[es6] Handle conflicts for sloppy let

We have to call CheckConflictingVarDeclarations in case we have enabled
--harmony-sloppy

BUG=v8:4287
LOG=N
R=littledan@chromium.org, rossberg@chromium.org

Review URL: https://codereview.chromium.org/1226103002

Cr-Commit-Position: refs/heads/master@{#29578}

src/parser.cc

@@ -1062,6 +1062,8 @@ FunctionLiteral* Parser::DoParseProgram(ParseInfo* info) {
 
     if (ok && is_strict(language_mode())) {
       CheckStrictOctalLiteral(beg_pos, scanner()->location().end_pos, &ok);
+    }
+    if (ok && (is_strict(language_mode()) || allow_harmony_sloppy())) {
       CheckConflictingVarDeclarations(scope_, &ok);
     }
 
@@ -4141,6 +4143,8 @@ FunctionLiteral* Parser::ParseFunctionLiteral(
     if (is_strict(language_mode())) {
       CheckStrictOctalLiteral(scope->start_position(), scope->end_position(),
                               CHECK_OK);
+    }
+    if (is_strict(language_mode()) || allow_harmony_sloppy()) {
       CheckConflictingVarDeclarations(scope, CHECK_OK);
     }
   }

src/preparser.h

@@ -3770,6 +3770,8 @@ ParserBase<Traits>::ParseArrowFunctionLiteral(
     if (is_strict(language_mode())) {
       CheckStrictOctalLiteral(formal_parameters.scope->start_position(),
                               scanner()->location().end_pos, CHECK_OK);
+    }
+    if (is_strict(language_mode()) || allow_harmony_sloppy()) {
       this->CheckConflictingVarDeclarations(formal_parameters.scope, CHECK_OK);
     }
   }

