen*2
+      tokens.splice(i, 0, outdentElse)
+      # Insert `OUTDENT` to close outer `IF`.
+      outdentElse[1] = 2
+      tokens.splice(i + 1, 0, outdentElse)
+      # Remove outdents from the end.
+      @detectEnd i + 2,
+        (token, i) -> token[0] in ['OUTDENT', 'TERMINATOR']
+        (token, i) ->
+            if @tag(i) is 'OUTDENT' and @tag(i + 1) is 'OUTDENT'
+              tokens.splice i, 2
+      i + 2
+
     @scanTokens (token, i, tokens) ->
       [tag] = token
+      conditionTag = tag in ['->', '=>'] and
+        @findTagsBackwards(i, ['IF', 'WHILE', 'FOR', 'UNTIL', 'SWITCH', 'WHEN', 'LEADING_WHEN', '[', 'INDEX_START']) and
+        not (@findTagsBackwards i, ['THEN', '..', '...'])
+
       if tag is 'TERMINATOR'
         if @tag(i + 1) is 'ELSE' and @tag(i - 1) isnt 'OUTDENT'
           tokens.splice i, 1, @indentation()...
@@ -574,10 +621,18 @@ exports.Rewriter = class Rewriter
         tokens.splice i + 1, 0, indent, outdent
         return 1
       if tag in SINGLE_LINERS and @tag(i + 1) isnt 'INDENT' and
-         not (tag is 'ELSE' and @tag(i + 1) is 'IF')
+         not (tag is 'ELSE' and @tag(i + 1) is 'IF') and
+         not conditionTag
         starter = tag
         [indent, outdent] = @indentation tokens[i]
         indent.fromThen   = true if starter is 'THEN'
+        if tag is 'THEN'
+          leading_switch_when = @findTagsBackwards(i, ['LEADING_WHEN']) and @tag(i + 1) is 'IF'
+          leading_if_then = @findTagsBackwards(i, ['IF']) and @tag(i + 1) is 'IF'
+        ifThens.push i if tag is 'THEN' and @findTagsBackwards(i, ['IF'])
+        # `ELSE` tag is not closed.
+        if tag is 'ELSE' and @tag(i - 1) isnt 'OUTDENT'
+          i = closeElseTag tokens, i
         tokens.splice i + 1, 0, indent
         @detectEnd i + 2, condition, action
         tokens.splice i, 1 if tag is 'THEN'

test/arrays.coffee

@@ -26,6 +26,94 @@ test "incorrect indentation without commas", ->
   ok result[0][0] is 'a'
   ok result[1]['b'] is 'c'
 
+# Elisions
+test "array elisions", ->
+  eq [,1].length, 2
+  eq [,,1,2,,].length, 5
+  arr = [1,,2]
+  eq arr.length, 3
+  eq arr[1], undefined
+  eq [,,].length, 2
+
+test "array elisions indentation and commas", ->
+  arr1 = [
+    , 1, 2, , , 3,
+    4, 5, 6
+    , , 8, 9,
+  ]
+  eq arr1.length, 12
+  eq arr1[5], 3
+  eq arr1[9], undefined
+  arr2 = [, , 1,
+    2, , 3,
+    , 4, 5
+    6
+    , , ,
+  ]
+  eq arr2.length, 12
+  eq arr2[8], 5
+  eq arr2[1], undefined
+
+test "array elisions destructuring", ->
+  arr = [1,2,3,4,5,6,7,8,9]
+  [,a] = arr
+  [,,,b] = arr
+  arrayEq [a,b], [2,4]
+  [,a,,b,,c,,,d] = arr
+  arrayEq [a,b,c,d], [2,4,6,9]
+  [
+    ,e,
+    ,f,
+    ,g,
+    ,,h] = arr
+  arrayEq [e,f,g,h], [2,4,6,9]
+
+test "array elisions destructuring with splats and expansions", ->
+  arr = [1,2,3,4,5,6,7,8,9]
+  [,a,,,b...] = arr
+  arrayEq [a,b], [2,[5,6,7,8,9]]
+  [,c,...,,d,,e] = arr
+  arrayEq [c,d,e], [2,7,9]
+  [...,f,,,g,,,] = arr
+  arrayEq [f,g], [4,7]
+
+test "array elisions as function parameters", ->
+  arr = [1,2,3,4,5,6,7,8,9]
+  foo = ([,a]) -> a
+  a = foo arr
+  eq a, 2
+  foo = ([,,,a]) -> a
+  a = foo arr
+  eq a, 4
+  foo = ([,a,,b,,c,,,d]) -> [a,b,c,d]
+  [a,b,c,d] = foo arr
+  arrayEq [a,b,c,d], [2,4,6,9]
+
+test "array elisions nested destructuring", ->
+  arr = [
+    1,
+    [2,3, [4,5,6, [7,8,9] ] ]
+  ]
+  [,a] = arr
+  arrayEq a[2][3], [7,8,9]
+  [,[,,[,b,,[,,c]]]] = arr
+  eq b, 5
+  eq c, 9
+  aobj = [
+    {},
+    {x: 2},
+    {},
+    [
+      {},
+      {},
+      {z:1, w:[1,2,4], p:3, q:4}
+      {},
+      {}
+    ]
+  ]
+  [,d,,[,,{w}]] = aobj
+  deepEqual d, {x:2}
+  arrayEq w, [1,2,4]
 
 # Splats in Array Literals
 

test/assignment.coffee

@@ -178,6 +178,13 @@ test "#713: destructuring assignment should return right-hand-side value", ->
   eq nonceB, b
   eq nonceB, d
 
+test "#4787 destructuring of objects within arrays", ->
+  arr = [1, {a:1, b:2}]
+  [...,{a, b}] = arr
+  eq a, 1
+  eq b, arr[1].b
+  deepEqual {a, b}, arr[1]
+
 test "destructuring assignment with splats", ->
   a = {}; b = {}; c = {}; d = {}; e = {}
   [x,y...,z] = [a,b,c,d,e]
@@ -246,311 +253,6 @@ test "destructuring assignment against an expression", ->
   eq a, y
   eq b, z
 
-test "destructuring assignment with objects and splats: ES2015", ->
-  obj = {a: 1, b: 2, c: 3, d: 4, e: 5}
-  throws (-> CoffeeScript.compile "{a, r..., s...} = x"), null, "multiple rest elements are disallowed"
-  throws (-> CoffeeScript.compile "{a, r..., s..., b} = x"), null, "multiple rest elements are disallowed"
-  prop = "b"
-  {a, b, r...} = obj
-  eq a, 1
-  eq b, 2
-  eq r.e, obj.e
-  eq r.a, undefined
-  {d, c: x, r...} = obj
-  eq x, 3
-  eq d, 4
-  eq r.c, undefined
-  eq r.b, 2
-  {a, 'b': z, g = 9, r...} = obj
-  eq g, 9
-  eq z, 2
-  eq r.b, undefined
-
-test "destructuring assignment with splats and default values", ->
-  obj = {}
-  c = {b: 1}
-  { a: {b} = c, d...} = obj
-
-  eq b, 1
-  deepEqual d, {}
-
-  # Should not trigger implicit call, e.g. rest ... => rest(...)
-  {
-    a: {b} = c
-    d ...
-  } = obj
-
-  eq b, 1
-  deepEqual d, {}
-
-test "destructuring assignment with splat with default value", ->
-  obj = {}
-  c = {val: 1}
-  { a: {b...} = c } = obj
-
-  deepEqual b, val: 1
-
-test "destructuring assignment with multiple splats in different objects", ->
-  obj = { a: {val: 1}, b: {val: 2} }
-  { a: {a...}, b: {b...} } = obj
-  deepEqual a, val: 1
-  deepEqual b, val: 2
-
-  o = {
-    props: {
-      p: {
-        n: 1
-        m: 5
-      }
-      s: 6
-    }
-  }
-  {p: {m, q..., t = {obj...}}, r...} = o.props
-  eq m, o.props.p.m
-  deepEqual r, s: 6
-  deepEqual q, n: 1
-  deepEqual t, obj
-
-  @props = o.props
-  {p: {m}, r...} = @props
-  eq m, @props.p.m
-  deepEqual r, s: 6
-
-  {p: {m}, r...} = {o.props..., p:{m:9}}
-  eq m, 9
-
-  # Should not trigger implicit call, e.g. rest ... => rest(...)
-  {
-    a: {
-      a ...
-    }
-    b: {
-      b ...
-    }
-  } = obj
-  deepEqual a, val: 1
-  deepEqual b, val: 2
-
-test "destructuring assignment with dynamic keys and splats", ->
-  i = 0
-  foo = -> ++i
-
-  obj = {1: 'a', 2: 'b'}
-  { "#{foo()}": a, b... } = obj
-
-  eq a, 'a'
-  eq i, 1
-  deepEqual b, 2: 'b'
-
-# Tests from https://babeljs.io/docs/plugins/transform-object-rest-spread/.
-test "destructuring assignment with objects and splats: Babel tests", ->
-  # What Babel calls “rest properties:”
-  { x, y, z... } = { x: 1, y: 2, a: 3, b: 4 }
-  eq x, 1
-  eq y, 2
-  deepEqual z, { a: 3, b: 4 }
-
-  # What Babel calls “spread properties:”
-  n = { x, y, z... }
-  deepEqual n, { x: 1, y: 2, a: 3, b: 4 }
-
-  # Should not trigger implicit call, e.g. rest ... => rest(...)
-  { x, y, z ... } = { x: 1, y: 2, a: 3, b: 4 }
-  eq x, 1
-  eq y, 2
-  deepEqual z, { a: 3, b: 4 }
-
-  n = { x, y, z ... }
-  deepEqual n, { x: 1, y: 2, a: 3, b: 4 }
-
-test "deep destructuring assignment with objects: ES2015", ->
-  a1={}; b1={}; c1={}; d1={}
-  obj = {
-    a: a1
-    b: {
-      'c': {
-        d: {
-          b1
-          e: c1
-          f: d1
-        }
-      }
-    }
-    b2: {b1, c1}
-  }
-  {a: w, b: {c: {d: {b1: bb, r1...}}}, r2...} = obj
-  eq r1.e, c1
-  eq r2.b, undefined
-  eq bb, b1
-  eq r2.b2, obj.b2
-
-  # Should not trigger implicit call, e.g. rest ... => rest(...)
-  {a: w, b: {c: {d: {b1: bb, r1 ...}}}, r2 ...} = obj
-  eq r1.e, c1
-  eq r2.b, undefined
-  eq bb, b1
-  eq r2.b2, obj.b2
-
-test "deep destructuring assignment with defaults: ES2015", ->
-  obj =
-    b: { c: 1, baz: 'qux' }
-    foo: 'bar'
-  j =
-    f: 'world'
-  i =
-    some: 'prop'
-  {
-    a...
-    b: { c, d... }
-    e: {
-      f: hello
-      g: { h... } = i
-    } = j
-  } = obj
-
-  deepEqual a, foo: 'bar'
-  eq c, 1
-  deepEqual d, baz: 'qux'
-  eq hello, 'world'
-  deepEqual h, some: 'prop'
-
-  # Should not trigger implicit call, e.g. rest ... => rest(...)
-  {
-    a ...
-    b: {
-      c,
-      d ...
-    }
-    e: {
-      f: hello
-      g: {
-        h ...
-      } = i
-    } = j
-  } = obj
-
-  deepEqual a, foo: 'bar'
-  eq c, 1
-  deepEqual d, baz: 'qux'
-  eq hello, 'world'
-  deepEqual h, some: 'prop'
-
-test "object spread properties: ES2015", ->
-  obj = {a: 1, b: 2, c: 3, d: 4, e: 5}
-  obj2 = {obj..., c:9}
-  eq obj2.c, 9
-  eq obj.a, obj2.a
-
-  # Should not trigger implicit call, e.g. rest ... => rest(...)
-  obj2 = {
-    obj ...
-    c:9
-  }
-  eq obj2.c, 9
-  eq obj.a, obj2.a
-
-  obj2 = {obj..., a: 8, c: 9, obj...}
-  eq obj2.c, 3
-  eq obj.a, obj2.a
-
-  # Should not trigger implicit call, e.g. rest ... => rest(...)
-  obj2 = {
-    obj ...
-    a: 8
-    c: 9
-    obj ...
-  }
-  eq obj2.c, 3
-  eq obj.a, obj2.a
-
-  obj3 = {obj..., b: 7, g: {obj2..., c: 1}}
-  eq obj3.g.c, 1
-  eq obj3.b, 7
-  deepEqual obj3.g, {obj..., c: 1}
-
-  (({a, b, r...}) ->
-    eq 1, a
-    deepEqual r, {c: 3, d: 44, e: 55}
-  ) {obj2..., d: 44, e: 55}
-
-  obj = {a: 1, b: 2, c: {d: 3, e: 4, f: {g: 5}}}
-  obj4 = {a: 10, obj.c...}
-  eq obj4.a, 10
-  eq obj4.d, 3
-  eq obj4.f.g, 5
-  deepEqual obj4.f, obj.c.f
-
-  # Should not trigger implicit call, e.g. rest ... => rest(...)
-  (({
-    a
-    b
-    r ...
-    }) ->
-    eq 1, a
-    deepEqual r, {c: 3, d: 44, e: 55}
-  ) {
-    obj2 ...
-    d: 44
-    e: 55
-  }
-
-  # Should not trigger implicit call, e.g. rest ... => rest(...)
-  obj4 = {
-    a: 10
-    obj.c ...
-  }
-  eq obj4.a, 10
-  eq obj4.d, 3
-  eq obj4.f.g, 5
-  deepEqual obj4.f, obj.c.f
-
-  obj5 = {obj..., ((k) -> {b: k})(99)...}
-  eq obj5.b, 99
-  deepEqual obj5.c, obj.c
-
-  # Should not trigger implicit call, e.g. rest ... => rest(...)
-  obj5 = {
-    obj ...
-    ((k) -> {b: k})(99) ...
-  }
-  eq obj5.b, 99
-  deepEqual obj5.c, obj.c
-
-  fn = -> {c: {d: 33, e: 44, f: {g: 55}}}
-  obj6 = {obj..., fn()...}
-  eq obj6.c.d, 33
-  deepEqual obj6.c, {d: 33, e: 44, f: {g: 55}}
-
-  obj7 = {obj..., fn()..., {c: {d: 55, e: 66, f: {77}}}...}
-  eq obj7.c.d, 55
-  deepEqual obj6.c, {d: 33, e: 44, f: {g: 55}}
-
-  # Should not trigger implicit call, e.g. rest ... => rest(...)
-  obj7 = {
-    obj ...
-    fn() ...
-    {c: {d: 55, e: 66, f: {77}}} ...
-  }
-  eq obj7.c.d, 55
-  deepEqual obj6.c, {d: 33, e: 44, f: {g: 55}}
-
-  obj =
-    a:
-      b:
-        c:
-          d:
-            e: {}
-  obj9 = {a:1, obj.a.b.c..., g:3}
-  deepEqual obj9.d, {e: {}}
-
-  a = "a"
-  c = "c"
-  obj9 = {a:1, obj[a].b[c]..., g:3}
-  deepEqual obj9.d, {e: {}}
-
-  obj9 = {a:1, obj.a["b"].c["d"]..., g:3}
-  deepEqual obj9["e"], {}
-
 test "bracket insertion when necessary", ->
   [a] = [0] ? [1]
   eq a, 0
@@ -898,32 +600,124 @@ test "#4566: destructuring with nested default values", ->
   {e: {f = 5} = {}} = {}
   eq 5, f
 
