From 10616560da2f0cfd3749587836aaa927cb057eec Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Thu, 14 Apr 2016 11:32:33 -0700
Subject: [PATCH] Fix the incorrectly assigned arrow expression trailing
 comments Fixes #8041

---
 src/compiler/printer.ts                                    | 7 +++++--
 src/compiler/transformers/es6.ts                           | 1 +
 .../reference/disallowLineTerminatorBeforeArrow.js         | 4 +---
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/compiler/printer.ts b/src/compiler/printer.ts
index e26a36233b7..451e002d5bf 100644
--- a/src/compiler/printer.ts
+++ b/src/compiler/printer.ts
@@ -1505,8 +1505,11 @@ const _super = (function (geti, seti) {
                 const endingLine = writer.getLine();
                 emitLexicalEnvironment(endLexicalEnvironment(), /*newLine*/ startingLine !== endingLine);
 
-                const range = collapseRangeToEnd(body.statements);
-                emitLeadingComments(range, getLeadingComments(range));
+                // Do not emit leading comments if the body belongs to arrow expression
+                if (!body.original || isBlock(body.original)) {
+                    const range = collapseRangeToEnd(body.statements);
+                    emitLeadingComments(range, getLeadingComments(range));
+                }
                 decreaseIndent();
             }
 
diff --git a/src/compiler/transformers/es6.ts b/src/compiler/transformers/es6.ts
index 7b769889dca..0d0ab884cca 100644
--- a/src/compiler/transformers/es6.ts
+++ b/src/compiler/transformers/es6.ts
@@ -1271,6 +1271,7 @@ namespace ts {
                 setNodeEmitFlags(block, NodeEmitFlags.SingleLine);
             }
 
+            setOriginalNode(block, node.body);
             return block;
         }
 
diff --git a/tests/baselines/reference/disallowLineTerminatorBeforeArrow.js b/tests/baselines/reference/disallowLineTerminatorBeforeArrow.js
index 55fba8115e0..1044146ccd0 100644
--- a/tests/baselines/reference/disallowLineTerminatorBeforeArrow.js
+++ b/tests/baselines/reference/disallowLineTerminatorBeforeArrow.js
@@ -110,9 +110,7 @@ var f8 = function (x, y, z) {
 var f9 = function (a) { return a; };
 var f10 = function (a) { return a; };
 var f11 = function (a) { return a; };
-var f12 = function (a) {
-    return a;
-};
+var f12 = function (a) { return a; };
 // Should be valid.
 var f11 = function (a) { return a; };
 // Should be valid.