Revert of [es6] Implement destructuring binding in try/catch (patchset #3...

Revert of [es6] Implement destructuring binding in try/catch (patchset #3 id:40001 of https://codereview.chromium.org/1417483014/ )

Reason for revert:
MSAN errors on arm64: http://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20arm64%20-%20sim%20-%20MSAN/builds/5123/

Original issue's description:
> [es6] Implement destructuring binding in try/catch
>
> The approach is to desugar
>
>   try { ... }
>   catch ({x, y}) { ... }
>
> into
>
>   try { ... }
>   catch (.catch) {
>     let x = .catch.x;
>     let y = .catch.y;
>     ...
>   }
>
> using the PatternRewriter's normal facilities. This has the side benefit
> of throwing the appropriate variable conflict errors for declarations
> made inside the catch block.
>
> No change is made to non-destructured cases, which will hopefully save
> us some work if https://github.com/tc39/ecma262/issues/150 is adopted
> in the spec.
>
> There's one big problem with this patch, which is a lack of PreParser
> support for the redeclaration errors. But it seems we're already lacking
> good PreParser support for such errors, so I'm not sure that should
> block this moving forward.
>
> BUG=v8:811
> LOG=y
>
> Committed: https://crrev.com/a316db995e6e4253664920652ed4e5a38b2caeba
> Cr-Commit-Position: refs/heads/master@{#31797}

TBR=rossberg@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:811

Review URL: https://codereview.chromium.org/1408063013

Cr-Commit-Position: refs/heads/master@{#31798}

src/ast-value-factory.h

@@ -255,7 +255,6 @@ class AstValue : public ZoneObject {
   F(dot_module, ".module")                      \
   F(dot_result, ".result")                      \
   F(dot_switch_tag, ".switch_tag")              \
-  F(dot_catch, ".catch")                        \
   F(empty, "")                                  \
   F(eval, "eval")                               \
   F(let, "let")                                 \

src/parser.cc

@@ -1073,8 +1073,7 @@ FunctionLiteral* Parser::DoParseProgram(ParseInfo* info) {
       // unchanged if the property already exists.
       InsertSloppyBlockFunctionVarBindings(scope, &ok);
     }
-    if (ok && (is_strict(language_mode()) || allow_harmony_sloppy() ||
-               allow_harmony_destructuring())) {
+    if (ok && (is_strict(language_mode()) || allow_harmony_sloppy())) {
       CheckConflictingVarDeclarations(scope_, &ok);
     }
 
@@ -3149,78 +3148,21 @@ TryStatement* Parser::ParseTryStatement(bool* ok) {
   Scope* catch_scope = NULL;
   Variable* catch_variable = NULL;
   Block* catch_block = NULL;
+  const AstRawString* name = NULL;
   if (tok == Token::CATCH) {
     Consume(Token::CATCH);
 
     Expect(Token::LPAREN, CHECK_OK);
     catch_scope = NewScope(scope_, CATCH_SCOPE);
     catch_scope->set_start_position(scanner()->location().beg_pos);
+    name = ParseIdentifier(kDontAllowRestrictedIdentifiers, CHECK_OK);
 
-    ExpressionClassifier pattern_classifier;
-    Expression* pattern = ParsePrimaryExpression(&pattern_classifier, CHECK_OK);
-    ValidateBindingPattern(&pattern_classifier, CHECK_OK);
-
-    const AstRawString* name = ast_value_factory()->dot_catch_string();
-    bool is_simple = pattern->IsVariableProxy();
-    if (is_simple) {
-      auto proxy = pattern->AsVariableProxy();
-      scope_->RemoveUnresolved(proxy);
-      name = proxy->raw_name();
-    }
+    Expect(Token::RPAREN, CHECK_OK);
 
     catch_variable = catch_scope->DeclareLocal(name, VAR, kCreatedInitialized,
                                                Variable::NORMAL);
-
-    Expect(Token::RPAREN, CHECK_OK);
-
-    {
     BlockState block_state(&scope_, catch_scope);
-
-      // TODO(adamk): Make a version of ParseScopedBlock that takes a scope and
-      // a block.
-      catch_block =
-          factory()->NewBlock(nullptr, 16, false, RelocInfo::kNoPosition);
-      Scope* block_scope = NewScope(scope_, BLOCK_SCOPE);
-
-      block_scope->set_start_position(scanner()->location().beg_pos);
-      {
-        BlockState block_state(&scope_, block_scope);
-        Target target(&this->target_stack_, catch_block);
-
-        if (!is_simple) {
-          DeclarationDescriptor descriptor;
-          descriptor.declaration_kind = DeclarationDescriptor::NORMAL;
-          descriptor.parser = this;
-          descriptor.declaration_scope = scope_;
-          descriptor.scope = scope_;
-          descriptor.hoist_scope = nullptr;
-          descriptor.mode = LET;
-          descriptor.is_const = false;
-          descriptor.needs_init = true;
-          descriptor.declaration_pos = pattern->position();
-          descriptor.init_op = Token::INIT_LET;
-
-          DeclarationParsingResult::Declaration decl(
-              pattern, pattern->position(),
-              factory()->NewVariableProxy(catch_variable));
-
-          PatternRewriter::DeclareAndInitializeVariables(
-              catch_block, &descriptor, &decl, nullptr, CHECK_OK);
-        }
-
-        Expect(Token::LBRACE, CHECK_OK);
-        while (peek() != Token::RBRACE) {
-          Statement* stat = ParseStatementListItem(CHECK_OK);
-          if (stat && !stat->IsEmpty()) {
-            catch_block->statements()->Add(stat, zone());
-          }
-        }
-        Consume(Token::RBRACE);
-      }
-      block_scope->set_end_position(scanner()->location().end_pos);
-      block_scope = block_scope->FinalizeBlockScope();
-      catch_block->set_scope(block_scope);
-    }
+    catch_block = ParseBlock(NULL, CHECK_OK);
 