-test "#4674: _extends utility for object spreads 1", ->
-  eqJS(
-    "{a, b..., c..., d}"
-    """
-      var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };
+test "#4878: Compile error when using destructuring with a splat or expansion in an array", ->
+  arr = ['a', 'b', 'c', 'd']
 
-      _extends({a}, b, c, {d});
-    """
-  )
+  f1 = (list) ->
+    [first, ..., last] = list
 
-test "#4674: _extends utility for object spreads 2", ->
-  _extends = -> 3
-  a = b: 1
-  c = d: 2
-  e = {a..., c...}
-  eq e.b, 1
-  eq e.d, 2
+  f2 = (list) ->
+    [first..., last] = list
 
-test "#4673: complex destructured object spread variables", ->
-  b = c: 1
-  {{a...}...} = b
-  eq a.c, 1
+  f3 = (list) ->
+    ([first, ...] = list); first
 
-  d = {}
-  {d.e...} = f: 1
-  eq d.e.f, 1
+  f4 = (list) ->
+    ([first, rest...] = list); rest
 
-  {{g}...} = g: 1
-  eq g, 1
+  arrayEq f1(arr), arr
+  arrayEq f2(arr), arr
+  arrayEq f3(arr), 'a'
+  arrayEq f4(arr), ['b', 'c', 'd']
+
+  foo = (list) ->
+    ret =
+      if list?.length > 0
+        [first, ..., last] = list
+        [first, last]
+      else
+        []
+
+  arrayEq foo(arr), ['a', 'd']
+
+  bar = (list) ->
+    ret =
+      if list?.length > 0
+        [first, rest...] = list
+        [first, rest]
+      else
+        []
+
+  arrayEq bar(arr), ['a', ['b', 'c', 'd']]
+
+test "destructuring assignment with an empty array in object", ->
+  obj =
+    a1: [1, 2]
+    b1: 3
+
+  {a1:[], b1} = obj
+  eq 'undefined', typeof a1
+  eq b1, 3
+
+  obj =
+    a2:
+      b2: [1, 2]
+    c2: 3
+
+  {a2: {b2:[]}, c2} = obj
+  eq 'undefined', typeof b2
+  eq c2, 3
+
+test "#5004: array destructuring with accessors", ->
+  obj =
+    arr: ['a', 'b', 'c', 'd']
+    list: {}
+    f1: ->
+      [@first, @rest...] = @arr
+    f2: ->
+      [@second, @third..., @last] = @rest
+    f3: ->
+      [@list.a, @list.middle..., @list.d] = @arr
+
+  obj.f1()
+  eq obj.first, 'a'
+  arrayEq obj.rest, ['b', 'c', 'd']
+
+  obj.f2()
+  eq obj.second, 'b'
+  arrayEq obj.third, ['c']
+  eq obj.last, 'd'
+
+  obj.f3()
+  eq obj.list.a, 'a'
+  arrayEq obj.list.middle, ['b', 'c']
+  eq obj.list.d, 'd'
+
+  [obj.list.middle..., d] = obj.arr
+  eq d, 'd'
+  arrayEq obj.list.middle, ['a', 'b', 'c']
+
+test "#4884: destructured object splat", ->
+  [{length}...] = [1, 2, 3]
+  eq length, 3
+  [{length: len}...] = [1, 2, 3]
+  eq len, 3
+  [{length}..., three] = [1, 2, 3]
+  eq length, 2
+  eq three, 3
+  [{length: len}..., three] = [1, 2, 3]
+  eq len, 2
+  eq three, 3
+  x = [{length}..., three] = [1, 2, 3]
+  eq length, 2
+  eq three, 3
+  eq x[2], 3
+  x = [{length: len}..., three] = [1, 2, 3]
+  eq len, 2
+  eq three, 3
+  eq x[2], 3
+
+test "#4884: destructured array splat", ->
+  [[one, two, three]...] = [1, 2, 3]
+  eq one, 1
+  eq two, 2
+  eq three, 3
+  [[one, two]..., three] = [1, 2, 3]
+  eq one, 1
+  eq two, 2
+  eq three, 3
+  x = [[one, two]..., three] = [1, 2, 3]
+  eq one, 1
+  eq two, 2
+  eq three, 3
+  eq x[2], 3

test/async.coffee

@@ -1,8 +1,9 @@
 # Functions that contain the `await` keyword will compile into async functions,
 # supported by Node 7.6+, Chrome 55+, Firefox 52+, Safari 10.1+ and Edge.
-# But runtimes that don’t support the `await` keyword will throw an error,
-# even if we put `return unless global.supportsAsync` at the top of this file.
-# Therefore we need to prevent runtimes which will choke on such code from even
+# But runtimes that don’t support the `await` keyword will throw an error just
+# from parsing this file, even without executing it, even if we put
+# `return unless try new Function 'async () => {}'` at the top of this file.
+# Therefore we need to prevent runtimes which will choke on such code from
 # parsing it, which is handled in `Cakefile`.
 
 

test/async_iterators.coffee

@@ -0,0 +1,32 @@
+# This is always fulfilled.
+winLater = (val, ms) ->
+  new Promise (resolve) -> setTimeout (-> resolve val), ms
+
+# This is always rejected.
+failLater = (val, ms) ->
+  new Promise (resolve, reject) -> setTimeout (-> reject new Error val), ms
+
+createAsyncIterable = (syncIterable) ->
+  for elem in syncIterable
+    yield await winLater elem, 50
+
+test "async iteration", ->
+  foo = (x for await x from createAsyncIterable [1,2,3])
+  arrayEq foo, [1, 2, 3]
+
+test "async generator functions", ->
+  foo = (val) ->
+    yield await winLater val + 1, 50
+
+  bar = (val) ->
+    yield await failLater val - 1, 50
+
+  a = await foo(41).next()
+  eq a.value, 42
+
+  try
+    b = do -> await bar(41).next()
+    b.catch (err) ->
+      eq "40", err.message
+  catch err
+    ok no

test/classes.coffee

@@ -266,6 +266,7 @@ test "classes with value'd constructors", ->
     inner = ++counter
     ->
       @value = inner
+      @
 
   class One
     constructor: classMaker()
@@ -1857,3 +1858,45 @@ test "#4724: backticked expression in a class body with hoisted member", ->
   a = new A
   eq 42, a.x
   eq 84, a.hoisted
+
+test "#4822: nested anonymous classes use non-conflicting variable names", ->
+  Class = class
+    @a: class
+      @b: 1
+
+  eq Class.a.b, 1
+
+test "#4827: executable class body wrappers have correct context", ->
+  test = ->
+    class @A
+    class @B extends @A
+      @property = 1
+
+  o = {}
+  test.call o
+  ok typeof o.A is typeof o.B is 'function'
+
+test "#4868: Incorrect ‘Can’t call super with @params’ error", ->
+  class A
+    constructor: (@func = ->) ->
+      @x = 1
+      @func()
+
+  class B extends A
+    constructor: ->
+      super -> @x = 2
+
+  a = new A
+  b = new B
+  eq 1, a.x
+  eq 2, b.x
+
+  class C
+    constructor: (@c = class) -> @c
+
+  class D extends C
+    constructor: ->
+      super class then constructor: (@a) -> @a = 3
+
+  d = new (new D).c
+  eq 3, d.a

test/comments.coffee

@@ -364,7 +364,7 @@ test "#3132: Place block-comments nicely", ->
 
     return DummyClass;
 
