2.2.1 (#4885)

* 2.2.1 changelog

* Bump version to 2.2.1 and update output

docs/v2/annotated-source/nodes.html

@@ -2947,7 +2947,11 @@ needed to iterate over the values in the range. Used by comprehensions.</p>
     idx      = del o, <span class="hljs-string">'index'</span>
     idxName  = del o, <span class="hljs-string">'name'</span>
     namedIndex = idxName <span class="hljs-keyword">and</span> idxName <span class="hljs-keyword">isnt</span> idx
-    varPart  = <span class="hljs-string">"<span class="hljs-subst">#{idx}</span> = <span class="hljs-subst">#{@fromC}</span>"</span>
+    varPart  =
+      <span class="hljs-keyword">if</span> known <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> namedIndex
+        <span class="hljs-string">"var <span class="hljs-subst">#{idx}</span> = <span class="hljs-subst">#{@fromC}</span>"</span>
+      <span class="hljs-keyword">else</span>
+        <span class="hljs-string">"<span class="hljs-subst">#{idx}</span> = <span class="hljs-subst">#{@fromC}</span>"</span>
     varPart += <span class="hljs-string">", <span class="hljs-subst">#{@toC}</span>"</span> <span class="hljs-keyword">if</span> @toC <span class="hljs-keyword">isnt</span> @toVar
     varPart += <span class="hljs-string">", <span class="hljs-subst">#{@step}</span>"</span> <span class="hljs-keyword">if</span> @step <span class="hljs-keyword">isnt</span> @stepVar
     [lt, gt] = [<span class="hljs-string">"<span class="hljs-subst">#{idx}</span> &lt;<span class="hljs-subst">#{@equals}</span>"</span>, <span class="hljs-string">"<span class="hljs-subst">#{idx}</span> &gt;<span class="hljs-subst">#{@equals}</span>"</span>]</pre></div></div>
@@ -4955,8 +4959,8 @@ Examples: [a, b, c…, d, e, f…], [a, b, …, c, d, …], [a, b, …, c, d, e
             
             <div class="content"><div class='highlight'><pre>      objects[splatsAndExpans.sort()[<span class="hljs-number">1</span>]].error <span class="hljs-string">"multiple splats/expansions are disallowed in an assignment"</span>
 
-    isSplat = splats.length
-    isExpans = expans.length
+    isSplat = splats?.length &gt; <span class="hljs-number">0</span>
+    isExpans = expans?.length &gt; <span class="hljs-number">0</span>
     isObject = @variable.isObject()
     isArray = @variable.isArray()
 
@@ -5101,7 +5105,7 @@ Examples: [a, b, {c, r…}, d], [a, …, {b, r…}, c, d]</p>
 
             </div>
             
-            <div class="content"><div class='highlight'><pre><span class="hljs-function">    <span class="hljs-title">loopObjects</span> = <span class="hljs-params">(objs, vvarTxt)</span> =&gt;</span>
+            <div class="content"><div class='highlight'><pre><span class="hljs-function">    <span class="hljs-title">loopObjects</span> = <span class="hljs-params">(objs, vvar, vvarTxt)</span> =&gt;</span>
       objSpreads = hasObjSpreads objs
       <span class="hljs-keyword">for</span> obj, i <span class="hljs-keyword">in</span> objs</pre></div></div>
             
@@ -5182,16 +5186,16 @@ Examples: [a, b, {c, r…}, d], [a, …, {b, r…}, c, d]</p>
 
             </div>
             
-            <div class="content"><div class='highlight'><pre><span class="hljs-function">    <span class="hljs-title">assignObjects</span> = <span class="hljs-params">(objs, vvarTxt)</span> =&gt;</span>
+            <div class="content"><div class='highlight'><pre><span class="hljs-function">    <span class="hljs-title">assignObjects</span> = <span class="hljs-params">(objs, vvar, vvarTxt)</span> =&gt;</span>
       vvar = <span class="hljs-keyword">new</span> Value <span class="hljs-keyword">new</span> Arr(objs, <span class="hljs-literal">yes</span>)
       vval = <span class="hljs-keyword">if</span> vvarTxt <span class="hljs-keyword">instanceof</span> Value <span class="hljs-keyword">then</span> vvarTxt <span class="hljs-keyword">else</span> <span class="hljs-keyword">new</span> Value <span class="hljs-keyword">new</span> Literal(vvarTxt)
       assigns.push <span class="hljs-keyword">new</span> Assign(vvar, vval, <span class="hljs-literal">null</span>, param: @param, subpattern: <span class="hljs-literal">yes</span>).compileToFragments o, LEVEL_LIST
 <span class="hljs-function">
-    <span class="hljs-title">processObjects</span> = <span class="hljs-params">(objs, vvarTxt)</span> -&gt;</span>
+    <span class="hljs-title">processObjects</span> = <span class="hljs-params">(objs, vvar, vvarTxt)</span> -&gt;</span>
       <span class="hljs-keyword">if</span> complexObjects objs
-        loopObjects objs, vvarTxt
+        loopObjects objs, vvar, vvarTxt
       <span class="hljs-keyword">else</span>
-        assignObjects objs, vvarTxt</pre></div></div>
+        assignObjects objs, vvar, vvarTxt</pre></div></div>
             
