From 8f28c95b041ba8cf46e3da93973a95552ae83248 Mon Sep 17 00:00:00 2001
From: Ivo Gabe de Wolff <ivogabe@ivogabe.nl>
Date: Mon, 5 Jan 2015 20:30:38 +0100
Subject: [PATCH] Emit parens when an argument is a comma operator

Example:
foo`A${ 1 }B${ 2, 3 }C`;
---
 src/compiler/emitter.ts | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 602e4ccc12c..f3e4cefa919 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -2079,7 +2079,9 @@ module ts {
                     // Now we emit the expressions
                     forEach(node.templateSpans, templateSpan => {
                         write(", ");
-                        emit(templateSpan.expression);
+                        var needsParens = templateSpan.expression.kind === SyntaxKind.BinaryExpression
+                            && (<BinaryExpression> templateSpan.expression).operator === SyntaxKind.CommaToken;
+                        emitParenthesized(templateSpan.expression, needsParens);
                     });
                     return;
                 }