From ca4ea7649d94c4185666b06fa5b5b3928834f1db Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas <jashkenas@gmail.com>
Date: Sun, 25 Apr 2010 11:22:15 -0400
Subject: [PATCH] Throwing an error when pattern matching has a non-identifier
 on the left-hand side.

---
 lib/nodes.js     | 3 +++
 src/nodes.coffee | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/lib/nodes.js b/lib/nodes.js
index 4400601f..e7ff45df 100644
--- a/lib/nodes.js
+++ b/lib/nodes.js
@@ -943,6 +943,9 @@
           obj = _c[0];
           idx = _c[1];
         }
+        if (!(obj instanceof ValueNode || obj instanceof SplatNode)) {
+          throw new Error('pattern matching must use only identifiers on the left-hand side.');
+        }
         is_string = idx.value && idx.value.match(IS_STRING);
         access_class = is_string || this.variable.is_array() ? IndexNode : AccessorNode;
         if (obj instanceof SplatNode && !splat) {
diff --git a/src/nodes.coffee b/src/nodes.coffee
index f8c938a2..500c6ec4 100644
--- a/src/nodes.coffee
+++ b/src/nodes.coffee
@@ -692,6 +692,8 @@ exports.AssignNode: class AssignNode extends BaseNode
     for obj, i in @variable.base.objects
       idx: i
       [obj, idx]: [obj.value, obj.variable.base] if @variable.is_object()
+      if not (obj instanceof ValueNode or obj instanceof SplatNode)
+        throw new Error 'pattern matching must use only identifiers on the left-hand side.'
       is_string: idx.value and idx.value.match IS_STRING
       access_class: if is_string or @variable.is_array() then IndexNode else AccessorNode
       if obj instanceof SplatNode and not splat