Fixes #3053 - error for mismatched own/for-in without an index.

Author: jashkenas

lib/coffee-script/nodes.js

@@ -1846,7 +1846,7 @@ exports.For = class For extends While
     @pattern = @name instanceof Value
     @index.error 'indexes do not apply to range loops' if @range and @index
     @name.error 'cannot pattern match over range loops' if @range and @pattern
-    @index.error 'cannot use own with for-in' if @own and not @object
+    @name.error 'cannot use own with for-in' if @own and not @object
     @returns = false
 
   children: ['body', 'source', 'guard', 'step']