-  })();"""
+  }).call(this);"""
 
 test "#3638: Demand a whitespace after # symbol", ->
   eqJS """

test/compilation.coffee

@@ -170,3 +170,10 @@ test "using transpile from the Node API requires an object", ->
 test "transpile option applies to imported .coffee files", ->
   return if global.testingBrowser
   doesNotThrow -> transpile 'run', "import { getSep } from './test/importing/transpile_import'\ngetSep()"
+
+test "#3306: trailing comma in a function call in the last line", ->
+  eqJS '''
+  foo bar,
+  ''', '''
+  foo(bar);
+  '''

test/control_flow.coffee

@@ -484,3 +484,828 @@ test "#4267: lots of for-loops in the same scope", ->
       true
   """
   ok CoffeeScript.eval(code)
+
+# Test for issue #2342: Lexer: Inline `else` binds to wrong `if`/`switch`
+test "#2343: if / then / if / then / else", ->
+  a = b = yes
+  c = e = g = no
+  d = 1
+  f = 2
+  h = 3
+  i = 4
+
+  s = ->
+    if a
+      if b
+        if c
+          d
+        else
+          if e
+            f
+          else
+            if g
+              h
+            else
+              i
+
+  t = ->
+    if a then if b
+      if c then d
+      else if e
+        f
+      else if g
+        h
+      else
+        i
+
+  u = ->
+    if a then if b
+      if c then d else if e
+        f
+      else if g
+        h
+      else i
+
+  v = ->
+    if a then if b
+      if c then d else if e then f
+      else if g then h
+      else i
+
+  w = ->
+    if a then if b
+      if c then d
+      else if e
+          f
+        else
+          if g then h
+          else i
+
+  x = -> if a then if b then if c then d else if e then f else if g then h else i
+
+  y = -> if a then if b then (if c then d else (if e then f else (if g then h else i)))
+
+  eq 4, s()
+  eq 4, t()
+  eq 4, u()
+  eq 4, v()
+  eq 4, w()
+  eq 4, x()
+  eq 4, y()
+
+  c = yes
+  eq 1, s()
+  eq 1, t()
+  eq 1, u()
+  eq 1, v()
+  eq 1, w()
+  eq 1, x()
+  eq 1, y()
+
+  b = no
+  eq undefined, s()
+  eq undefined, t()
+  eq undefined, u()
+  eq undefined, v()
+  eq undefined, w()
+  eq undefined, x()
+  eq undefined, y()
+
+test "#2343: if / then / if / then / else / else", ->
+  a = b = yes
+  c = e = g = no
+  d = 1
+  f = 2
+  h = 3
+  i = 4
+  j = 5
+  k = 6
+
+  s = ->
+    if a
+      if b
+        if c
+          d
+        else
+          e
+          if e
+            f
+          else
+            if g
+              h
+            else
+              i
+      else
+        j
+    else
+      k
+
+  t = ->
+    if a
+      if b
+        if c then d
+        else if e
+          f
+        else if g
+          h
+        else
+          i
+      else
+        j
+    else
+      k
+
+  u = ->
+    if a
+      if b
+        if c then d else if e
+          f
+        else if g
+          h
+        else i
+      else j
+    else k
+
+  v = ->
+    if a
+      if b
+        if c then d else if e then f
+        else if g then h
+        else i
+      else j else k
+
+  w = ->
+    if a then if b
+        if c then d
+        else if e
+            f
+          else
+            if g then h
+            else i
+    else j else k
+
+  x = -> if a then if b then if c then d else if e then f else if g then h else i else j else k
+
+  y = -> if a then (if b then (if c then d else (if e then f else (if g then h else i))) else j) else k
+
+  eq 4, s()
+  eq 4, t()
+  eq 4, u()
+  eq 4, v()
+  eq 4, w()
+  eq 4, x()
+  eq 4, y()
+
+  c = yes
+  eq 1, s()
+  eq 1, t()
+  eq 1, u()
+  eq 1, v()
+  eq 1, w()
+  eq 1, x()
+  eq 1, y()
+
+  b = no
+  eq 5, s()
+  eq 5, t()
+  eq 5, u()
+  eq 5, v()
+  eq 5, w()
+  eq 5, x()
+  eq 5, y()
+
+  a = no
+  eq 6, s()
+  eq 6, t()
+  eq 6, u()
+  eq 6, v()
+  eq 6, w()
+  eq 6, x()
+  eq 6, y()
+
+
+test "#2343: switch / when / then / if / then / else", ->
+  a = b = yes
+  c = e = g = no
+  d = 1
+  f = 2
+  h = 3
+  i = 4
+
+  s = ->
+    switch
+      when a
+        if b
+          if c
+            d
+          else
+            if e
+              f
+            else
+              if g
+                h
+              else
+                i
+
+
+  t = ->
+    switch
+      when a then if b
+        if c then d
+        else if e
+          f
+        else if g
+          h
+        else
+          i
+
+  u = ->
+    switch
+      when a then if b then if c then d
+      else if e then f
+      else if g then h else i
+
+  v = ->
+    switch
+      when a then if b then if c then d else if e then f
+      else if g then h else i
+
+  w = ->
+    switch
+      when a then if b then if c then d else if e then f
+      else if g
+        h
+      else i
+
+  x = ->
+    switch
+     when a then if b then if c then d else if e then f else if g then h else i
+
+  y = -> switch
+    when a then if b then (if c then d else (if e then f else (if g then h else i)))
+
+  eq 4, s()
+  eq 4, t()
+  eq 4, u()
+  eq 4, v()
+  eq 4, w()
+  eq 4, x()
+  eq 4, y()
+
+  c = yes
+  eq 1, s()
+  eq 1, t()
+  eq 1, u()
+  eq 1, v()
+  eq 1, w()
+  eq 1, x()
+  eq 1, y()
+
+  b = no
+  eq undefined, s()
+  eq undefined, t()
+  eq undefined, u()
+  eq undefined, v()
+  eq undefined, w()
+  eq undefined, x()
+  eq undefined, y()
+
+test "#2343: switch / when / then / if / then / else / else", ->
+  a = b = yes
+  c = e = g = no
+  d = 1
+  f = 2
+  h = 3
+  i = 4
+
+  s = ->
+    switch
+      when a
+        if b
+          if c
+            d
+          else if e
+            f
+          else if g
+            h
+          else
+            i
+      else
+        0
+
+  t = ->
+    switch
+      when a
+        if b
+          if c then d
+          else if e
+            f
+          else if g
+            h
+          else i
+      else 0
+
+  u = ->
+    switch
+      when a
+        if b then if c
+            d
+          else if e
+            f
+          else if g
+            h
+          else i
+      else 0
+
+  v = ->
+    switch
+      when a
+        if b then if c then d
+        else if e
+          f
+        else if g
+          h
+        else i
+      else 0
+
+  w = ->
+    switch
+      when a
+        if b then if c then d
+        else if e then f
+        else if g then h
+        else i
+      else 0
+
+  x = ->
+    switch
+     when a
+       if b then if c then d else if e then f else if g then h else i
+     else 0
+
+  y = -> switch
+    when a
+      if b then (if c then d else (if e then f else (if g then h else i)))
+    else 0
+
+  eq 4, s()
+  eq 4, t()
+  eq 4, u()
+  eq 4, v()
+  eq 4, w()
+  eq 4, x()
+  eq 4, y()
+
+  c = yes
+  eq 1, s()
+  eq 1, t()
+  eq 1, u()
+  eq 1, v()
+  eq 1, w()
+  eq 1, x()
+  eq 1, y()
+
+  b = no
+  eq undefined, s()
+  eq undefined, t()
+  eq undefined, u()
+  eq undefined, v()
+  eq undefined, w()
+  eq undefined, x()
+  eq undefined, y()
+
+  b = yes
+  a = no
+  eq 0, s()
+  eq 0, t()
+  eq 0, u()
+  eq 0, v()
+  eq 0, w()
+  eq 0, x()
+  eq 0, y()
+
+test "#2343: switch / when / then / if / then / else / else / else", ->
+  a = b = yes
+  c = e = g = no
+  d = 1
+  f = 2
+  h = 3
+  i = 4
+  j = 5
+
+  s = ->
+    switch
+      when a
+        if b
+          if c
+            d
+          else if e
+            f
+          else if g
+            h
+          else
+            i
+        else
+          j
+      else
+        0
+
+  t = ->
+    switch
+      when a
+        if b
+          if c then d
+          else if e
+            f
+          else if g
+            h
+          else i
+        else
+          j
+      else 0
+
+  u = ->
+    switch
+      when a
+        if b
+          if c
+            d
+          else if e
+            f
+          else if g
+            h
+          else i
+        else j
+      else 0
+
+  v = ->
+    switch
+      when a
+        if b
+          if c then d
+          else if e
+            f
+          else if g then h
+          else i
+        else j
+      else 0
+
+  w = ->
+    switch
+      when a
+        if b
+          if c then d
+          else if e then f
+          else if g then h
+          else i
+        else j
+      else 0
+
+  x = ->
+    switch
+     when a
+       if b then if c then d else if e then f else if g then h else i else j
+     else 0
+
+  y = -> switch
+    when a
+      if b then (if c then d else (if e then f else (if g then h else i))) else j
+    else 0
+
+  eq 4, s()
+  eq 4, t()
+  eq 4, u()
+  eq 4, v()
+  eq 4, w()
+  eq 4, x()
+  eq 4, y()
+
+  c = yes
+  eq 1, s()
+  eq 1, t()
+  eq 1, u()
+  eq 1, v()
+  eq 1, w()
+  eq 1, x()
+  eq 1, y()
+
+  b = no
+  eq 5, s()
+  eq 5, t()
+  eq 5, u()
+  eq 5, v()
+  eq 5, w()
+  eq 5, x()
+  eq 5, y()
+
+  b = yes
+  a = no
+  eq 0, s()
+  eq 0, t()
+  eq 0, u()
+  eq 0, v()
+  eq 0, w()
+  eq 0, x()
+  eq 0, y()
+
+# Test for issue #3921: Inline function without parentheses used in condition fails to compile
+test "#3921: `if` & `unless`", ->
+  a = {}
+  eq a, if do -> no then undefined else a
+  a1 = undefined
+  if do -> yes
+    a1 = a
+  eq a, a1
+
+  b = {}
+  eq b, unless do -> no then b else undefined
+  b1 = undefined
+  unless do -> no
+    b1 = b
+  eq b, b1
+
+  c = 0
+  if (arg = undefined) -> yes then c++
+  eq 1, c
+  d = 0
+  if (arg = undefined) -> yes
+    d++
+  eq 1, d
+
+  answer = 'correct'
+  eq answer, if do -> 'wrong' then 'correct' else 'wrong'
+  eq answer, unless do -> no then 'correct' else 'wrong'
+  statm1 = undefined
+  if do -> 'wrong'
+    statm1 = 'correct'
+  eq answer, statm1
+  statm2 = undefined
+  unless do -> no
+    statm2 = 'correct'
+  eq answer, statm2
+
+test "#3921: `post if`", ->
+  a = {}
+  eq a, a unless do -> no
+  a1 = a if do -> yes
+  eq a, a1
+
+  c = 0
+  c++ if (arg = undefined) -> yes
+  eq 1, c
+  d = 0
+  d++ if (arg = undefined) -> yes
+  eq 1, d
+
+  answer = 'correct'
+  eq answer, 'correct' if do -> 'wrong'
+  eq answer, 'correct' unless do -> not 'wrong'
+  statm1 = undefined
+  statm1 = 'correct' if do -> 'wrong'
+  eq answer, statm1
+  statm2 = undefined
+  statm2 = 'correct' unless do -> not 'wrong'
+  eq answer, statm2
+
+test "Issue 3921: `while` & `until`", ->
+  i = 5
+  assert = (a) -> ok 5 > a > 0
+  result1 = while do (num = 1) -> i -= num
+    assert i
+    i
+  ok result1.join(' ') is '4 3 2 1'
+
+  j = 5
+  result2 = until do (num = 1) -> (j -= num) < 1
+    assert j
+    j
+  ok result2.join(' ') is '4 3 2 1'
+
+test "#3921: `switch`", ->
+  i = 1
+  a = switch do (m = 2) -> i * m
+    when 5 then "five"
+    when 4 then "four"
+    when 3 then "three"
+    when 2 then "two"
+    when 1 then "one"
+    else "none"
+  eq "two", a
+
+  j = 12
+  b = switch do (m = 3) -> j / m
+    when 5 then "five"
+    when 4 then "four"
+    when 3 then "three"
+    when 2 then "two"
+    when 1 then "one"
+    else "none"
+  eq "four", b
+
+  k = 20
+  c = switch do (m = 4) -> k / m
+    when 5 then "five"
+    when 4 then "four"
+    when 3 then "three"
+    when 2 then "two"
+    when 1 then "one"
+    else "none"
+  eq "five", c
+
+# Issue #3909: backslash to break line in `for` loops throw syntax error
+test "#3909: backslash `for own ... of`", ->
+
+  obj = {a: 1, b: 2, c: 3}
+  arr = ['a', 'b', 'c']
+
+  x1 \
+    = ( key for own key of obj )
+  arrayEq x1, arr
+
+  x2 = \
+    ( key for own key of obj )
+  arrayEq x2, arr
+
+  x3 = ( \
+    key for own key of obj )
+  arrayEq x3, arr
+
+  x4 = ( key \
+    for own key of obj )
+  arrayEq x4, arr
+
+  x5 = ( key for own key of \
+    obj )
+  arrayEq x5, arr
+
+  x6 = ( key for own key of obj \
+    )
+  arrayEq x6, arr
+
+  x7 = ( key for \
+    own key of obj )
+  arrayEq x7, arr
+
+  x8 = ( key for own \
+    key of obj )
+  arrayEq x8, arr
+
+  x9 = ( key for own key \
+    of obj )
+  arrayEq x9, arr
+
+
+test "#3909: backslash `for ... of`", ->
+  obj = {a: 1, b: 2, c: 3}
+  arr = ['a', 'b', 'c']
+
+  x1 \
+    = ( key for key of obj )
+  arrayEq x1, arr
+
+  x2 = \
+    ( key for key of obj )
+  arrayEq x2, arr
+
+  x3 = ( \
+    key for key of obj )
+  arrayEq x3, arr
+
+  x4 = ( key \
+    for key of obj )
+  arrayEq x4, arr
+
+  x5 = ( key for key of \
+    obj )
+  arrayEq x5, arr
+
+  x6 = ( key for key of obj \
+    )
+  arrayEq x6, arr
+
+  x7 = ( key for \
+    key of obj )
+  arrayEq x7, arr
+
+  x8 = ( key for key \
+    of obj )
+  arrayEq x8, arr
+
+
+test "#3909: backslash `for ... in`", ->
+  arr = ['a', 'b', 'c']
+
+  x1 \
+    = ( key for key in arr )
+  arrayEq x1, arr
+
+  x2 = \
+    ( key for key in arr )
+  arrayEq x2, arr
+
+  x3 = ( \
+    key for key in arr )
+  arrayEq x3, arr
+
+  x4 = ( key \
+    for key in arr )
+  arrayEq x4, arr
+
+  x5 = ( key for key in \
+    arr )
+  arrayEq x5, arr
+
+  x6 = ( key for key in arr \
+    )
+  arrayEq x6, arr
+
+  x7 = ( key for \
+    key in arr )
+  arrayEq x7, arr
+
+  x8 = ( key for key \
+    in arr )
+  arrayEq x8, arr
+
+test "#4871: `else if` no longer output together ", ->
+   eqJS '''
+   if a then b else if c then d else if e then f else g
+   ''',
+   '''
+   if (a) {
+     b;
+   } else if (c) {
+     d;
+   } else if (e) {
+     f;
+   } else {
+     g;
+   }
+   '''
+
+   eqJS '''
+   if no
+     1
+   else if yes
+     2
+   ''',
+   '''
+   if (false) {
+     1;
+   } else if (true) {
+     2;
+   }
+   '''
+
+test "#4898: Lexer: backslash line continuation is inconsistent", ->
+  if ( \
+      false \
+      or \
+      true \
+    )
+    a = 42
+
+  eq a, 42
+
+  if ( \
+      false \
+      or \
+      true \
+  )
+    b = 42
+
+  eq b, 42
+
+  if ( \
+            false \
+         or \
+   true \
+  )
+    c = 42
+
+  eq c, 42
+
+  if \
+   false \
+        or \
+   true
+    d = 42
+
+  eq d, 42
+
+  if \
+              false or \
+  true
+    e = 42
+
+  eq e, 42
+
+  if \
+       false or \
+    true \
+       then \
+   f = 42 \
+   else
+     f = 24
+
+  eq f, 42

