Make `String.prototype.{starts,ends}With` throw when passing a regular expression

src/harmony-string.js

-// Copyright 2013 the V8 project authors. All rights reserved.
+// Copyright 2014 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
 //       with the distribution.
@@ skipping 15 matching lines @@
 
 'use strict';
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $String = global.String;
 // var $Array = global.Array;
 
 // -------------------------------------------------------------------
 
-// ES6 draft 07-15-13, section 15.5.3.21
+// ES6 draft 01-20-14, section 21.1.3.13
 function StringRepeat(count) {
-  if (IS_NULL_OR_UNDEFINED(this) && !IS_UNDETECTABLE(this)) {
-    throw MakeTypeError("called_on_null_or_undefined",
-                        ["String.prototype.repeat"]);
-  }
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.repeat");
 
   var s = TO_STRING_INLINE(this);
   var n = ToInteger(count);
   if (n < 0 || !NUMBER_IS_FINITE(n)) {
     throw MakeRangeError("invalid_count_value", []);
   }
 
   var elements = new InternalArray(n);
   for (var i = 0; i < n; i++) {
     elements[i] = s;
   }
 
   return %StringBuilderConcat(elements, n, "");
 }
 
 
-// ES6 draft 07-15-13, section 15.5.3.22
+// ES6 draft 01-20-14, section 21.1.3.18
 function StringStartsWith(searchString /* position */) {  // length == 1
-  if (IS_NULL_OR_UNDEFINED(this) && !IS_UNDETECTABLE(this)) {
-    throw MakeTypeError("called_on_null_or_undefined",
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.startsWith");
+
+  var s = TO_STRING_INLINE(this);
+
+  if (IS_REGEXP(searchString)) {
+    throw MakeTypeError("first_argument_not_regexp",
                         ["String.prototype.startsWith"]);
   }
 
-  var s = TO_STRING_INLINE(this);
   var ss = TO_STRING_INLINE(searchString);
   var pos = 0;
   if (%_ArgumentsLength() > 1) {
     pos = %_Arguments(1);  // position
     pos = ToInteger(pos);
   }
 
   var s_len = s.length;
   var start = MathMin(MathMax(pos, 0), s_len);
   var ss_len = ss.length;
   if (ss_len + start > s_len) {
     return false;
   }
 
   return %StringIndexOf(s, ss, start) === start;
 }
 
 
-// ES6 draft 07-15-13, section 15.5.3.23
+// ES6 draft 01-20-14, section 21.1.3.7
 function StringEndsWith(searchString /* position */) {  // length == 1
-  if (IS_NULL_OR_UNDEFINED(this) && !IS_UNDETECTABLE(this)) {
-    throw MakeTypeError("called_on_null_or_undefined",
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.endsWith");
+
+  var s = TO_STRING_INLINE(this);
+
+  if (IS_REGEXP(searchString)) {
+    throw MakeTypeError("first_argument_not_regexp",
                         ["String.prototype.endsWith"]);
   }
 
-  var s = TO_STRING_INLINE(this);
   var ss = TO_STRING_INLINE(searchString);
   var s_len = s.length;
   var pos = s_len;
   if (%_ArgumentsLength() > 1) {
     var arg = %_Arguments(1);  // position
     if (!IS_UNDEFINED(arg)) {
       pos = ToInteger(arg);
     }
   }
 
   var end = MathMin(MathMax(pos, 0), s_len);
   var ss_len = ss.length;
   var start = end - ss_len;
   if (start < 0) {
     return false;
   }
 
   return %StringLastIndexOf(s, ss, start) === start;
 }
 
 
-// ES6 draft 07-15-13, section 15.5.3.24
+// ES6 draft 01-20-14, section 21.1.3.6
 function StringContains(searchString /* position */) {  // length == 1
-  if (IS_NULL_OR_UNDEFINED(this) && !IS_UNDETECTABLE(this)) {
-    throw MakeTypeError("called_on_null_or_undefined",
-                        ["String.prototype.contains"]);
-  }
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.contains");
 
   var s = TO_STRING_INLINE(this);
   var ss = TO_STRING_INLINE(searchString);
   var pos = 0;
   if (%_ArgumentsLength() > 1) {
     pos = %_Arguments(1);  // position
     pos = ToInteger(pos);
   }
 
   var s_len = s.length;
@@ skipping 15 matching lines @@
   // Set up the non-enumerable functions on the String prototype object.
   InstallFunctions($String.prototype, DONT_ENUM, $Array(
     "repeat", StringRepeat,
     "startsWith", StringStartsWith,
     "endsWith", StringEndsWith,
     "contains", StringContains
   ));
 }
 
 ExtendStringPrototype();