Fix the incorrectly assigned arrow expression trailing comments

sheetalkamat · sheetalkamat · commit 10616560da2f · 2016-04-14T11:34:50.000-07:00
Fixes microsoft#8041
diff --git 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
@@ -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
@@ -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.

Original file line number	Diff line number	Diff line change
`@@ -1271,6 +1271,7 @@ namespace ts {`
`1271`	`1271`	`setNodeEmitFlags(block, NodeEmitFlags.SingleLine);`
`1272`	`1272`	`}`
`1273`	`1273`
	`1274`	`+ setOriginalNode(block, node.body);`
`1274`	`1275`	`return block;`
`1275`	`1276`	`}`
`1276`	`1277`