test/csx.coffee

@@ -742,3 +742,47 @@ test '#4686: comments inside interpolations that also contain CSX attributes', -
     </div>;
   '''
 
+# https://reactjs.org/blog/2017/11/28/react-v16.2.0-fragment-support.html
+test 'JSX fragments: empty fragment', ->
+  eqJS '''
+    <></>
+  ''', '''
+    <></>;
+  '''
+
+test 'JSX fragments: fragment with text nodes', ->
+  eqJS '''
+    <>
+      Some text.
+      <h2>A heading</h2>
+      More text.
+      <h2>Another heading</h2>
+      Even more text.
+    </>
+  ''', '''
+    <>
+      Some text.
+      <h2>A heading</h2>
+      More text.
+      <h2>Another heading</h2>
+      Even more text.
+    </>;
+  '''
+
+test 'JSX fragments: fragment with component nodes', ->
+  eqJS '''
+   Component = (props) =>
+     <Fragment>
+       <OtherComponent />
+       <OtherComponent />
+     </Fragment>
+  ''', '''
+    var Component;
+
+    Component = (props) => {
+      return <Fragment>
+        <OtherComponent />
+        <OtherComponent />
+      </Fragment>;
+    };
+  '''

test/error_messages.coffee

@@ -183,9 +183,9 @@ test "#1096: unexpected generated tokens", ->
     for i in [1]:
       1
   ''', '''
-    [stdin]:1:10: error: unexpected [
-    for i in [1]:
-             ^
+    [stdin]:2:4: error: unexpected end of input
+      1
+       ^
   '''
   # Unexpected regex
   assertErrorFormat '{/a/i: val}', '''
@@ -808,29 +808,8 @@ test "invalid numbers", ->
     ^^^
 '''
 
-test "unexpected object keys", ->
-  assertErrorFormat '''
-    {[[]]}
-  ''', '''
-    [stdin]:1:2: error: unexpected [
-    {[[]]}
-     ^
-  '''
-  assertErrorFormat '''
-    {[[]]: 1}
-  ''', '''
-    [stdin]:1:2: error: unexpected [
-    {[[]]: 1}
-     ^
-  '''
-  assertErrorFormat '''
-    [[]]: 1
-  ''', '''
-    [stdin]:1:1: error: unexpected [
-    [[]]: 1
-    ^
-  '''
 
+test "unexpected object keys", ->
   assertErrorFormat '''
     {(a + "b")}
   ''', '''
@@ -852,20 +831,6 @@ test "unexpected object keys", ->
     (a + "b"): 1
              ^
   '''
-  assertErrorFormat '''
-    a: 1, [[]]: 2
-  ''', '''
-    [stdin]:1:7: error: unexpected [
-    a: 1, [[]]: 2
-          ^
-  '''
-  assertErrorFormat '''
-    {a: 1, [[]]: 2}
-  ''', '''
-    [stdin]:1:8: error: unexpected [
-    {a: 1, [[]]: 2}
-           ^
-  '''
 
 test "invalid object keys", ->
   assertErrorFormat '''
@@ -997,6 +962,42 @@ test "#4097: `yield return` as an expression", ->
         ^^^^^^^^^^^^
   '''
 
+test "#5013: `await return` as an expression", ->
+  assertErrorFormat '''
+    -> (await return)
+  ''', '''
+    [stdin]:1:5: error: cannot use a pure statement in an expression
+    -> (await return)
+        ^^^^^^^^^^^^
+  '''
+
+test "#5013: `return` as an expression", ->
+  assertErrorFormat '''
+    -> (return)
+  ''', '''
+    [stdin]:1:5: error: cannot use a pure statement in an expression
+    -> (return)
+        ^^^^^^
+  '''
+
+test "#5013: `break` as an expression", ->
+  assertErrorFormat '''
+    (b = 1; break) for b in a
+  ''', '''
+    [stdin]:1:9: error: cannot use a pure statement in an expression
+    (b = 1; break) for b in a
+            ^^^^^
+  '''
+
+test "#5013: `continue` as an expression", ->
+  assertErrorFormat '''
+    (b = 1; continue) for b in a
+  ''', '''
+    [stdin]:1:9: error: cannot use a pure statement in an expression
+    (b = 1; continue) for b in a
+            ^^^^^^^^
+  '''
+
 test "`&&=` and `||=` with a space in-between", ->
   assertErrorFormat '''
     a = 0
@@ -1197,6 +1198,18 @@ test "bound functions cannot be generators", ->
            ^^^^^^^^^^
   '''
 
+test "#4790: bound functions cannot be generators, even when we’re creating IIFEs", ->
+  assertErrorFormat '''
+  =>
+    for x in []
+      for y in []
+        yield z
+  ''', '''
+    [stdin]:4:7: error: yield cannot occur inside bound (fat arrow) functions
+          yield z
+          ^^^^^^^
+  '''
+
 test "CoffeeScript keywords cannot be used as unaliased names in import lists", ->
   assertErrorFormat """
     import { unless, baz as bar } from 'lib'
@@ -1217,28 +1230,6 @@ test "CoffeeScript keywords cannot be used as local names in import list aliases
                     ^^^^^^
   '''
 
-test "function cannot contain both `await` and `yield`", ->
-  assertErrorFormat '''
-    f = () ->
-      yield 5
-      await a
-  ''', '''
-    [stdin]:3:3: error: function can't contain both yield and await
-      await a
-      ^^^^^^^
-  '''
-
-test "function cannot contain both `await` and `yield from`", ->
-  assertErrorFormat '''
-    f = () ->
-      yield from a
-      await b
-  ''', '''
-    [stdin]:3:3: error: function can't contain both yield and await
-      await b
-      ^^^^^^^
-  '''
-
 test "cannot have `await` outside a function", ->
   assertErrorFormat '''
     await 1
@@ -1791,3 +1782,62 @@ test "#3098: suppressed newline should be unsuppressed by semicolon", ->
     a = ; 5
         ^
   '''
+
+test "#4811: '///' inside a heregex comment does not close the heregex", ->
+  assertErrorFormat '''
+   /// .* # comment ///
+  ''', '''
+  [stdin]:1:1: error: missing ///
+  /// .* # comment ///
+  ^^^
+  '''
+
+test "#3933: prevent implicit calls when cotrol flow is missing `THEN`", ->
+  assertErrorFormat '''
+    for a in b do ->
+  ''','''
+    [stdin]:1:12: error: unexpected do
+    for a in b do ->
+               ^^
+  '''
+
+  assertErrorFormat '''
+    for a in b ->
+  ''','''
+    [stdin]:1:12: error: unexpected ->
+    for a in b ->
+               ^^
+  '''
+
+  assertErrorFormat '''
+    for a in b do =>
+  ''','''
+    [stdin]:1:12: error: unexpected do
+    for a in b do =>
+               ^^
+  '''
+
+  assertErrorFormat '''
+    while a do ->
+  ''','''
+    [stdin]:1:9: error: unexpected do
+    while a do ->
+            ^^
+  '''
+
+  assertErrorFormat '''
+    until a do =>
+  ''','''
+    [stdin]:1:9: error: unexpected do
+    until a do =>
+            ^^
+  '''
+
+  assertErrorFormat '''
+    switch
+      when a ->
+  ''','''
+    [stdin]:2:10: error: unexpected ->
+      when a ->
+             ^^
+  '''

test/exception_handling.coffee

@@ -8,7 +8,7 @@ nonce = {}
 # Throw
 
 test "basic exception throwing", ->
-  throws (-> throw 'error'), 'error'
+  throws (-> throw 'error'), /^error$/
 
 
 # Empty Try/Catch/Finally

test/exponentiation.coffee

@@ -0,0 +1,19 @@
+# The `**` and `**=` operators are only supported in Node 7.5+, so the tests
+# for these exponentiation operators are split out into their own file to be
+# loaded only by supported runtimes.
+
+test "exponentiation operator", ->
+  eq 27, 3 ** 3
+
+test "exponentiation operator has higher precedence than other maths operators", ->
+  eq 55, 1 + 3 ** 3 * 2
+  eq -4, -2 ** 2
+  eq 0, (!2) ** 2
+
+test "exponentiation operator is right associative", ->
+  eq 2, 2 ** 1 ** 3
+
+test "exponentiation operator compound assignment", ->
+  a = 2
+  a **= 3
+  eq 8, a

test/function_invocation.coffee

@@ -329,6 +329,15 @@ test "Simple Destructuring function arguments with same-named variables in scope
   eq f([2]), 2
   eq x, 1
 
