diff -r 000000000000 -r 6474c204b198 js/src/tests/js1_8_1/extensions/strict-warning.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/js1_8_1/extensions/strict-warning.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,32 @@
+// Turn on strict mode and warnings-as-errors mode.
+if (options().split().indexOf('strict') == -1)
+    options('strict');
+if (options().split().indexOf('werror') == -1)
+    options('werror');
+
+function expectSyntaxError(stmt) {
+    print(stmt);
+    var result = 'no error';
+    try {
+        Function(stmt);
+    } catch (exc) {
+        result = exc.constructor.name;
+    }
+    assertEq(result, 'SyntaxError');
+}
+
+function test(expr) {
+    // Without extra parentheses, expect an error.
+    expectSyntaxError('if (' + expr + ') {};');
+
+    // Extra parentheses silence the warning/error.
+    Function('if ((' + expr + ')) {};');
+}
+
+// Overparenthesized assignment in a condition should not be a strict error.
+test('a = 0');
+test('a = (f(), g)');
+test('a = b || c > d');
+expectSyntaxError('if (a == 0);');
+reportCompare('passed', 'passed', 'Overparenthesized assignment in a condition should not be a strict error.');
+