         </li>
         
@@ -5220,7 +5224,7 @@ b) <code>Expansion</code>
       expIdx = splatsAndExpans[<span class="hljs-number">0</span>]
       leftObjs = objects.slice <span class="hljs-number">0</span>, expIdx + (<span class="hljs-keyword">if</span> isSplat <span class="hljs-keyword">then</span> <span class="hljs-number">1</span> <span class="hljs-keyword">else</span> <span class="hljs-number">0</span>)
       rightObjs = objects.slice expIdx + <span class="hljs-number">1</span>
-      processObjects leftObjs, vvarText <span class="hljs-keyword">if</span> leftObjs.length <span class="hljs-keyword">isnt</span> <span class="hljs-number">0</span>
+      processObjects leftObjs, vvar, vvarText <span class="hljs-keyword">if</span> leftObjs.length <span class="hljs-keyword">isnt</span> <span class="hljs-number">0</span>
       <span class="hljs-keyword">if</span> rightObjs.length <span class="hljs-keyword">isnt</span> <span class="hljs-number">0</span></pre></div></div>
             
         </li>
@@ -5243,7 +5247,7 @@ b) <code>Expansion</code>
           restVar = refExp
           refExp = o.scope.freeVariable <span class="hljs-string">'ref'</span>
           assigns.push [@makeCode(refExp + <span class="hljs-string">' = '</span>), restVar.compileToFragments(o, LEVEL_LIST)...]
-        processObjects rightObjs, refExp
+        processObjects rightObjs, vvar, refExp
     <span class="hljs-keyword">else</span></pre></div></div>
             
         </li>
@@ -5259,7 +5263,7 @@ b) <code>Expansion</code>
 
             </div>
             
-            <div class="content"><div class='highlight'><pre>      processObjects objects, vvarText
+            <div class="content"><div class='highlight'><pre>      processObjects objects, vvar, vvarText
     assigns.push vvar <span class="hljs-keyword">unless</span> top <span class="hljs-keyword">or</span> @subpattern
     fragments = @joinFragmentArrays assigns, <span class="hljs-string">', '</span>
     <span class="hljs-keyword">if</span> o.level &lt; LEVEL_LIST <span class="hljs-keyword">then</span> fragments <span class="hljs-keyword">else</span> @wrapInParentheses fragments</pre></div></div>

docs/v2/index.html

@@ -646,7 +646,7 @@ div.CodeMirror-cursor {
       <section id="overview">
         <p><strong>CoffeeScript is a little language that compiles into JavaScript.</strong> Underneath that awkward Java-esque patina, JavaScript has always had a gorgeous heart. CoffeeScript is an attempt to expose the good parts of JavaScript in a simple way.</p>
 <p>The golden rule of CoffeeScript is: <em>“It’s just JavaScript.”</em> The code compiles one-to-one into the equivalent JS, and there is no interpretation at runtime. You can use any existing JavaScript library seamlessly from CoffeeScript (and vice-versa). The compiled output is readable, pretty-printed, and tends to run as fast or faster than the equivalent handwritten JavaScript.</p>
-<p><strong>Latest Version:</strong> <a href="https://github.com/jashkenas/coffeescript/tarball/2.2.0">2.2.0</a></p>
+<p><strong>Latest Version:</strong> <a href="https://github.com/jashkenas/coffeescript/tarball/2.2.1">2.2.1</a></p>
 <blockquote class="uneditable-code-block"><pre><code class="language-bash"><span class="comment"># Install locally for a project:</span>
 npm install --save-dev coffeescript
 
