Fix completion value of empty catch block in the presence of destructuring.

src/parsing/parser.cc

 // Copyright 2012 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.
 
 #include "src/parsing/parser.h"
 
 #include "src/api.h"
 #include "src/ast/ast.h"
 #include "src/ast/ast-expression-rewriter.h"
 #include "src/ast/ast-expression-visitor.h"
@@ skipping 3083 matching lines @@
           descriptor.scope = scope_;
           descriptor.hoist_scope = nullptr;
           descriptor.mode = LET;
           descriptor.declaration_pos = pattern->position();
           descriptor.initialization_pos = pattern->position();
 
           DeclarationParsingResult::Declaration decl(
               pattern, pattern->position(),
               factory()->NewVariableProxy(catch_variable));
 
+          Block* init_block =
+              factory()->NewBlock(nullptr, 8, true, RelocInfo::kNoPosition);
           PatternRewriter::DeclareAndInitializeVariables(
-              catch_block, &descriptor, &decl, nullptr, CHECK_OK);
+              init_block, &descriptor, &decl, nullptr, CHECK_OK);
+          catch_block->statements()->Add(init_block, zone());
         }
 
         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);
@@ skipping 3777 matching lines @@
   Expression* do_each =
       factory->NewDoExpression(new_assign_each, var_each, nopos);
   loop->set_assign_each(do_each);
 
   return final_loop;
 }
 
 
 }  // namespace internal
 }  // namespace v8