Class block scoping tests

Class bindings are mutable and lexically scoped, with TDZ semantics.
They may not overlap with var bindings in the same scope. This patch
adds tests for those properties.

R=adamk
BUG=v8:3305
LOG=N

Review URL: https://codereview.chromium.org/1254003004

Cr-Commit-Position: refs/heads/master@{#29856}

test/mjsunit/harmony/block-scope-class.js

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Test for conflicting variable bindings.
+
+// Flags: --harmony-sloppy
+
+function AssertEqualsStrictAndSloppy(value, code) {
+  assertEquals(value, eval("(function() {" + code + "})()"));
+  assertEquals(value, eval("(function() { 'use strict'; " + code + "})()"));
+  assertEquals(value, eval("(function() { var x = 0; {" + code + "} })()"));
+  assertEquals(value, eval("(function() { 'use strict'; var x = 0; {"
+                           + code + "} })()"));
+}
+
+function AssertThrowsStrictAndSloppy(code, error) {
+  assertThrows("(function() {" + code + "})()", error);
+  assertThrows("(function() { 'use strict'; " + code + "})()", error);
+  assertThrows("(function() { var x = 0; { " + code + "} })()", error);
+  assertThrows("(function() { 'use strict'; var x = 0; {" + code + "} })()",
+               error);
+}
+
+(function TestClassTDZ() {
+  AssertEqualsStrictAndSloppy(
+      "x", "function f() { return x; }; class x { }; return f().name;");
+  AssertEqualsStrictAndSloppy
+      ("x", "class x { }; function f() { return x; }; return f().name;");
+  AssertEqualsStrictAndSloppy(
+      "x", "class x { }; var result = f().name; " +
+      "function f() { return x; }; return result;");
+  AssertThrowsStrictAndSloppy(
+      "function f() { return x; }; f(); class x { };", ReferenceError);
+  AssertThrowsStrictAndSloppy(
+      "f(); function f() { return x; }; class x { };", ReferenceError);
+  AssertThrowsStrictAndSloppy(
+      "f(); class x { }; function f() { return x; };", ReferenceError);
+  AssertThrowsStrictAndSloppy(
+      "var x = 1; { f(); class x { }; function f() { return x; }; }",
+      ReferenceError);
+  AssertThrowsStrictAndSloppy("x = 3; class x { };", ReferenceError)
+})();
+
+(function TestClassNameConflict() {
+  AssertThrowsStrictAndSloppy("class x { }; var x;", SyntaxError);
+  AssertThrowsStrictAndSloppy("var x; class x { };", SyntaxError);
+  AssertThrowsStrictAndSloppy("class x { }; function x() { };", SyntaxError);
+  AssertThrowsStrictAndSloppy("function x() { }; class x { };", SyntaxError);
+  AssertThrowsStrictAndSloppy("class x { }; for (var x = 0; false;) { };",
+                              SyntaxError);
+  AssertThrowsStrictAndSloppy("for (var x = 0; false;) { }; class x { };",
+                              SyntaxError);
+})();
+
+(function TestClassMutableBinding() {
+  AssertEqualsStrictAndSloppy(
+      "x3", "class x { }; var y = x.name; x = 3; return y + x;")
+})();