Bug 1263139 - Apply ToString to non-standard flags argument of String.prototype.{match,search,replace}. r=till

js/src/builtin/String.js

@@ -44,7 +44,7 @@ function String_match(regexp) {
     var flags = undefined;
     if (arguments.length > 1) {
         if (IsMatchFlagsArgumentEnabled())
-            flags = arguments[1];
+            flags = ToString(arguments[1]);
         WarnOnceAboutFlagsArgument();
     } else {
         if (isPatternString && IsStringMatchOptimizable()) {
@@ -166,7 +166,7 @@ function String_replace(searchValue, replaceValue) {
     if (arguments.length > 2) {
         WarnOnceAboutFlagsArgument();
         if (IsMatchFlagsArgumentEnabled()) {
-            flags = arguments[2];
+            flags = ToString(arguments[2]);
             var rx = RegExpCreate(RegExpEscapeMetaChars(searchString), flags);
 
             return callContentFunction(GetMethod(rx, std_replace), rx, string, replaceValue);
@@ -257,7 +257,7 @@ function String_search(regexp) {
     var flags = undefined;
     if (arguments.length > 1) {
         if (IsMatchFlagsArgumentEnabled())
-            flags = arguments[1];
+            flags = ToString(arguments[1]);
         WarnOnceAboutFlagsArgument();
     } else {
         if (isPatternString && IsStringSearchOptimizable()) {

js/src/tests/ecma_6/extensions/String-match-flags.js

@@ -0,0 +1,29 @@
+var BUGNUMBER = 1263139;
+var summary = "String.prototype.match with non-string non-standard flags argument.";
+
+print(BUGNUMBER + ": " + summary);
+
+enableMatchFlagArgument();
+
+var called;
+var flags = {
+  toString() {
+    called = true;
+    return "";
+  }
+};
+
+called = false;
+"a".match("a", flags);
+assertEq(called, true);
+
+called = false;
+"a".search("a", flags);
+assertEq(called, true);
+
+called = false;
+"a".replace("a", "b", flags);
+assertEq(called, true);
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);