From 32aef1a031b0386f2968a8b2636822cd417d730a Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Wed, 25 Feb 2015 18:01:40 -0800
Subject: [PATCH] do not report error on non-initialized const bindings in
 for-in\for-of statements

---
 src/compiler/checker.ts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 7918d393c0b..7094f9e7ea8 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -11498,7 +11498,8 @@ module ts {
                     if (isBindingPattern(node.name) && !isBindingPattern(node.parent)) {
                         return grammarErrorOnNode(node, Diagnostics.A_destructuring_declaration_must_have_an_initializer);
                     }
-                    if (isConst(node)) {
+                    // const declarations should not be initialized in for-in for-of statements
+                    if (isConst(node) && node.parent.parent.kind !== SyntaxKind.ForInStatement && node.parent.parent.kind !== SyntaxKind.ForOfStatement) {
                         return grammarErrorOnNode(node, Diagnostics.const_declarations_must_be_initialized);
                     }
                 }