From 9fb0d43934e9947ba009e131fed19773e0b037b5 Mon Sep 17 00:00:00 2001
From: Luke Wagner <luke@mozilla.com>
Date: Tue, 27 Mar 2012 14:48:10 -0700
Subject: [PATCH] Bug 736742 - Fix decompiler precedence for destructuring
 assignment with comma-expression (r=jorendorff)

--HG--
extra : rebase_source : d38dc6e2eec3a90e5bf1d86862da4734d374e6e2
---
 js/src/jit-test/tests/basic/testLet.js | 10 ++++++++++
 js/src/jsopcode.cpp                    |  9 +++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/js/src/jit-test/tests/basic/testLet.js b/js/src/jit-test/tests/basic/testLet.js
index d617259f323e..2dd0d4178c8d 100644
--- a/js/src/jit-test/tests/basic/testLet.js
+++ b/js/src/jit-test/tests/basic/testLet.js
@@ -73,6 +73,8 @@ test('return let (x = x + 1, [] = x, [[, , ]] = x, y = x) y;');
 test('return let ([{a: x}] = x, [, {b: y}] = x) let (x = x + 1, y = y + 2) x + y;', [{a:"p"},{b:"p"}], "p1p2");
 test('return let ([] = []) x;');
 test('return let ([] = [x]) x;');
+test('return let ([a] = (1, [x])) a;');
+test('return let ([a] = (1, x, 1, x)) a;', ['ponies']);
 test('return let ([x] = [x]) x;');
 test('return let ([[a, [b, c]]] = [[x, []]]) a;');
 test('return let ([x, y] = [x, x + 1]) x + y;', 1, 3);
@@ -129,6 +131,8 @@ test('let (x = x + 1, [] = x, [[, , ]] = x, y = x) {return y;}');
 test('let ([{a: x}] = x, [, {b: y}] = x) {let (x = x + 1, y = y + 2) {return x + y;}}', [{a:"p"},{b:"p"}], "p1p2");
 test('let ([] = []) {return x;}');
 test('let ([] = [x]) {return x;}');
+test('let ([a] = (1, [x])) {return a;}');
+test('let ([a] = (1, x, 1, x)) {return a;}', ['ponies']);
 test('let ([x] = [x]) {return x;}');
 test('let ([[a, [b, c]]] = [[x, []]]) {return a;}');
 test('let ([x, y] = [x, x + 1]) {return x + y;}', 1, 3);
@@ -174,6 +178,8 @@ test('var [{a: X}] = x, [, {b: y}] = x;var X = X + 1, y = y + 2;return X + y;',
 test('var [x] = [x];return x;');
 test('var [[a, [b, c]]] = [[x, []]];return a;');
 test('var [y] = [x];return y;');
+test('var [a] = (1, [x]);return a;');
+test('var [a] = (1, x, 1, x);return a;', ['ponies']);
 test('var [x, y] = [x, x + 1];return x + y;', 1, 3);
 test('var [x, y, z] = [x, x + 1, x + 2];return x + y + z;', 1, 6);
 test('var [[x]] = [[x]];return x;');
@@ -213,6 +219,8 @@ test('if (x) {let [{a: X}] = x, [, {b: Y}] = x;var XX = X + 1, YY = Y + 2;return
 test('if (x) {let [[a, [b, c]]] = [[x, []]];return a;}');
 test('if (x) {let [X] = [x];return X;}');
 test('if (x) {let [y] = [x];return y;}');
+test('if (x) {let [a] = (1, [x]);return a;}');
+test('if (x) {let [a] = (1, x, 1, x);return a;}', ['ponies']);
 test('if (x) {let [X, y] = [x, x + 1];return X + y;}', 1, 3);
 test('if (x) {let [X, y, z] = [x, x + 1, x + 2];return X + y + z;}', 1, 6);
 test('if (x) {let [[X]] = [[x]];return X;}');
@@ -279,6 +287,8 @@ test('for (let y;;) {let y;return x;}');
 test('for (let a = x;;) {let c = x, d = x;return c;}');
 test('for (let [a, b] = x;;) {let c = x, d = x;return c;}');
 test('for (let [] = [[]] = {};;) {return x;}');
+test('for (let [a] = (1, [x]);;) {return a;}');
+test('for (let [a] = (1, x, 1, x);;) {return a;}', ['ponies']);
 isError('for (let x = 1, x = 2;;) {}');
 isError('for (let [x, y] = a, {a:x} = b;;) {}');
 isError('for (let [x, y, x] = a;;) {}');
diff --git a/js/src/jsopcode.cpp b/js/src/jsopcode.cpp
index 9b5b0c65af60..59347bfd675d 100644
--- a/js/src/jsopcode.cpp
+++ b/js/src/jsopcode.cpp
@@ -4095,8 +4095,13 @@ Decompile(SprintStack *ss, jsbytecode *pc, int nb)
                         if (!pc)
                             return NULL;
 
-                        lval = POP_STR();  /* Pop the decompiler result. */
-                        rval = POP_STR();  /* Pop the initializer expression. */
+                        /* Left-hand side never needs parens. */
+                        JS_ASSERT(js_CodeSpec[JSOP_POP].prec <= 3);
+                        lval = PopStr(ss, JSOP_POP);
+
+                        /* Make sure comma-expression on rhs gets parens. */
+                        JS_ASSERT(js_CodeSpec[JSOP_SETNAME].prec > js_CodeSpec[JSOP_POP].prec);
+                        rval = PopStr(ss, JSOP_SETNAME);
 
                         if (strcmp(rval, forelem_cookie) == 0) {
                             todo = Sprint(&ss->sprinter, ss_format,