test/mjsunit/harmony/block-conflicts-sloppy.js

+// Copyright 2011 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: --no-legacy-const --harmony-sloppy
+
+function CheckException(e) {
+  var string = e.toString();
+  assertTrue(string.indexOf("has already been declared") >= 0 ||
+             string.indexOf("redeclaration") >= 0);
+  return 'Conflict';
+}
+
+
+function TestGlobal(s,e) {
+  try {
+    return eval(s + e);
+  } catch (x) {
+    return CheckException(x);
+  }
+}
+
+
+function TestFunction(s,e) {
+  try {
+    return eval("(function(){" + s + " return " + e + "})")();
+  } catch (x) {
+    return CheckException(x);
+  }
+}
+
+
+function TestBlock(s,e) {
+  try {
+    return eval("(function(){ {" + s + "} return " + e + "})")();
+  } catch (x) {
+    return CheckException(x);
+  }
+}
+
+function TestAll(expected,s,opt_e) {
+  var e = "";
+  var msg = s;
+  if (opt_e) { e = opt_e; msg += opt_e; }
+  // TODO(littledan): https://code.google.com/p/v8/issues/detail?id=4288
+  // It is also not clear whether these tests makes sense in sloppy mode.
+  // TODO(littledan): Add tests using Realm.eval to ensure that global eval
+  // works as expected.
+  // assertEquals(expected === 'LocalConflict' ? 'NoConflict' : expected,
+  //     TestGlobal(s,e), "global:'" + msg + "'");
+  assertEquals(expected === 'LocalConflict' ? 'NoConflict' : expected,
+      TestFunction(s,e), "function:'" + msg + "'");
+  assertEquals(expected === 'LocalConflict' ? 'Conflict' : expected,
+      TestBlock(s,e), "block:'" + msg + "'");
+}
+
+
+function TestConflict(s) {
+  TestAll('Conflict', s);
+  // TODO(littledan): https://code.google.com/p/v8/issues/detail?id=4288
+  // It is also not clear whether these tests makes sense in sloppy mode.
+  // TestAll('Conflict', 'eval("' + s + '");');
+}
+
+function TestNoConflict(s) {
+  TestAll('NoConflict', s, "'NoConflict'");
+  // TODO(littledan): https://code.google.com/p/v8/issues/detail?id=4288
+  // TestAll('NoConflict', 'eval("' + s + '");', "'NoConflict'");
+}
+
+function TestLocalConflict(s) {
+  TestAll('LocalConflict', s, "'NoConflict'");
+  // TODO(littledan): https://code.google.com/p/v8/issues/detail?id=4288
+  // It is also not clear whether these tests makes sense in sloppy mode.
+  // TestAll('NoConflict', 'eval("' + s + '");', "'NoConflict'");
+}
+
+var letbinds = [ "let x;",
+                 "let x = 0;",
+                 "let x = undefined;",
+                 "let x = function() {};",
+                 "let x, y;",
+                 "let y, x;",
+                 "const x = 0;",
+                 "const x = undefined;",
+                 "const x = function() {};",
+                 "const x = 2, y = 3;",
+                 "const y = 4, x = 5;",
+                 ];
+var varbinds = [ "var x;",
+                 "var x = 0;",
+                 "var x = undefined;",
+                 "var x = function() {};",
+                 "var x, y;",
+                 "var y, x;",
+                 ];
+var funbind = "function x() {}";
+
+for (var l = 0; l < letbinds.length; ++l) {
+  // Test conflicting let/var bindings.
+  for (var v = 0; v < varbinds.length; ++v) {
+    // Same level.
+    TestConflict(letbinds[l] + varbinds[v]);
+    TestConflict(varbinds[v] + letbinds[l]);
+    // Different level.
+    TestConflict(letbinds[l] + '{' + varbinds[v] + '}');
+    TestConflict('{' + varbinds[v] +'}' + letbinds[l]);
+    TestNoConflict(varbinds[v] + '{' + letbinds[l] + '}');
+    TestNoConflict('{' + letbinds[l] + '}' + varbinds[v]);
+    // For loop.
+    TestConflict('for (' + letbinds[l] + '0;) {' + varbinds[v] + '}');
+    TestNoConflict('for (' + varbinds[v] + '0;) {' + letbinds[l] + '}');
+  }
+
+  // Test conflicting let/let bindings.
+  for (var k = 0; k < letbinds.length; ++k) {
+    // Same level.
+    TestConflict(letbinds[l] + letbinds[k]);
+    TestConflict(letbinds[k] + letbinds[l]);
+    // Different level.
+    TestNoConflict(letbinds[l] + '{ ' + letbinds[k] + '}');
+    TestNoConflict('{' + letbinds[k] +'} ' + letbinds[l]);
+    // For loop.
+    TestNoConflict('for (' + letbinds[l] + '0;) {' + letbinds[k] + '}');
+    TestNoConflict('for (' + letbinds[k] + '0;) {' + letbinds[l] + '}');
+  }
+
+  // Test conflicting function/let bindings.
+  // Same level.
+  TestConflict(letbinds[l] + funbind);
+  TestConflict(funbind + letbinds[l]);
+  // Different level.
+  TestNoConflict(letbinds[l] + '{' + funbind + '}');
+  TestNoConflict('{' + funbind + '}' + letbinds[l]);
+  TestNoConflict(funbind + '{' + letbinds[l] + '}');
+  TestNoConflict('{' + letbinds[l] + '}' + funbind);
+  // For loop.
+  TestNoConflict('for (' + letbinds[l] + '0;) {' + funbind + '}');
+
+  // Test conflicting parameter/let bindings.
+  TestConflict('(function(x) {' + letbinds[l] + '})();');
+}
+
+// Test conflicting function/var bindings.
+for (var v = 0; v < varbinds.length; ++v) {
+  // Same level.
+  TestLocalConflict(varbinds[v] + funbind);
+  TestLocalConflict(funbind + varbinds[v]);
+  // Different level.
+  TestLocalConflict(funbind + '{' + varbinds[v] + '}');
+  TestLocalConflict('{' + varbinds[v] +'}' + funbind);
+  TestNoConflict(varbinds[v] + '{' + funbind + '}');
+  TestNoConflict('{' + funbind + '}' + varbinds[v]);
+  // For loop.
+  TestNoConflict('for (' + varbinds[v] + '0;) {' + funbind + '}');
+}
+
+// Test conflicting catch/var bindings.
+for (var v = 0; v < varbinds.length; ++v) {
+  TestNoConflict('try {} catch(x) {' + varbinds[v] + '}');
+}
+
+// Test conflicting parameter/var bindings.
+for (var v = 0; v < varbinds.length; ++v) {
+  TestNoConflict('(function (x) {' + varbinds[v] + '})();');
+}
+
+// Test conflicting catch/function bindings.
+TestNoConflict('try {} catch(x) {' + funbind + '}');
+
+// Test conflicting parameter/function bindings.
+TestNoConflict('(function (x) {' + funbind + '})();');