From 2344a80e6f73c7e1ebadf388a5f36fb657ec306f Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Sun, 11 Sep 2016 10:19:52 -0700
Subject: [PATCH] Handle const binding elements with initializers correctly

---
 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 4440eeaa3aa..fbbb38ac6a0 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -3117,7 +3117,8 @@ namespace ts {
         // pattern. Otherwise, it is the type any.
         function getTypeFromBindingElement(element: BindingElement, includePatternInType?: boolean, reportErrors?: boolean): Type {
             if (element.initializer) {
-                return getBaseTypeOfLiteralType(checkExpressionCached(element.initializer));
+                const exprType = checkExpressionCached(element.initializer);
+                return getCombinedNodeFlags(element) & NodeFlags.Const ? exprType : getBaseTypeOfLiteralType(exprType);
             }
             if (isBindingPattern(element.name)) {
                 return getTypeFromBindingPattern(<BindingPattern>element.name, includePatternInType, reportErrors);