Fix #3306: trailing comma in a function call in the last line throws a syntax error (#4860)

* fix #3306

* added test

Author: zdenko

lib/coffeescript/rewriter.js

@@ -364,7 +364,8 @@ exports.Rewriter = class Rewriter
         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

src/rewriter.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);
+  '''