Fix #3935: Implicit calls + obj key interpolation

Allow implicit calls when the first key of an implicit object has interpolation.

lib/coffee-script/nodes.js

@@ -1311,7 +1311,7 @@
           indent += TAB;
         }
         if (prop instanceof Assign && prop.variable instanceof Value && prop.variable.hasProperties()) {
-          prop.variable.error('Invalid object key');
+          prop.variable.error('invalid object key');
         }
         if (prop instanceof Value && prop["this"]) {
           prop = new Assign(prop.properties[0].name, prop, 'object');

lib/coffee-script/rewriter.js

@@ -284,7 +284,7 @@
           startImplicitCall(i + 1);
           return forward(2);
         }
-        if (indexOf.call(IMPLICIT_FUNC, tag) >= 0 && this.indexOfTag(i + 1, 'INDENT', null, ':') > -1 && !this.findTagsBackwards(i, ['CLASS', 'EXTENDS', 'IF', 'CATCH', 'SWITCH', 'LEADING_WHEN', 'FOR', 'WHILE', 'UNTIL'])) {
+        if (indexOf.call(IMPLICIT_FUNC, tag) >= 0 && this.indexOfTag(i + 1, 'INDENT') > -1 && this.looksObjectish(i + 2) && !this.findTagsBackwards(i, ['CLASS', 'EXTENDS', 'IF', 'CATCH', 'SWITCH', 'LEADING_WHEN', 'FOR', 'WHILE', 'UNTIL'])) {
           startImplicitCall(i + 1);
           stack.push(['INDENT', i + 2]);
           return forward(3);

src/nodes.coffee

@@ -952,7 +952,7 @@ exports.Obj = class Obj extends Base
       indent = if prop instanceof Comment then '' else idt
       indent += TAB if hasDynamic and i < dynamicIndex
       if prop instanceof Assign and prop.variable instanceof Value and prop.variable.hasProperties()
-        prop.variable.error 'Invalid object key'
+        prop.variable.error 'invalid object key'
       if prop instanceof Value and prop.this
         prop = new Assign prop.properties[0].name, prop, 'object'
       if prop not instanceof Comment

src/rewriter.coffee

@@ -254,7 +254,7 @@ class exports.Rewriter
       # Furthermore don't allow this in literal arrays, as
       # that creates grammatical ambiguities.
       if tag in IMPLICIT_FUNC and
-         @indexOfTag(i + 1, 'INDENT', null, ':') > -1 and
+         @indexOfTag(i + 1, 'INDENT') > -1 and @looksObjectish(i + 2) and
          not @findTagsBackwards(i, ['CLASS', 'EXTENDS', 'IF', 'CATCH',
           'SWITCH', 'LEADING_WHEN', 'FOR', 'WHILE', 'UNTIL'])
         startImplicitCall i + 1

test/error_messages.coffee

@@ -751,3 +751,20 @@ test "unexpected object keys", ->
     {a: 1, [[]]: 2}
            ^
   '''
+
+test "invalid object keys", ->
+  assertErrorFormat '''
+    @a: 1
+  ''', '''
+    [stdin]:1:1: error: invalid object key
+    @a: 1
+    ^^
+  '''
+  assertErrorFormat '''
+    f
+      @a: 1
+  ''', '''
+    [stdin]:2:3: error: invalid object key
+      @a: 1
+      ^^
+  '''

test/function_invocation.coffee

@@ -695,3 +695,14 @@ test 'implicit invocation with implicit object literal', ->
     else
       "a": 1
   eq 2, obj.a
+
+  # #3935: Implicit call when the first key of an implicit object has interpolation.
+  a = 'a'
+  f
+    "#{a}": 1
+  obj =
+    if f
+      "#{a}": 2
+    else
+      "#{a}": 1
+  eq 2, obj.a