From 80224d2deccba39d4bd49b5953cb08012274fc0b Mon Sep 17 00:00:00 2001
From: Ron Buckton <rbuckton@microsoft.com>
Date: Mon, 16 May 2016 09:43:24 -0700
Subject: [PATCH] Fix issue with emit flag reset in param initializers.

---
 src/compiler/transformer.ts      | 7 ++++++-
 src/compiler/transformers/es6.ts | 2 +-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/compiler/transformer.ts b/src/compiler/transformer.ts
index 53a07872621..a18b8546db8 100644
--- a/src/compiler/transformer.ts
+++ b/src/compiler/transformer.ts
@@ -210,7 +210,12 @@ namespace ts {
          * Sets flags that control emit behavior of a node.
          */
         function setNodeEmitFlags<T extends Node>(node: T, flags: NodeEmitFlags) {
-            getEmitOptions(node, /*create*/ true).flags = flags;
+            const options = getEmitOptions(node, /*create*/ true);
+            if (flags & NodeEmitFlags.Merge) {
+                flags = options.flags | (flags & ~NodeEmitFlags.Merge);
+            }
+
+            options.flags = flags;
             return node;
         }
 
diff --git a/src/compiler/transformers/es6.ts b/src/compiler/transformers/es6.ts
index 4c4e65e7910..ef9f4f29d1d 100644
--- a/src/compiler/transformers/es6.ts
+++ b/src/compiler/transformers/es6.ts
@@ -959,7 +959,7 @@ namespace ts {
                         createStatement(
                             createAssignment(
                                 setNodeEmitFlags(getMutableClone(name), NodeEmitFlags.NoSourceMap),
-                                setNodeEmitFlags(visitNode(initializer, visitor, isExpression), NodeEmitFlags.NoSourceMap),
+                                setNodeEmitFlags(visitNode(initializer, visitor, isExpression), NodeEmitFlags.NoSourceMap | NodeEmitFlags.Merge),
                                 /*location*/ parameter
                             )
                         )