Fix #3935: Implicit calls + obj key interpolation

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

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