     catch_scope->set_end_position(scanner()->location().end_pos);
     tok = peek();
@@ -4422,8 +4364,7 @@ FunctionLiteral* Parser::ParseFunctionLiteral(
     if (is_sloppy(language_mode) && allow_harmony_sloppy_function()) {
       InsertSloppyBlockFunctionVarBindings(scope, CHECK_OK);
     }
-    if (is_strict(language_mode) || allow_harmony_sloppy() ||
-        allow_harmony_destructuring()) {
+    if (is_strict(language_mode) || allow_harmony_sloppy()) {
       CheckConflictingVarDeclarations(scope, CHECK_OK);
     }
   }

src/preparser.cc

@@ -1029,12 +1029,9 @@ PreParser::Statement PreParser::ParseTryStatement(bool* ok) {
   if (tok == Token::CATCH) {
     Consume(Token::CATCH);
     Expect(Token::LPAREN, CHECK_OK);
-    ExpressionClassifier pattern_classifier;
-    ParsePrimaryExpression(&pattern_classifier, CHECK_OK);
-    ValidateBindingPattern(&pattern_classifier, CHECK_OK);
+    ParseIdentifier(kDontAllowRestrictedIdentifiers, CHECK_OK);
     Expect(Token::RPAREN, CHECK_OK);
     {
-      // TODO(adamk): Make this CATCH_SCOPE
       Scope* with_scope = NewScope(scope_, WITH_SCOPE);
       BlockState block_state(&scope_, with_scope);
       ParseBlock(CHECK_OK);

test/cctest/test-parsing.cc

@@ -6514,7 +6514,6 @@ TEST(DestructuringPositiveTests) {
                                    {"function f(argument1, ", ") {}"},
                                    {"var f = (", ") => {};"},
                                    {"var f = (argument1,", ") => {};"},
-                                   {"try {} catch(", ") {}"},
                                    {NULL, NULL}};
 
   // clang-format off
@@ -6576,7 +6575,6 @@ TEST(DestructuringNegativeTests) {
                                      {"var f = (", ") => {};"},
                                      {"var f = ", " => {};"},
                                      {"var f = (argument1,", ") => {};"},
-                                     {"try {} catch(", ") {}"},
                                      {NULL, NULL}};
 
     // clang-format off

test/message/try-catch-lexical-conflict.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.
-//
-// Flags: --harmony-destructuring
-
-"use strict";
-try {
-} catch ({x}) {
-  let x;
-}

test/message/try-catch-lexical-conflict.out

-*%(basename)s:10: SyntaxError: Identifier 'x' has already been declared
-  let x;
-       ^
-SyntaxError: Identifier 'x' has already been declared

test/message/try-catch-variable-conflict.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.
-//
-// Flags: --harmony-destructuring
-
-try {
-} catch ({x}) {
-  var x;
-}

test/message/try-catch-variable-conflict.out

-*%(basename)s:9: SyntaxError: Identifier 'x' has already been declared
-  var x;
-       ^
-SyntaxError: Identifier 'x' has already been declared

test/mjsunit/harmony/destructuring.js

@@ -1107,30 +1107,3 @@
 (function TestDestructuringArrayWithoutInitializer() {
   assertThrows('var [foo]', TypeError);
 })();
-
-
-(function TestCatch() {
-  "use strict";
-
-  // For testing proper scoping.
-  var foo = "hello", bar = "world", baz = 42;
-
-  try {
-    throw {foo: 1, bar: 2};
-  } catch ({foo, bar, baz = 3}) {
-    assertEquals(1, foo);
-    assertEquals(2, bar);
-    assertEquals(3, baz);
-  }
-
-  try {
-    throw [1, 2, 3];
-  } catch ([foo, ...bar]) {
-    assertEquals(1, foo);
-    assertEquals([2, 3], bar);
-  }
-
-  assertEquals("hello", foo);
-  assertEquals("world", bar);
-  assertEquals(42, baz);
-})();