+test "#4843: Bad output when assigning to @prop in destructuring assignment with defaults", ->
+  works = "maybe"
+  drinks = "beer"
+  class A
+    constructor: ({@works = 'no', @drinks = 'wine'}) ->
+  a = new A {works: 'yes', drinks: 'coffee'}
+  eq a.works, 'yes'
+  eq a.drinks, 'coffee'
+
 test "caching base value", ->
 
   obj =
@@ -795,7 +804,7 @@ test "get and set can be used as class method names", ->
   eq 4, B.get()
   eq 5, B.set()
 
-test "functions named get or set can be used without parentheses when attached to an object; #4524", ->
+test "#4524: functions named get or set can be used without parentheses when attached to an object", ->
   obj =
     get: (x) -> x + 2
     set: (x) -> x + 3
@@ -814,6 +823,8 @@ test "functions named get or set can be used without parentheses when attached t
 
   eq 12, obj.get 10
   eq 13, obj.set 10
+  eq 12, obj?.get 10
+  eq 13, obj?.set 10
 
   eq 14, a.get 10
   eq 15, a.set 10
@@ -836,3 +847,59 @@ test "functions named get or set can be used without parentheses when attached t
 
   eq 16, b.get value: @ten
   eq 17, b.set value: @ten
+
+test "#4836: functions named get or set can be used without parentheses when attached to this or @", ->
+  @get = (x) -> x + 2
+  @set = (x) -> x + 3
+  @a = 4
+
+  eq 12, this.get 10
+  eq 13, this.set 10
+  eq 12, this?.get 10
+  eq 13, this?.set 10
+  eq 6, this.get @a
+  eq 7, this.set @a
+  eq 6, this?.get @a
+  eq 7, this?.set @a
+
+  eq 12, @get 10
+  eq 13, @set 10
+  eq 12, @?.get 10
+  eq 13, @?.set 10
+  eq 6, @get @a
+  eq 7, @set @a
+  eq 6, @?.get @a
+  eq 7, @?.set @a
+
+test "#4852: functions named get or set can be used without parentheses when attached to this or @, with an argument of an implicit object", ->
+  @get = ({ x }) -> x + 2
+  @set = ({ x }) -> x + 3
+
+  eq 12, @get x: 10
+  eq 13, @set x: 10
+  eq 12, @?.get x: 10
+  eq 13, @?.set x: 10
+  eq 12, this?.get x: 10
+  eq 13, this?.set x: 10
+
+test "#4473: variable scope in chained calls", ->
+  obj =
+    foo: -> this
+    bar: (a) ->
+      a()
+      this
+
+  obj.foo(a = 1).bar(-> a = 2)
+  eq a, 2
+
+  obj.bar(-> b = 2).foo(b = 1)
+  eq b, 1
+
+  obj.foo(c = 1).bar(-> c = 2).foo(c = 3)
+  eq c, 3
+
+  obj.foo([d, e] = [1, 2]).bar(-> d = 4)
+  eq d, 4
+
+  obj.foo({f} = {f: 1}).bar(-> f = 5)
+  eq f, 5

test/functions.coffee

@@ -127,6 +127,16 @@ test "destructured splatted parameters", ->
   splatArray = ([a ...]) -> a
   splatArrayRest = ([a ...],b ...) -> arrayEq(a,b); b
 
+test "#4884: object-destructured splatted parameters", ->
+  f = ({length}...) -> length
+  eq f(4, 5, 6), 3
+  f = ({length: len}...) -> len
+  eq f(4, 5, 6), 3
+  f = ({length}..., last) -> [length, last]
+  arrayEq f(4, 5, 6), [2, 6]
+  f = ({length: len}..., last) -> [len, last]
+  arrayEq f(4, 5, 6), [2, 6]
+
 test "@-parameters: automatically assign an argument's value to a property of the context", ->
   nonce = {}
 
@@ -215,86 +225,6 @@ test "destructuring in function definition", ->
     url: '/home', async: true, beforeSend: fn, cache: true, method: 'post', data: {}
   }
 
-test "rest element destructuring in function definition", ->
-  obj = {a: 1, b: 2, c: 3, d: 4, e: 5}
-
-  (({a, b, r...}) ->
-    eq 1, a
-    eq 2, b,
-    deepEqual r, {c: 3, d: 4, e: 5}
-  ) obj
-
-  (({a: p, b, r...}, q) ->
-    eq p, 1
-    eq q, 9
-    deepEqual r, {c: 3, d: 4, e: 5}
-  ) {a:1, b:2, c:3, d:4, e:5}, 9
-
-  # Should not trigger implicit call, e.g. rest ... => rest(...)
-  (({
-      a: p
-      b
-      r ...
-    }, q) ->
-    eq p, 1
-    eq q, 9
-    deepEqual r, {c: 3, d: 4, e: 5}
-  ) {a:1, b:2, c:3, d:4, e:5}, 9
-
-  a1={}; b1={}; c1={}; d1={}
-  obj1 = {
-    a: a1
-    b: {
-      'c': {
-        d: {
-          b1
-          e: c1
-          f: d1
-        }
-      }
-    }
-    b2: {b1, c1}
-  }
-
-  (({a: w, b: {c: {d: {b1: bb, r1...}}}, r2...}) ->
-    eq a1, w
-    eq bb, b1
-    eq r2.b, undefined
-    deepEqual r1, {e: c1, f: d1}
-    deepEqual r2.b2, {b1, c1}
-  ) obj1
-
-  b = 3
-  f = ({a, b...}) ->
-  f {}
-  eq 3, b
-
-  (({a, r...} = {}) ->
-    eq a, undefined
-    deepEqual r, {}
-  )()
-
-  (({a, r...} = {}) ->
-    eq a, 1
-    deepEqual r, {b: 2, c: 3}
-  ) {a: 1, b: 2, c: 3}
-
-  f = ({a, r...} = {}) -> [a, r]
-  deepEqual [undefined, {}], f()
-  deepEqual [1, {b: 2}], f {a: 1, b: 2}
-  deepEqual [1, {}], f {a: 1}
-
-  f = ({a, r...} = {a: 1, b: 2}) -> [a, r]
-  deepEqual [1, {b:2}], f()
-  deepEqual [2, {}], f {a:2}
-  deepEqual [3, {c:5}], f {a:3, c:5}
-
-  f = ({ a: aa = 0, b: bb = 0 }) -> [aa, bb]
-  deepEqual [0, 0], f {}
-  deepEqual [0, 42], f {b:42}
-  deepEqual [42, 0], f {a:42}
-  deepEqual [42, 43], f {a:42, b:43}
-
 test "#4005: `([a = {}]..., b) ->` weirdness", ->
   fn = ([a = {}]..., b) -> [a, b]
   deepEqual fn(5), [{}, 5]
@@ -550,15 +480,6 @@ test "#4413: expressions in function parameters that create generated variables
   eq f(), 33
   eq g(), 34
 
-test "#4673: complex destructured object spread variables", ->
-  f = ({{a...}...}) ->
-    a
-  eq f(c: 1).c, 1
-
-  g = ({@y...}) ->
-    eq @y.b, 1
-  g b: 1
-
 test "#4657: destructured array param declarations", ->
   a = 1
   b = 2

test/generators.coffee

@@ -168,7 +168,7 @@ test "`throw` can be yielded", ->
   throws -> x.next()
 
 test "symbolic operators has precedence over the `yield`", ->
-  symbolic   = '+ - * / << >> & | || && ** ^ // or and'.split ' '
+  symbolic   = '+ - * / << >> & | || && ^ // or and'.split ' '
   compound   = ("#{op}=" for op in symbolic)
   relations  = '< > == != <= >= is isnt'.split ' '
 

test/interpolation.coffee

@@ -139,7 +139,7 @@ eq 'multiline nested "interpolations" work', """multiline #{
 
 eq 'function(){}', "#{->}".replace /\s/g, ''
 ok /^a[\s\S]+b$/.test "a#{=>}b"
-ok /^a[\s\S]+b$/.test "a#{ (x) -> x ** 2 }b"
+ok /^a[\s\S]+b$/.test "a#{ (x) -> x %% 2 }b"
 
 # Regular Expression Interpolation
 

test/invocation_argument_parsing.coffee

@@ -6,6 +6,8 @@ path = require 'path'
 # Get the folder containing the compiled `coffee` executable and make it the
 # PATH so that `#!/usr/bin/env coffee` resolves to our locally built file.
 coffeeBinFolder = path.dirname require.resolve '../bin/coffee'
+# For some reason, Windows requires `coffee` to be executed as `node coffee`.
+coffeeCommand = if isWindows() then 'node coffee' else 'coffee'
 spawnOptions =
   cwd: coffeeBinFolder
   encoding: 'utf8'
@@ -18,7 +20,7 @@ initialSpaceScript = require.resolve './importing/shebang_initial_space.coffee'
 extraArgsScript = require.resolve './importing/shebang_extra_args.coffee'
 initialSpaceExtraArgsScript = require.resolve './importing/shebang_initial_space_extra_args.coffee'
 
-test "parse arguments for shebang scripts correctly (on unix platforms)", ->
+test "parse arguments for shebang scripts correctly (on *nix platforms)", ->
   return if isWindows()
 
   stdout = execFileSync shebangScript, ['-abck'], spawnOptions
@@ -32,7 +34,7 @@ test "parse arguments for shebang scripts correctly (on unix platforms)", ->
   arrayEq expectedArgs, realArgs
 
 test "warn and remove -- if it is the second positional argument", ->
-  result = spawnSync 'coffee', [shebangScript, '--'], spawnOptions
+  result = spawnSync coffeeCommand, [shebangScript, '--'], spawnOptions
   stderr = result.stderr.toString()
   arrayEq JSON.parse(result.stdout), ['coffee', shebangScript]
   ok stderr.match /^coffee was invoked with '--'/m
@@ -40,7 +42,7 @@ test "warn and remove -- if it is the second positional argument", ->
   arrayEq JSON.parse(posArgs), [shebangScript, '--']
   ok result.status is 0
 
-  result = spawnSync 'coffee', ['-b', shebangScript, '--'], spawnOptions
+  result = spawnSync coffeeCommand, ['-b', shebangScript, '--'], spawnOptions
   stderr = result.stderr.toString()
   arrayEq JSON.parse(result.stdout), ['coffee', shebangScript]
   ok stderr.match /^coffee was invoked with '--'/m
@@ -49,7 +51,7 @@ test "warn and remove -- if it is the second positional argument", ->
   ok result.status is 0
 
   result = spawnSync(
-    'coffee', ['-b', shebangScript, '--', 'ANOTHER'], spawnOptions)
+    coffeeCommand, ['-b', shebangScript, '--', 'ANOTHER'], spawnOptions)
   stderr = result.stderr.toString()
   arrayEq JSON.parse(result.stdout), ['coffee', shebangScript, 'ANOTHER']
   ok stderr.match /^coffee was invoked with '--'/m
@@ -58,7 +60,7 @@ test "warn and remove -- if it is the second positional argument", ->
   ok result.status is 0
 
   result = spawnSync(
-    'coffee', ['--', initialSpaceScript, 'arg'], spawnOptions)
+    coffeeCommand, ['--', initialSpaceScript, 'arg'], spawnOptions)
   expectedArgs = ['coffee', initialSpaceScript, 'arg']
   realArgs = JSON.parse result.stdout
   arrayEq expectedArgs, realArgs
@@ -66,7 +68,7 @@ test "warn and remove -- if it is the second positional argument", ->
   ok result.status is 0
 
 test "warn about non-portable shebang lines", ->
-  result = spawnSync 'coffee', [extraArgsScript, 'arg'], spawnOptions
+  result = spawnSync coffeeCommand, [extraArgsScript, 'arg'], spawnOptions
   stderr = result.stderr.toString()
   arrayEq JSON.parse(result.stdout), ['coffee', extraArgsScript, 'arg']
   ok stderr.match /^The script to be run begins with a shebang line with more than one/m
@@ -77,14 +79,14 @@ test "warn about non-portable shebang lines", ->
   arrayEq JSON.parse(args), ['coffee', '--']
   ok result.status is 0
 
