Revert of Add a separate scope for switch

src/parser.cc

Index: src/parser.cc
diff --git a/src/parser.cc b/src/parser.cc
index 77e17b34e7659d522627749f7e03907a56d3b2c6..a7a31e7173593e67036cf4ffb9de14bb79f2e478 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -2964,72 +2964,31 @@
 }
 
 
-Statement* Parser::ParseSwitchStatement(ZoneList<const AstRawString*>* labels,
-                                        bool* ok) {
+SwitchStatement* Parser::ParseSwitchStatement(
+    ZoneList<const AstRawString*>* labels, bool* ok) {
   // SwitchStatement ::
   //   'switch' '(' Expression ')' '{' CaseClause* '}'
-  // In order to get the CaseClauses to execute in their own lexical scope,
-  // but without requiring downstream code to have special scope handling
-  // code for switch statements, desugar into blocks as follows:
-  // {  // To group the statements--harmless to evaluate Expression in scope
-  //   .tag_variable = Expression;
-  //   {  // To give CaseClauses a scope
-  //     switch (.tag_variable) { CaseClause* }
-  //   }
-  // }
-
-  Block* switch_block =
-      factory()->NewBlock(NULL, 2, true, RelocInfo::kNoPosition);
-  int switch_pos = peek_position();
+
+  SwitchStatement* statement =
+      factory()->NewSwitchStatement(labels, peek_position());
+  Target target(&this->target_stack_, statement);
 
   Expect(Token::SWITCH, CHECK_OK);
   Expect(Token::LPAREN, CHECK_OK);
   Expression* tag = ParseExpression(true, CHECK_OK);
   Expect(Token::RPAREN, CHECK_OK);
 
-  Variable* tag_variable =
-      scope_->NewTemporary(ast_value_factory()->dot_switch_tag_string());
-  Assignment* tag_assign = factory()->NewAssignment(
-      Token::ASSIGN, factory()->NewVariableProxy(tag_variable), tag,
-      tag->position());
-  Statement* tag_statement =
-      factory()->NewExpressionStatement(tag_assign, RelocInfo::kNoPosition);
-  switch_block->AddStatement(tag_statement, zone());
-
-  Block* cases_block =
-      factory()->NewBlock(NULL, 1, true, RelocInfo::kNoPosition);
-  Scope* cases_scope = NewScope(scope_, BLOCK_SCOPE);
-
-  SwitchStatement* switch_statement =
-      factory()->NewSwitchStatement(labels, switch_pos);
-
-  cases_scope->set_start_position(scanner()->location().beg_pos);
-  {
-    BlockState cases_block_state(&scope_, cases_scope);
-    Target target(&this->target_stack_, switch_statement);
-
-    Expression* tag_read = factory()->NewVariableProxy(tag_variable);
-
-    bool default_seen = false;
-    ZoneList<CaseClause*>* cases =
-        new (zone()) ZoneList<CaseClause*>(4, zone());
-    Expect(Token::LBRACE, CHECK_OK);
-    while (peek() != Token::RBRACE) {
-      CaseClause* clause = ParseCaseClause(&default_seen, CHECK_OK);
-      cases->Add(clause, zone());
-    }
-    switch_statement->Initialize(tag_read, cases);
-    cases_block->AddStatement(switch_statement, zone());
+  bool default_seen = false;
+  ZoneList<CaseClause*>* cases = new(zone()) ZoneList<CaseClause*>(4, zone());
+  Expect(Token::LBRACE, CHECK_OK);
+  while (peek() != Token::RBRACE) {
+    CaseClause* clause = ParseCaseClause(&default_seen, CHECK_OK);
+    cases->Add(clause, zone());
   }
   Expect(Token::RBRACE, CHECK_OK);
 
-  cases_scope->set_end_position(scanner()->location().end_pos);
-  cases_scope = cases_scope->FinalizeBlockScope();
-  cases_block->set_scope(cases_scope);
-
-  switch_block->AddStatement(cases_block, zone());
-
-  return switch_block;
+  if (statement) statement->Initialize(tag, cases);
+  return statement;
 }