@@ -4790,7 +4790,7 @@ The CoffeeScript logo is available in SVG for use in presentations.</li>
         </section>
         <section id="annotated-source">
           <h2>Annotated Source</h2>
-<p>You can browse the CoffeeScript 2.2.0 source in readable, annotated form <a href="annotated-source/">here</a>. You can also jump directly to a particular source file:</p>
+<p>You can browse the CoffeeScript 2.2.1 source in readable, annotated form <a href="annotated-source/">here</a>. You can also jump directly to a particular source file:</p>
 <ul>
 <li><a href="annotated-source/grammar.html">Grammar Rules — src/grammar</a></li>
 <li><a href="annotated-source/lexer.html">Lexing Tokens — src/lexer</a></li>
@@ -5467,6 +5467,14 @@ x = <span class="number">2</span> + <span class="number">2</span>
       </section>
       <section id="changelog">
         <h2>Changelog</h2>
+<div class="anchor" id="2.2.1"></div>
+<h2 class="header">
+  <a href="https://github.com/jashkenas/coffeescript/compare/2.1.0...2.2.1">2.2.1</a>
+  <span class="timestamp"> &mdash; <time datetime="2018-02-06">February 6, 2018</time></span>
+</h2><ul>
+<li>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.</li>
+<li>Bugfix for regression in 2.2.0 where in certain cases a range iterator variable was declared in the global scope.</li>
+</ul>
 <div class="anchor" id="2.2.0"></div>
 <h2 class="header">
   <a href="https://github.com/jashkenas/coffeescript/compare/2.1.1...2.2.0">2.2.0</a>

docs/v2/test.html

@@ -1573,6 +1573,46 @@ test "#4673: complex destructured object spread variables", ->
   {{g}...} = g: 1
   eq g, 1
 
+test "#4878: Compile error when using destructuring with a splat or expansion in an array", ->
+  arr = ['a', 'b', 'c', 'd']
+
+  f1 = (list) ->
+    [first, ..., last] = list
+
+  f2 = (list) ->
+    [first..., last] = list
+
+  f3 = (list) ->
+    ([first, ...] = list); first
+
+  f4 = (list) ->
+    ([first, ...rest] = list); rest
+
+  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']]
+
 </script>
 <script type="text/x-coffeescript" class="test" id="async">
 # Functions that contain the `await` keyword will compile into async functions,
@@ -16173,6 +16213,13 @@ test "#2047: from, to and step as variables", ->
   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
+
 </script>
 <script type="text/x-coffeescript" class="test" id="regexps">
 # Regular Expression Literals

