Merge pull request jashkenas#3002 from Nami-Doc/issue3001

Disallowed `for own in`

Author: jashkenas

lib/coffee-script/nodes.js

@@ -1837,6 +1837,7 @@ 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
     @returns = false
 
   children: ['body', 'source', 'guard', 'step']

src/nodes.coffee

@@ -81,4 +81,7 @@ test "#2846: while with empty body", ->
   CoffeeScript.compile 'while 1 then', {sourceMap: true}
 
 test "#2944: implicit call with a regex argument", ->
-  CoffeeScript.compile 'o[key] /regex/'
+  CoffeeScript.compile 'o[key] /regex/'
+
+test "#3001: `own` shouldn't be allowed in a `for`-`in` loop", ->
+  cantCompile "a for own b in c"

test/compilation.coffee

@@ -473,7 +473,7 @@ test "#1910: loop index should be mutable within a loop iteration and immutable
 
   arr = ([v, v + 1] for v in [0..5])
   iterations = 0
-  for own [v0, v1], k in arr when v0
+  for [v0, v1], k in arr when v0
     k += 3
     ++iterations
   eq 6, k