-  result = spawnSync 'coffee', [initialSpaceScript, 'arg'], spawnOptions
+  result = spawnSync coffeeCommand, [initialSpaceScript, 'arg'], spawnOptions
   stderr = result.stderr.toString()
   ok stderr is ''
   arrayEq JSON.parse(result.stdout), ['coffee', initialSpaceScript, 'arg']
   ok result.status is 0
 
   result = spawnSync(
-    'coffee', [initialSpaceExtraArgsScript, 'arg'], spawnOptions)
+    coffeeCommand, [initialSpaceExtraArgsScript, 'arg'], spawnOptions)
   stderr = result.stderr.toString()
   arrayEq JSON.parse(result.stdout), ['coffee', initialSpaceExtraArgsScript, 'arg']
   ok stderr.match /^The script to be run begins with a shebang line with more than one/m
@@ -97,7 +99,7 @@ test "warn about non-portable shebang lines", ->
 
 test "both warnings will be shown at once", ->
   result = spawnSync(
-    'coffee', [initialSpaceExtraArgsScript, '--', 'arg'], spawnOptions)
+    coffeeCommand, [initialSpaceExtraArgsScript, '--', 'arg'], spawnOptions)
   stderr = result.stderr.toString()
   arrayEq JSON.parse(result.stdout), ['coffee', initialSpaceExtraArgsScript, 'arg']
   ok stderr.match /^The script to be run begins with a shebang line with more than one/m

test/modules.coffee

@@ -329,7 +329,7 @@ test "export default implicit object", ->
 test "export default multiline implicit object", ->
   eqJS """
     export default
-      foo: 'bar',
+      foo: 'bar'
       baz: 'qux'
     """,
   """
@@ -338,6 +338,22 @@ test "export default multiline implicit object", ->
       baz: 'qux'
     };"""
 
+test "export default multiline implicit object with internal braces", ->
+  eqJS """
+    export default
+      foo: yes
+      bar: {
+        baz
+      }
+      quz: no
+    """,
+  """
+    export default {
+      foo: true,
+      bar: {baz},
+      quz: false
+    };"""
+
 test "export default assignment expression", ->
   eqJS "export default foo = 'bar'",
   """
@@ -837,3 +853,70 @@ test "#4491: import- and export-specific lexing should stop after import/export
 
     from('foo');
     """
+
+# Issue #4874: Backslash not supported in import or export statements
+test "#4874: backslash `import`", ->
+
+  eqJS """
+    import foo \
+        from 'lib'
+
+    foo a
+    """,
+  """
+    import foo from 'lib';
+
+    foo(a);
+    """
+
+  eqJS """
+    import \
+                    foo \
+        from \
+    'lib'
+
+    foo a
+    """,
+  """
+    import foo from 'lib';
+
+    foo(a);
+    """
+
+  eqJS """
+    import \
+          utilityBelt \
+    , {
+      each
+    } from \
+    'underscore'
+    """,
+  """
+    import utilityBelt, {
+      each
+    } from 'underscore';
+    """
+
+test "#4874: backslash `export`", ->
+  eqJS """
+    export \
+      * \
+            from \
+      'underscore'
+    """,
+  """
+    export * from 'underscore';
+    """
+
+  eqJS """
+    export \
+        { max, min } \
+              from \
+      'underscore'
+  """,
+  """
+    export {
+      max,
+      min
+    } from 'underscore';
+    """

test/object_rest_spread.coffee

@@ -0,0 +1,420 @@
+test "#4798 destructuring of objects with splat within arrays", ->
+  arr = [1, {a:1, b:2}]
+  [...,{a, r...}] = arr
+  eq a, 1
+  deepEqual r, {b:2}
+  [b, {q...}] = arr
+  eq b, 1
+  deepEqual q, arr[1]
+  eq q.b, r.b
+  eq q.a, a
+
+  arr2 = [arr[1]]
+  [{a2...}] = arr2
+  eq a2.a, arr2[0].a
+
+test "destructuring assignment with objects and splats: ES2015", ->
+  obj = {a: 1, b: 2, c: 3, d: 4, e: 5}
+  throws (-> CoffeeScript.compile "{a, r..., s...} = x"), null, "multiple rest elements are disallowed"
+  throws (-> CoffeeScript.compile "{a, r..., s..., b} = x"), null, "multiple rest elements are disallowed"
+  prop = "b"
+  {a, b, r...} = obj
+  eq a, 1
+  eq b, 2
+  eq r.e, obj.e
+  eq r.a, undefined
+  {d, c: x, r...} = obj
+  eq x, 3
+  eq d, 4
+  eq r.c, undefined
+  eq r.b, 2
+  {a, 'b': z, g = 9, r...} = obj
+  eq g, 9
+  eq z, 2
+  eq r.b, undefined
+
+test "destructuring assignment with splats and default values", ->
+  obj = {}
+  c = {b: 1}
+  { a: {b} = c, d...} = obj
+
+  eq b, 1
+  deepEqual d, {}
+
+  # Should not trigger implicit call, e.g. rest ... => rest(...)
+  {
+    a: {b} = c
+    d ...
+  } = obj
+
+  eq b, 1
+  deepEqual d, {}
+
+test "destructuring assignment with splat with default value", ->
+  obj = {}
+  c = {val: 1}
+  { a: {b...} = c } = obj
+
+  deepEqual b, val: 1
+
+test "destructuring assignment with multiple splats in different objects", ->
+  obj = { a: {val: 1}, b: {val: 2} }
+  { a: {a...}, b: {b...} } = obj
+  deepEqual a, val: 1
+  deepEqual b, val: 2
+
+  o = {
+    props: {
+      p: {
+        n: 1
+        m: 5
+      }
+      s: 6
+    }
+  }
+  {p: {m, q..., t = {obj...}}, r...} = o.props
+  eq m, o.props.p.m
+  deepEqual r, s: 6
+  deepEqual q, n: 1
+  deepEqual t, obj
+
+  @props = o.props
+  {p: {m}, r...} = @props
+  eq m, @props.p.m
+  deepEqual r, s: 6
+
+  {p: {m}, r...} = {o.props..., p:{m:9}}
+  eq m, 9
+
+  # Should not trigger implicit call, e.g. rest ... => rest(...)
+  {
+    a: {
+      a ...
+    }
+    b: {
+      b ...
+    }
+  } = obj
+  deepEqual a, val: 1
+  deepEqual b, val: 2
+
+test "destructuring assignment with dynamic keys and splats", ->
+  i = 0
+  foo = -> ++i
+
+  obj = {1: 'a', 2: 'b'}
+  { "#{foo()}": a, b... } = obj
+
+  eq a, 'a'
+  eq i, 1
+  deepEqual b, 2: 'b'
+
+# Tests from https://babeljs.io/docs/plugins/transform-object-rest-spread/.
+test "destructuring assignment with objects and splats: Babel tests", ->
+  # What Babel calls “rest properties:”
+  { x, y, z... } = { x: 1, y: 2, a: 3, b: 4 }
+  eq x, 1
+  eq y, 2
+  deepEqual z, { a: 3, b: 4 }
+
+  # What Babel calls “spread properties:”
+  n = { x, y, z... }
+  deepEqual n, { x: 1, y: 2, a: 3, b: 4 }
+
+  # Should not trigger implicit call, e.g. rest ... => rest(...)
+  { x, y, z ... } = { x: 1, y: 2, a: 3, b: 4 }
+  eq x, 1
+  eq y, 2
+  deepEqual z, { a: 3, b: 4 }
+
+  n = { x, y, z ... }
+  deepEqual n, { x: 1, y: 2, a: 3, b: 4 }
+
+test "deep destructuring assignment with objects: ES2015", ->
+  a1={}; b1={}; c1={}; d1={}
+  obj = {
+    a: a1
+    b: {
+      'c': {
+        d: {
+          b1
+          e: c1
+          f: d1
+        }
+      }
+    }
+    b2: {b1, c1}
+  }
+  {a: w, b: {c: {d: {b1: bb, r1...}}}, r2...} = obj
+  eq r1.e, c1
+  eq r2.b, undefined
+  eq bb, b1
+  eq r2.b2, obj.b2
+
+  # Should not trigger implicit call, e.g. rest ... => rest(...)
+  {a: w, b: {c: {d: {b1: bb, r1 ...}}}, r2 ...} = obj
+  eq r1.e, c1
+  eq r2.b, undefined
+  eq bb, b1
+  eq r2.b2, obj.b2
+
+test "deep destructuring assignment with defaults: ES2015", ->
+  obj =
+    b: { c: 1, baz: 'qux' }
+    foo: 'bar'
+  j =
+    f: 'world'
+  i =
+    some: 'prop'
+  {
+    a...
+    b: { c, d... }
+    e: {
+      f: hello
+      g: { h... } = i
+    } = j
+  } = obj
+
+  deepEqual a, foo: 'bar'
+  eq c, 1
+  deepEqual d, baz: 'qux'
+  eq hello, 'world'
+  deepEqual h, some: 'prop'
+
+  # Should not trigger implicit call, e.g. rest ... => rest(...)
+  {
+    a ...
+    b: {
+      c,
+      d ...
+    }
+    e: {
+      f: hello
+      g: {
+        h ...
+      } = i
+    } = j
+  } = obj
+
+  deepEqual a, foo: 'bar'
+  eq c, 1
+  deepEqual d, baz: 'qux'
+  eq hello, 'world'
+  deepEqual h, some: 'prop'
+
+test "object spread properties: ES2015", ->
+  obj = {a: 1, b: 2, c: 3, d: 4, e: 5}
+  obj2 = {obj..., c:9}
+  eq obj2.c, 9
+  eq obj.a, obj2.a
+
+  # Should not trigger implicit call, e.g. rest ... => rest(...)
+  obj2 = {
+    obj ...
+    c:9
+  }
+  eq obj2.c, 9
+  eq obj.a, obj2.a
+
+  obj2 = {obj..., a: 8, c: 9, obj...}
+  eq obj2.c, 3
+  eq obj.a, obj2.a
+
+  # Should not trigger implicit call, e.g. rest ... => rest(...)
+  obj2 = {
+    obj ...
+    a: 8
+    c: 9
+    obj ...
+  }
+  eq obj2.c, 3
+  eq obj.a, obj2.a
+
+  obj3 = {obj..., b: 7, g: {obj2..., c: 1}}
+  eq obj3.g.c, 1
+  eq obj3.b, 7
+  deepEqual obj3.g, {obj..., c: 1}
+
+  (({a, b, r...}) ->
+    eq 1, a
+    deepEqual r, {c: 3, d: 44, e: 55}
+  ) {obj2..., d: 44, e: 55}
+
+  obj = {a: 1, b: 2, c: {d: 3, e: 4, f: {g: 5}}}
+  obj4 = {a: 10, obj.c...}
+  eq obj4.a, 10
+  eq obj4.d, 3
+  eq obj4.f.g, 5
+  deepEqual obj4.f, obj.c.f
+
+  # Should not trigger implicit call, e.g. rest ... => rest(...)
+  (({
+    a
+    b
+    r ...
+    }) ->
+    eq 1, a
+    deepEqual r, {c: 3, d: 44, e: 55}
+  ) {
+    obj2 ...
+    d: 44
+    e: 55
+  }
+
+  # Should not trigger implicit call, e.g. rest ... => rest(...)
+  obj4 = {
+    a: 10
+    obj.c ...
+  }
+  eq obj4.a, 10
+  eq obj4.d, 3
+  eq obj4.f.g, 5
+  deepEqual obj4.f, obj.c.f
+
+  obj5 = {obj..., ((k) -> {b: k})(99)...}
+  eq obj5.b, 99
+  deepEqual obj5.c, obj.c
+
+  # Should not trigger implicit call, e.g. rest ... => rest(...)
+  obj5 = {
+    obj ...
+    ((k) -> {b: k})(99) ...
+  }
+  eq obj5.b, 99
+  deepEqual obj5.c, obj.c
+
+  fn = -> {c: {d: 33, e: 44, f: {g: 55}}}
+  obj6 = {obj..., fn()...}
+  eq obj6.c.d, 33
+  deepEqual obj6.c, {d: 33, e: 44, f: {g: 55}}
+
+  obj7 = {obj..., fn()..., {c: {d: 55, e: 66, f: {77}}}...}
+  eq obj7.c.d, 55
+  deepEqual obj6.c, {d: 33, e: 44, f: {g: 55}}
+
+  # Should not trigger implicit call, e.g. rest ... => rest(...)
+  obj7 = {
+    obj ...
+    fn() ...
+    {c: {d: 55, e: 66, f: {77}}} ...
+  }
+  eq obj7.c.d, 55
+  deepEqual obj6.c, {d: 33, e: 44, f: {g: 55}}
+
+  obj =
+    a:
+      b:
+        c:
+          d:
+            e: {}
+  obj9 = {a:1, obj.a.b.c..., g:3}
+  deepEqual obj9.d, {e: {}}
+
+  a = "a"
+  c = "c"
+  obj9 = {a:1, obj[a].b[c]..., g:3}
+  deepEqual obj9.d, {e: {}}
+
+  obj9 = {a:1, obj.a["b"].c["d"]..., g:3}
+  deepEqual obj9["e"], {}
+
+test "#4673: complex destructured object spread variables", ->
+  b = c: 1
+  {{a...}...} = b
+  eq a.c, 1
+
+  d = {}
+  {d.e...} = f: 1
+  eq d.e.f, 1
+
+  {{g}...} = g: 1
+  eq g, 1
+
+test "rest element destructuring in function definition", ->
+  obj = {a: 1, b: 2, c: 3, d: 4, e: 5}
+
+  (({a, b, r...}) ->
+    eq 1, a
+    eq 2, b,
+    deepEqual r, {c: 3, d: 4, e: 5}
+  ) obj
+
+  (({a: p, b, r...}, q) ->
+    eq p, 1
+    eq q, 9
+    deepEqual r, {c: 3, d: 4, e: 5}
+  ) {a:1, b:2, c:3, d:4, e:5}, 9
+
+  # Should not trigger implicit call, e.g. rest ... => rest(...)
+  (({
+      a: p
+      b
+      r ...
+    }, q) ->
+    eq p, 1
+    eq q, 9
+    deepEqual r, {c: 3, d: 4, e: 5}
+  ) {a:1, b:2, c:3, d:4, e:5}, 9
+
+  a1={}; b1={}; c1={}; d1={}
+  obj1 = {
+    a: a1
+    b: {
+      'c': {
+        d: {
+          b1
+          e: c1
+          f: d1
+        }
+      }
+    }
+    b2: {b1, c1}
+  }
+
+  (({a: w, b: {c: {d: {b1: bb, r1...}}}, r2...}) ->
+    eq a1, w
+    eq bb, b1
+    eq r2.b, undefined
+    deepEqual r1, {e: c1, f: d1}
+    deepEqual r2.b2, {b1, c1}
+  ) obj1
+
+  b = 3
+  f = ({a, b...}) ->
+  f {}
+  eq 3, b
+
+  (({a, r...} = {}) ->
+    eq a, undefined
+    deepEqual r, {}
+  )()
+
+  (({a, r...} = {}) ->
+    eq a, 1
+    deepEqual r, {b: 2, c: 3}
+  ) {a: 1, b: 2, c: 3}
+
+  f = ({a, r...} = {}) -> [a, r]
+  deepEqual [undefined, {}], f()
+  deepEqual [1, {b: 2}], f {a: 1, b: 2}
+  deepEqual [1, {}], f {a: 1}
+
+  f = ({a, r...} = {a: 1, b: 2}) -> [a, r]
+  deepEqual [1, {b:2}], f()
+  deepEqual [2, {}], f {a:2}
+  deepEqual [3, {c:5}], f {a:3, c:5}
+
+  f = ({ a: aa = 0, b: bb = 0 }) -> [aa, bb]
+  deepEqual [0, 0], f {}
+  deepEqual [0, 42], f {b:42}
+  deepEqual [42, 0], f {a:42}
+  deepEqual [42, 43], f {a:42, b:43}
+
+test "#4673: complex destructured object spread variables", ->
+  f = ({{a...}...}) ->
+    a
+  eq f(c: 1).c, 1
+
+  g = ({@y...}) ->
+    eq @y.b, 1
+  g b: 1