documentation/sections/changelog.md

@@ -1,5 +1,11 @@
 ## Changelog
 
+```
+releaseHeader('2018-02-06', '2.2.1', '2.1.0')
+```
+*   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')
 ```

lib/coffeescript/browser.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.2.0
+// Generated by CoffeeScript 2.2.1
 (function() {
   // This **Browser** compatibility layer extends core CoffeeScript functions
   // to make things work smoothly when compiling code directly in the browser.

lib/coffeescript/cake.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.2.0
+// Generated by CoffeeScript 2.2.1
 (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 2.2.0
+// Generated by CoffeeScript 2.2.1
 (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

lib/coffeescript/command.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.2.0
+// Generated by CoffeeScript 2.2.1
 (function() {
   // The `coffee` utility. Handles command-line compilation of CoffeeScript
   // into various forms: saved into `.js` files or printed to stdout

lib/coffeescript/grammar.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.2.0
+// Generated by CoffeeScript 2.2.1
 (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

lib/coffeescript/helpers.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.2.0
+// Generated by CoffeeScript 2.2.1
 (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

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.2.0
+// Generated by CoffeeScript 2.2.1
 (function() {
   // Node.js Implementation
   var CoffeeScript, ext, fs, helpers, i, len, path, ref, universalCompile, vm,

lib/coffeescript/lexer.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.2.0
+// Generated by CoffeeScript 2.2.1
 (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,

lib/coffeescript/nodes.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.2.0
+// Generated by CoffeeScript 2.2.1
 (function() {
   // `nodes.coffee` contains all of the node classes for the syntax tree. Most
   // nodes are created as the result of actions in the [grammar](grammar.html),
@@ -2043,7 +2043,7 @@
         idx = del(o, 'index');
         idxName = del(o, 'name');
         namedIndex = idxName && idxName !== idx;
-        varPart = `${idx} = ${this.fromC}`;
+        varPart = known && !namedIndex ? `var ${idx} = ${this.fromC}` : `${idx} = ${this.fromC}`;
         if (this.toC !== this.toVar) {
           varPart += `, ${this.toC}`;
         }
@@ -3575,8 +3575,8 @@ this.toVar}`, upperBound = `${this.fromVar} >= ${idx} && ${gt} ${this.toVar}`, `
           // Sort 'splatsAndExpans' so we can show error at first disallowed token.
           objects[splatsAndExpans.sort()[1]].error("multiple splats/expansions are disallowed in an assignment");
         }
-        isSplat = splats.length;
-        isExpans = expans.length;
+        isSplat = (splats != null ? splats.length : void 0) > 0;
+        isExpans = (expans != null ? expans.length : void 0) > 0;
         isObject = this.variable.isObject();
         isArray = this.variable.isArray();
         vvar = value.compileToFragments(o, LEVEL_LIST);
@@ -3648,7 +3648,7 @@ this.toVar}`, upperBound = `${this.fromVar} >= ${idx} && ${gt} ${this.toVar}`, `
         };
         // "Complex" `objects` are processed in a loop.
         // Examples: [a, b, {c, r...}, d], [a, ..., {b, r...}, c, d]
-        loopObjects = (objs, vvarTxt) => {
+        loopObjects = (objs, vvar, vvarTxt) => {
           var acc, idx, j, len1, message, objSpreads, results, vval;
           objSpreads = hasObjSpreads(objs);
           results = [];
@@ -3707,7 +3707,7 @@ this.toVar}`, upperBound = `${this.fromVar} >= ${idx} && ${gt} ${this.toVar}`, `
           return results;
         };
         // "Simple" `objects` can be split and compiled to arrays, [a, b, c] = arr, [a, b, c...] = arr
-        assignObjects = (objs, vvarTxt) => {
+        assignObjects = (objs, vvar, vvarTxt) => {
           var vval;
           vvar = new Value(new Arr(objs, true));
           vval = vvarTxt instanceof Value ? vvarTxt : new Value(new Literal(vvarTxt));
@@ -3716,11 +3716,11 @@ this.toVar}`, upperBound = `${this.fromVar} >= ${idx} && ${gt} ${this.toVar}`, `
             subpattern: true
           }).compileToFragments(o, LEVEL_LIST));
         };
-        processObjects = function(objs, vvarTxt) {
+        processObjects = function(objs, vvar, vvarTxt) {
           if (complexObjects(objs)) {
-            return loopObjects(objs, vvarTxt);
+            return loopObjects(objs, vvar, vvarTxt);
           } else {
-            return assignObjects(objs, vvarTxt);
+            return assignObjects(objs, vvar, vvarTxt);
           }
         };
         // In case there is `Splat` or `Expansion` in `objects`,
@@ -3739,7 +3739,7 @@ this.toVar}`, upperBound = `${this.fromVar} >= ${idx} && ${gt} ${this.toVar}`, `
           leftObjs = objects.slice(0, expIdx + (isSplat ? 1 : 0));
           rightObjs = objects.slice(expIdx + 1);
           if (leftObjs.length !== 0) {
-            processObjects(leftObjs, vvarText);
+            processObjects(leftObjs, vvar, vvarText);
           }
           if (rightObjs.length !== 0) {
             // Slice or splice `objects`.
@@ -3756,11 +3756,11 @@ this.toVar}`, upperBound = `${this.fromVar} >= ${idx} && ${gt} ${this.toVar}`, `
               refExp = o.scope.freeVariable('ref');
               assigns.push([this.makeCode(refExp + ' = '), ...restVar.compileToFragments(o, LEVEL_LIST)]);
             }
-            processObjects(rightObjs, refExp);
+            processObjects(rightObjs, vvar, refExp);
