--- /dev/null
+'use strict';
+var redefine = require('../internals/redefine');
+var anObject = require('../internals/an-object');
+var fails = require('../internals/fails');
+var flags = require('../internals/regexp-flags');
+
+var TO_STRING = 'toString';
+var RegExpPrototype = RegExp.prototype;
+var nativeToString = RegExpPrototype[TO_STRING];
+
+var NOT_GENERIC = fails(function () { return nativeToString.call({ source: 'a', flags: 'b' }) != '/a/b'; });
+// FF44- RegExp#toString has a wrong name
+var INCORRECT_NAME = nativeToString.name != TO_STRING;
+
+// `RegExp.prototype.toString` method
+// https://tc39.es/ecma262/#sec-regexp.prototype.tostring
+if (NOT_GENERIC || INCORRECT_NAME) {
+ redefine(RegExp.prototype, TO_STRING, function toString() {
+ var R = anObject(this);
+ var p = String(R.source);
+ var rf = R.flags;
+ var f = String(rf === undefined && R instanceof RegExp && !('flags' in RegExpPrototype) ? flags.call(R) : rf);
+ return '/' + p + '/' + f;
+ }, { unsafe: true });
+}