test/objects.coffee

@@ -453,8 +453,7 @@ test 'inline implicit object literals within multiline implicit object literals'
   eq 0, x.b
   eq 0, x.a.aa
 
-test "object keys with interpolations", ->
-  # Simple cases.
+test "object keys with interpolations: simple cases", ->
   a = 'a'
   obj = "#{a}": yes
   eq obj.a, yes
@@ -465,7 +464,7 @@ test "object keys with interpolations", ->
   obj = {"#{5}"}
   eq obj[5], '5' # Note that the value is a string, just like the key.
 
-  # Commas in implicit object.
+test "object keys with interpolations: commas in implicit object", ->
   obj = "#{'a'}": 1, b: 2
   deepEqual obj, {a: 1, b: 2}
   obj = a: 1, "#{'b'}": 2
@@ -473,7 +472,7 @@ test "object keys with interpolations", ->
   obj = "#{'a'}": 1, "#{'b'}": 2
   deepEqual obj, {a: 1, b: 2}
 
-  # Commas in explicit object.
+test "object keys with interpolations: commas in explicit object", ->
   obj = {"#{'a'}": 1, b: 2}
   deepEqual obj, {a: 1, b: 2}
   obj = {a: 1, "#{'b'}": 2}
@@ -481,7 +480,7 @@ test "object keys with interpolations", ->
   obj = {"#{'a'}": 1, "#{'b'}": 2}
   deepEqual obj, {a: 1, b: 2}
 
-  # Commas after key with interpolation.
+test "object keys with interpolations: commas after key with interpolation", ->
   obj = {"#{'a'}": yes,}
   eq obj.a, yes
   obj = {
@@ -504,17 +503,17 @@ test "object keys with interpolations", ->
     "#{'c'}": 3, "#{'d'}": 4,
   deepEqual obj, {a: 1, b: 2, c: 3, d: 4}
 
-  # Key with interpolation mixed with `@prop`.
+test "object keys with interpolations: key with interpolation mixed with `@prop`", ->
   deepEqual (-> {@a, "#{'b'}": 2}).call(a: 1), {a: 1, b: 2}
 
-  # Evaluate only once.
+test "object keys with interpolations: evaluate only once", ->
   count = 0
-  b = -> count++; 'b'
-  obj = {"#{b()}"}
-  eq obj.b, 'b'
+  a = -> count++; 'a'
+  obj = {"#{a()}"}
+  eq obj.a, 'a'
   eq count, 1
 
-  # Evaluation order.
+test "object keys with interpolations: evaluation order", ->
   arr = []
   obj =
     a: arr.push 1
@@ -527,13 +526,13 @@ test "object keys with interpolations", ->
   arrayEq arr, [1..7]
   deepEqual obj, {a: 1, b: 2, c: 3, d: 4, e: 5, f: 6, g: 7}
 
-  # Object starting with dynamic key.
+test "object keys with interpolations: object starting with dynamic key", ->
   obj =
     "#{'a'}": 1
     b: 2
   deepEqual obj, {a: 1, b: 2}
 
-  # Comments in implicit object.
+test "object keys with interpolations: comments in implicit object", ->
   obj =
     ### leading comment ###
     "#{'a'}": 1
@@ -564,7 +563,7 @@ test "object keys with interpolations", ->
   }
   deepEqual obj, {a: 1, b: 2, c: 3, d: 4, e: 5}
 
-  # A more complicated case.
+test "object keys with interpolations: more complicated case", ->
   obj = {
     "#{'interpolated'}":
       """
@@ -582,6 +581,212 @@ test "#4324: Shorthand after interpolated key", ->
   eq 1, obj[1]
   eq 2, obj.a
 
