From 6e420ff28d9b3e76ac2c3598bf3797540ef8a1d3 Mon Sep 17 00:00:00 2001
From: Tero Parviainen <tero@teropa.info>
Date: Tue, 1 Apr 2014 06:53:35 +0300
Subject: [PATCH] fix($parse): mark constant unary minus expressions as
 constant

Previously, constant numbers with a unary minus sign were not treated as constants. This fix corrects
this behaviour, and may provide a small performance boost for certain applications, due to constant
watches being automatically unregistered after their first listener call.

Closes #6932
---
 src/ng/parse.js      | 6 +++++-
 test/ng/parseSpec.js | 1 +
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/ng/parse.js b/src/ng/parse.js
index 885dc50afab9..50da14fa0770 100644
--- a/src/ng/parse.js
+++ b/src/ng/parse.js
@@ -393,7 +393,11 @@ var Parser = function (lexer, $filter, options) {
   this.options = options;
 };
 
-Parser.ZERO = function () { return 0; };
+Parser.ZERO = extend(function () {
+  return 0;
+}, {
+  constant: true
+});
 
 Parser.prototype = {
   constructor: Parser,
diff --git a/test/ng/parseSpec.js b/test/ng/parseSpec.js
index 6a6bb4a1182d..a76fa86b6de4 100644
--- a/test/ng/parseSpec.js
+++ b/test/ng/parseSpec.js
@@ -1031,6 +1031,7 @@ describe('parser', function() {
 
           it('should mark complex expressions involving constant values as constant', inject(function($parse) {
             expect($parse('!true').constant).toBe(true);
+            expect($parse('-42').constant).toBe(true);
             expect($parse('1 - 1').constant).toBe(true);
             expect($parse('"foo" + "bar"').constant).toBe(true);
             expect($parse('5 != null').constant).toBe(true);