           }
         } else {
           // There is no `Splat` or `Expansion` in `objects`.
-          processObjects(objects, vvarText);
+          processObjects(objects, vvar, vvarText);
         }
         if (!(top || this.subpattern)) {
           assigns.push(vvar);

lib/coffeescript/optparse.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.2.0
+// Generated by CoffeeScript 2.2.1
 (function() {
   var LONG_FLAG, MULTI_FLAG, OPTIONAL, OptionParser, SHORT_FLAG, buildRule, buildRules, normalizeArguments, repeat,
     splice = [].splice;

lib/coffeescript/register.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.2.0
+// Generated by CoffeeScript 2.2.1
 (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 2.2.0
+// Generated by CoffeeScript 2.2.1
 (function() {
   var CoffeeScript, addHistory, addMultilineHandler, fs, getCommandId, merge, nodeREPL, path, replDefaults, runInContext, sawSIGINT, transpile, updateSyntaxError, vm;
 

lib/coffeescript/rewriter.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.2.0
+// Generated by CoffeeScript 2.2.1
 (function() {
   // The CoffeeScript language has a good deal of optional syntax, implicit syntax,
   // and shorthand syntax. This can greatly complicate a grammar and bloat

lib/coffeescript/scope.js

@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 2.2.0
+// Generated by CoffeeScript 2.2.1
 (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 2.2.0
+// Generated by CoffeeScript 2.2.1
 (function() {
   // Source maps allow JavaScript runtimes to match running JavaScript back to
   // the original source code that corresponds to it. This can be minified

package.json

@@ -8,7 +8,7 @@
     "compiler"
   ],
   "author": "Jeremy Ashkenas",
-  "version": "2.2.0",
+  "version": "2.2.1",
   "license": "MIT",
   "engines": {
     "node": ">=6"

src/nodes.coffee

@@ -1353,7 +1353,11 @@ 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}"]
@@ -2408,8 +2412,8 @@ exports.Assign = class Assign extends Base
       # Sort 'splatsAndExpans' so we can show error at first disallowed token.
       objects[splatsAndExpans.sort()[1]].error "multiple splats/expansions are disallowed in an assignment"
 
-    isSplat = splats.length
-    isExpans = expans.length
+    isSplat = splats?.length > 0
+    isExpans = expans?.length > 0
     isObject = @variable.isObject()
     isArray = @variable.isArray()
 
@@ -2458,7 +2462,7 @@ exports.Assign = class Assign extends Base
 
     # "Complex" `objects` are processed in a loop.
     # Examples: [a, b, {c, r...}, d], [a, ..., {b, r...}, c, d]
-    loopObjects = (objs, vvarTxt) =>
+    loopObjects = (objs, vvar, vvarTxt) =>
       objSpreads = hasObjSpreads objs
       for obj, i in objs
         # `Elision` can be skipped.
@@ -2488,16 +2492,16 @@ exports.Assign = class Assign extends Base
         assigns.push new Assign(vvar, vval, null, param: @param, subpattern: yes).compileToFragments o, LEVEL_LIST
 
     # "Simple" `objects` can be split and compiled to arrays, [a, b, c] = arr, [a, b, c...] = arr
-    assignObjects = (objs, vvarTxt) =>
+    assignObjects = (objs, vvar, vvarTxt) =>
       vvar = new Value new Arr(objs, yes)
       vval = if vvarTxt instanceof Value then vvarTxt else new Value new Literal(vvarTxt)
       assigns.push new Assign(vvar, vval, null, param: @param, subpattern: yes).compileToFragments o, LEVEL_LIST
 
-    processObjects = (objs, vvarTxt) ->
+    processObjects = (objs, vvar, vvarTxt) ->
       if complexObjects objs
-        loopObjects objs, vvarTxt
+        loopObjects objs, vvar, vvarTxt
       else
-        assignObjects objs, vvarTxt
+        assignObjects objs, vvar, vvarTxt
 
     # In case there is `Splat` or `Expansion` in `objects`,
     # we can split array in two simple subarrays.
@@ -2514,7 +2518,7 @@ exports.Assign = class Assign extends Base
       expIdx = splatsAndExpans[0]
       leftObjs = objects.slice 0, expIdx + (if isSplat then 1 else 0)
       rightObjs = objects.slice expIdx + 1
-      processObjects leftObjs, vvarText if leftObjs.length isnt 0
+      processObjects leftObjs, vvar, vvarText if leftObjs.length isnt 0
       if rightObjs.length isnt 0
         # Slice or splice `objects`.
         refExp = switch
@@ -2524,10 +2528,10 @@ exports.Assign = class Assign extends Base
           restVar = refExp
           refExp = o.scope.freeVariable 'ref'
           assigns.push [@makeCode(refExp + ' = '), restVar.compileToFragments(o, LEVEL_LIST)...]
-        processObjects rightObjs, refExp
+        processObjects rightObjs, vvar, refExp
     else
       # There is no `Splat` or `Expansion` in `objects`.
-      processObjects objects, vvarText
+      processObjects objects, vvar, vvarText
     assigns.push vvar unless top or @subpattern
     fragments = @joinFragmentArrays assigns, ', '
     if o.level < LEVEL_LIST then fragments else @wrapInParentheses fragments

test/assignment.coffee

@@ -945,3 +945,43 @@ test "#4673: complex destructured object spread variables", ->
 
   {{g}...} = g: 1
   eq g, 1
+
+test "#4878: Compile error when using destructuring with a splat or expansion in an array", ->
+  arr = ['a', 'b', 'c', 'd']
+
+  f1 = (list) ->
+    [first, ..., last] = list
+
+  f2 = (list) ->
+    [first..., last] = list
+
+  f3 = (list) ->
+    ([first, ...] = list); first
+
+  f4 = (list) ->
+    ([first, ...rest] = list); rest
+
+  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/ranges.coffee

@@ -195,3 +195,10 @@ test "#2047: from, to and step as variables", ->
   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