Dynamic import (#5169)

* dynamic import

* updated grammar

* specify callable

* DynamicImportCall

* Fix from code review

Co-Authored-By: helixbass <julian@helixbass.net>

* recompile

test/error_messages.coffee

@@ -1925,3 +1925,29 @@ test "`new.target` is only allowed meta property", ->
     -> new.something
        ^^^^^^^^^^^^^
   '''
+
+test "#4834: dynamic import requires exactly one argument", ->
+  assertErrorFormat '''
+    import()
+  ''', '''
+    [stdin]:1:1: error: import() requires exactly one argument
+    import()
+    ^^^^^^^^
+  '''
+
+  assertErrorFormat '''
+    import('x', {})
+  ''', '''
+    [stdin]:1:1: error: import() requires exactly one argument
+    import('x', {})
+    ^^^^^^^^^^^^^^^
+  '''
+
+test "#4834: dynamic import requires explicit call parentheses", ->
+  assertErrorFormat '''
+    promise = import 'foo'
+  ''', '''
+    [stdin]:1:23: error: unexpected end of input
+    promise = import 'foo'
+                          ^
+  '''

test/modules.coffee

@@ -920,3 +920,24 @@ test "#4874: backslash `export`", ->
       min
     } from 'underscore';
     """
+
+test "#4834: dynamic import", ->
+  eqJS """
+    import('module').then ->
+  """,
+  """
+    import('module').then(function() {});
+  """
+
+  eqJS """
+    foo = ->
+      bar = await import('bar')
+  """,
+  """
+    var foo;
+
+    foo = async function() {
+      var bar;
+      return bar = (await import('bar'));
+    };
+  """

test/object_rest_spread.coffee

@@ -418,3 +418,13 @@ test "#4673: complex destructured object spread variables", ->
   g = ({@y...}) ->
     eq @y.b, 1
   g b: 1
+
+test "#4834: dynamic import can technically be object spread", ->
+  eqJS """
+    x = {...import('module')}
+  """,
+  """
+    var x;
+
+    x = {...import('module')};
+  """