+test "computed property keys: simple cases", ->
+  a = 'a'
+  obj = [a]: yes
+  eq obj.a, yes
+  obj = {[a]: yes}
+  eq obj.a, yes
+  obj = {[a]}
+  eq obj.a, 'a'
+  obj = {[5]}
+  eq obj[5], 5
+  obj = {['5']}
+  eq obj['5'], '5'
+
+test "computed property keys: commas in implicit object", ->
+  obj = ['a']: 1, b: 2
+  deepEqual obj, {a: 1, b: 2}
+  obj = a: 1, ['b']: 2
+  deepEqual obj, {a: 1, b: 2}
+  obj = ['a']: 1, ['b']: 2
+  deepEqual obj, {a: 1, b: 2}
+
+test "computed property keys: commas in explicit object", ->
+  obj = {['a']: 1, b: 2}
+  deepEqual obj, {a: 1, b: 2}
+  obj = {a: 1, ['b']: 2}
+  deepEqual obj, {a: 1, b: 2}
+  obj = {['a']: 1, ['b']: 2}
+  deepEqual obj, {a: 1, b: 2}
+
+test "computed property keys: commas after key with interpolation", ->
+  obj = {['a']: yes,}
+  eq obj.a, yes
+  obj = {
+    ['a']: 1,
+    ['b']: 2,
+    ### herecomment ###
+    ['c']: 3,
+  }
+  deepEqual obj, {a: 1, b: 2, c: 3}
+  obj =
+    ['a']: 1,
+    ['b']: 2,
+    ### herecomment ###
+    ['c']: 3,
+  deepEqual obj, {a: 1, b: 2, c: 3}
+  obj =
+    ['a']: 1,
+    ['b']: 2,
+    ### herecomment ###
+    ['c']: 3, ['d']: 4,
+  deepEqual obj, {a: 1, b: 2, c: 3, d: 4}
+
+test "computed property keys: key with interpolation mixed with `@prop`", ->
+  deepEqual (-> {@a, ['b']: 2}).call(a: 1), {a: 1, b: 2}
+
+test "computed property keys: evaluate only once", ->
+  count = 0
+  a = -> count++; 'a'
+  obj = {[a()]}
+  eq obj.a, 'a'
+  eq count, 1
+
+test "computed property keys: evaluation order", ->
+  arr = []
+  obj =
+    a: arr.push 1
+    b: arr.push 2
+    ['c']: arr.push 3
+    ['d']: arr.push 4
+    e: arr.push 5
+    ['f']: arr.push 6
+    g: arr.push 7
+  arrayEq arr, [1..7]
+  deepEqual obj, {a: 1, b: 2, c: 3, d: 4, e: 5, f: 6, g: 7}
+
+test "computed property keys: object starting with dynamic key", ->
+  obj =
+    ['a']: 1
+    b: 2
+  deepEqual obj, {a: 1, b: 2}
+
+test "computed property keys: comments in implicit object", ->
+  obj =
+    ### leading comment ###
+    ['a']: 1
+
+    ### middle ###
+
+    ['b']: 2
+    # regular comment
+    'c': 3
+    ### foo ###
+    d: 4
+    ['e']: 5
+  deepEqual obj, {a: 1, b: 2, c: 3, d: 4, e: 5}
+
+  obj = {
+    ### leading comment ###
+    ['a']: 1
+
+    ### middle ###
+
+    ['b']: 2
+    # regular comment
+    'c': 3
+    ### foo ###
+    d: 4
+    ['e']: 5
+  }
+  deepEqual obj, {a: 1, b: 2, c: 3, d: 4, e: 5}
+
+test "computed property keys: more complicated case", ->
+  obj = {
+    ['interpolated']:
+       ['nested']:
+         123: 456
+  }
+  deepEqual obj,
+    interpolated:
+      nested:
+        123: 456
+
+test "computed property keys: empty array as key", ->
+  o1 = { [[]] }
+  deepEqual o1, { [[]]: [] }
+  arrayEq o1[[]], []
+  o2 = { [[]]: 1 }
+  deepEqual o2, { [[]]: 1 }
+  eq o2[[]], 1
+  o3 = [[]]: 1
+  deepEqual o3, { [[]]: 1 }
+  deepEqual o3, { [[]]: 1 }
+  eq o3[[]], 1
+  o4 = a: 1, [[]]: 2
+  deepEqual o4, { a: 1, [[]]: 2 }
+  eq o4.a, 1,
+  eq o4[[]], 2
+  o5 = { a: 1, [[]]: 2 }
+  deepEqual o5, { a: 1, [[]]: 2 }
+  eq o5.a, 1,
+  eq o5[[]], 2
+
+test "computed property keys: shorthand after computed property key", ->
+  a = 2
+  obj = {[1]: 1, a}
+  eq 1, obj[1]
+  eq 2, obj.a
+
+test "computed property keys: shorthand computed property key", ->
+  a = 'b'
+  o = {[a]}
+  p = {a}
+  r = {['a']}
+  eq o.b, 'b'
+  eq p.a, o.b
+  eq r.a, 'a'
+
+  foo = -> "a"
+  obj = { [foo()] }
+  eq obj.a, 'a'
+
+test "computed property keys: arrays", ->
+  b = 'b'
+  f = (c) -> "#{c}1"
+  obj =
+    ['a']: [1, 2, 3]
+    [b]: [4, 5, 6]
+    [f(b)]: [7, 8, 9]
+  arrayEq obj.a, [1, 2, 3]
+  arrayEq obj.b, [4, 5, 6]
+  arrayEq obj.b1, [7, 8, 9]
+
+test "computed property keys: examples from developer.mozilla.org (Object initializer)", ->
+  i = 0
+  obj =
+    ['foo' + ++i]: i
+    ['foo' + ++i]: i
+    ['foo' + ++i]: i
+  eq obj.foo1, 1
+  eq obj.foo2, 2
+  eq obj.foo3, 3
+
+  param = 'size'
+  config =
+    [param]: 12,
+    ['mobile' + param.charAt(0).toUpperCase() + param.slice(1)]: 4
+  deepEqual config, {size: 12,  mobileSize: 4}
+
+test "computed property keys: [Symbol.iterator]", ->
+  obj =
+    [Symbol.iterator]: ->
+      yield "hello"
+      yield "world"
+  arrayEq [obj...], ['hello', 'world']
+
+test "computed property keys: Class property", ->
+  increment_method = "increment"
+  decrement_method = "decrement"
+  class Obs
+    constructor: (@count) ->
+    [increment_method]: -> @count += 1
+    [decrement_method]: -> @count -= 1
+  ob = new Obs 2
+  eq ob.increment(), 3
+  eq ob.decrement(), 2
+
 test "#1263: Braceless object return", ->
   fn = ->
     return
@@ -652,20 +857,22 @@ test "#4544: Postfix conditionals in first line of implicit object literals", ->
 test "#4579: Postfix for/while/until in first line of implicit object literals", ->
   two =
     foo:
-      bar: x for x in [1, 2, 3]
+      bar1: x for x in [1, 2, 3]
+      bar2: x + y for x, y in [1, 2, 3]
       baz: 1337
-  arrayEq [1, 2, 3], two.foo.bar
+  arrayEq [1, 2, 3], two.foo.bar1
+  arrayEq [1, 3, 5], two.foo.bar2
   eq 1337, two.foo.baz
 
   f = (x) -> x
 
   three =
     foo: f
-      # Uncomment when #4580 is fixed
-      # bar: x + y for x, y of a: 'b', c: 'd'
-      bar: x + 'c' for x of a: 1, b: 2
+      bar1: x + y for x, y of a: 'b', c: 'd'
+      bar2: x + 'c' for x of a: 1, b: 2
       baz: 1337
-  arrayEq ['ac', 'bc'], three.foo.bar
+  arrayEq ['ab', 'cd'], three.foo.bar1
+  arrayEq ['ac', 'bc'], three.foo.bar2
   eq 1337, three.foo.baz
 
   four =
@@ -696,4 +903,3 @@ test "#4579: Postfix for/while/until in first line of implicit object literals",
       baz: 1337
   arrayEq [4, 3, 2, 1, 0], six.foo.bar
   eq 1337, six.foo.baz
-

test/operators.coffee

@@ -305,24 +305,6 @@ test "#2508: Existential access of the prototype", ->
   eq NonExistent?::nothing, undefined
   ok Object?::toString
 
-test "power operator", ->
-  eq 27, 3 ** 3
-
-test "power operator has higher precedence than other maths operators", ->
-  eq 55, 1 + 3 ** 3 * 2
-  eq -4, -2 ** 2
-  eq false, !2 ** 2
-  eq 0, (!2) ** 2
-  eq -2, ~1 ** 5
-
-test "power operator is right associative", ->
-  eq 2, 2 ** 1 ** 3
-
-test "power operator compound assignment", ->
-  a = 2
-  a **= 3
-  eq 8, a
-
 test "floor division operator", ->
   eq 2, 7 // 3
   eq -3, -7 // 3

test/ranges.coffee

@@ -116,3 +116,129 @@ test "#1012 slices with arguments object", ->
 
 test "#1409: creating large ranges outside of a function body", ->
   CoffeeScript.eval '[0..100]'
+
+test "#2047: Infinite loop possible when `for` loop with `range` uses variables", ->
+  up = 1
+  down = -1
+  a = 1
+  b = 5
+
+  testRange = (arg) ->
+    [from, to, step, expectedResult] = arg
+    r = (x for x in [from..to] by step)
+    arrayEq r, expectedResult
+
+  testData = [
+    [1, 5, 1, [1..5]]
+    [1, 5, -1, []]
+    [1, 5, up, [1..5]]
+    [1, 5, down, []]
+
+    [a, 5, 1, [1..5]]
+    [a, 5, -1, []]
+    [a, 5, up, [1..5]]
+    [a, 5, down, []]
+
+    [1, b, 1, [1..5]]
+    [1, b, -1, []]
+    [1, b, up, [1..5]]
+    [1, b, down, []]
+
+    [a, b, 1, [1..5]]
+    [a, b, -1, []]
+    [a, b, up, [1..5]]
+    [a, b, down, []]
+
+    [5, 1, 1, []]
+    [5, 1, -1, [5..1]]
+    [5, 1, up, []]
+    [5, 1, down,  [5..1]]
+
+    [5, a, 1, []]
+    [5, a, -1, [5..1]]
+    [5, a, up, []]
+    [5, a, down, [5..1]]
+
+    [b, 1, 1, []]
+    [b, 1, -1, [5..1]]
+    [b, 1, up, []]
+    [b, 1, down, [5..1]]
+
+    [b, a, 1, []]
+    [b, a, -1, [5..1]]
+    [b, a, up, []]
+    [b, a, down, [5..1]]
+  ]
+
+  testRange d for d in testData
+
+test "#2047: from, to and step as variables", ->
+  up = 1
+  down = -1
+  a = 1
+  b = 5
+
+  r = (x for x in [a..b] by up)
+  arrayEq r, [1..5]
+
+  r = (x for x in [a..b] by down)
+  arrayEq r, []
+
+  r = (x for x in [b..a] by up)
+  arrayEq r, []
+
+  r = (x for x in [b..a] by down)
+  arrayEq r, [5..1]
+
+  a = 1
+  b = -1
+  step = 0
+  r = (x for x in [b..a] by step)
+  arrayEq r, []
+
+test "#4884: Range not declaring var for the 'i'", ->
+  'use strict'
+  [0..21].forEach (idx) ->
+    idx + 1
+
+  eq global.i, undefined
+
+test "#4889: `for` loop unexpected behavior", ->
+  n = 1
+  result = []
+  for i in [0..n]
+    result.push i
+    for j in [(i+1)..n]
+      result.push j
+
+  arrayEq result, [0,1,1,2,1]
+
+test "#4889: `for` loop unexpected behavior with `by 1` on second loop", ->
+  n = 1
+  result = []
+  for i in [0..n]
+    result.push i
+    for j in [(i+1)..n] by 1
+      result.push j
+
+  arrayEq result, [0,1,1]
+
+test "countdown example from docs", ->
+  countdown = (num for num in [10..1])
+  arrayEq countdown, [10,9,8,7,6,5,4,3,2,1]
+
+test "counting up when the range goes down returns an empty array", ->
+  countdown = (num for num in [10..1] by 1)
+  arrayEq countdown, []
+
+test "counting down when the range goes up returns an empty array", ->
+  countup = (num for num in [1..10] by -1)
+  arrayEq countup, []
+
+test "counting down by too much returns just the first value", ->
+  countdown = (num for num in [10..1] by -100)
+  arrayEq countdown, [10]
+
+test "counting up by too much returns just the first value", ->
+  countup = (num for num in [1..10] by 100)
+  arrayEq countup, [1]

test/regex.coffee

@@ -313,3 +313,16 @@ test "#4248: Unicode code point escapes", ->
   """
     /a\\udab3\\uddef/;
   """
+
+test "#4811, heregex comments with ///", ->
+  eqJS """
+    ///
+      a | # comment with ///
+      b   # /// 'heregex' in comment will be consumed
+    ///
+  """,
+  """
+   // comment with ///
+   // /// 'heregex' in comment will be consumed
+   /a|b/;
+  """

test/regex_dotall.coffee

@@ -0,0 +1,7 @@
+# Regex “dotall” flag, or `s`, is only supported in Node 9+, so put tests for
+# the feature in their own file. The feature detection in `Cakefile` that
+# causes this test to load is adapted from
+# https://github.com/tc39/proposal-regexp-dotall-flag#proposed-solution.
+
+test "dotall flag", ->
+  doesNotThrow -> /a.b/s.test 'a\nb'

test/repl.coffee

@@ -77,6 +77,14 @@ testRepl "empty command evaluates to undefined", (input, output) ->
   input.emitLine ''
   eq 'undefined', output.lastWrite()
 
+testRepl "#4763: comment evaluates to undefined", (input, output) ->
+  input.emitLine '# comment'
+  eq 'undefined', output.lastWrite()
+
+testRepl "#4763: multiple comments evaluate to undefined", (input, output) ->
+  input.emitLine '### a ### ### b ### # c'
+  eq 'undefined', output.lastWrite()
+
 testRepl "ctrl-v toggles multiline prompt", (input, output) ->
   input.emit 'keypress', null, ctrlV
   eq '------> ', output.lastWrite(0)
@@ -116,7 +124,7 @@ testRepl "keeps running after runtime error", (input, output) ->
   eq 'undefined', output.lastWrite()
 
 testRepl "#4604: wraps an async function", (input, output) ->
-  return unless global.supportsAsync
+  return unless try new Function 'async () => {}' # Feature detect support for async functions.
   input.emitLine 'await new Promise (resolve) -> setTimeout (-> resolve 33), 10'
   setTimeout ->
     eq '33', output.lastWrite()

test/slicing_and_splicing.coffee

@@ -165,3 +165,9 @@ test "#2953: methods on endpoints in assignment from array splice literal", ->
   delete Number.prototype.same
 
   arrayEq [0, 5, 9], list
+
+test "#1726: `Op` expression in property access causes unexpected results", ->
+  a = [0..2]
+  arrayEq a, a[(!1 in a)..]
+  arrayEq a, a[!1 in a..]
+  arrayEq a[(!1 in a)..], a[(!1 in a)..]