Remove unused is_class_scope bit from Scope and ScopeInfo

This was added in https://chromium.googlesource.com/v8/v8/+/4a709dd65,
but the only check for it that remained in the final patch is inside
a DCHECK. It appears that the approach for checking use of class names
in methods evolved quite a bit over the review of the original patch.

Review URL: https://codereview.chromium.org/1219993002

Cr-Commit-Position: refs/heads/master@{#29428}

src/objects.h

@@ -4029,7 +4029,6 @@ class ScopeInfo : public FixedArray {
   // context-allocated.  Otherwise returns a value < 0.
   int ReceiverContextSlotIndex();
 
-  bool block_scope_is_class_scope();
   FunctionKind function_kind();
 
   // Copies all the context locals into an object used to materialize a scope.
@@ -4157,10 +4156,8 @@ class ScopeInfo : public FixedArray {
   class AsmFunctionField : public BitField<bool, AsmModuleField::kNext, 1> {};
   class IsSimpleParameterListField
       : public BitField<bool, AsmFunctionField::kNext, 1> {};
-  class BlockScopeIsClassScopeField
-      : public BitField<bool, IsSimpleParameterListField::kNext, 1> {};
   class FunctionKindField
-      : public BitField<FunctionKind, BlockScopeIsClassScopeField::kNext, 8> {};
+      : public BitField<FunctionKind, IsSimpleParameterListField::kNext, 8> {};
 
   // BitFields representing the encoded information for context locals in the
   // ContextLocalInfoEntries part.

src/parser.cc

@@ -4455,11 +4455,7 @@ ClassLiteral* Parser::ParseClassLiteral(const AstRawString* name,
     return NULL;
   }
 
-  // Create a block scope which is additionally tagged as class scope; this is
-  // important for resolving variable references to the class name in the strong
-  // mode.
   Scope* block_scope = NewScope(scope_, BLOCK_SCOPE);
-  block_scope->tag_as_class_scope();
   BlockState block_state(&scope_, block_scope);
   scope_->SetLanguageMode(
       static_cast<LanguageMode>(scope_->language_mode() | STRICT_BIT));

src/scopeinfo.cc

@@ -89,7 +89,6 @@ Handle<ScopeInfo> ScopeInfo::Create(Isolate* isolate, Zone* zone,
               AsmModuleField::encode(scope->asm_module()) |
               AsmFunctionField::encode(scope->asm_function()) |
               IsSimpleParameterListField::encode(simple_parameter_list) |
-              BlockScopeIsClassScopeField::encode(scope->is_class_scope()) |
               FunctionKindField::encode(scope->function_kind());
   scope_info->SetFlags(flags);
   scope_info->SetParameterCount(parameter_count);
@@ -223,7 +222,6 @@ Handle<ScopeInfo> ScopeInfo::CreateGlobalThisBinding(Isolate* isolate) {
               FunctionVariableMode::encode(function_variable_mode) |
               AsmModuleField::encode(false) | AsmFunctionField::encode(false) |
               IsSimpleParameterListField::encode(simple_parameter_list) |
-              BlockScopeIsClassScopeField::encode(false) |
               FunctionKindField::encode(FunctionKind::kNormalFunction);
   scope_info->SetFlags(flags);
   scope_info->SetParameterCount(parameter_count);
@@ -567,11 +565,6 @@ int ScopeInfo::FunctionContextSlotIndex(String* name, VariableMode* mode) {
 }
 
 
-bool ScopeInfo::block_scope_is_class_scope() {
-  return BlockScopeIsClassScopeField::decode(Flags());
-}
-
-
 FunctionKind ScopeInfo::function_kind() {
   return FunctionKindField::decode(Flags());
 }

src/scopes.cc

@@ -152,7 +152,6 @@ void Scope::SetDefaults(ScopeType scope_type, Scope* outer_scope,
   outer_scope_ = outer_scope;
   scope_type_ = scope_type;
   function_kind_ = function_kind;
-  block_scope_is_class_scope_ = false;
   scope_name_ = ast_value_factory_->empty_string();
   dynamics_ = nullptr;
   receiver_ = nullptr;
@@ -189,7 +188,6 @@ void Scope::SetDefaults(ScopeType scope_type, Scope* outer_scope,
   if (!scope_info.is_null()) {
     scope_calls_eval_ = scope_info->CallsEval();
     language_mode_ = scope_info->language_mode();
-    block_scope_is_class_scope_ = scope_info->block_scope_is_class_scope();
     function_kind_ = scope_info->function_kind();
   }
 }
@@ -1232,7 +1230,6 @@ ClassVariable* Scope::ClassVariableForMethod() const {
     return nullptr;
   }
   DCHECK_NOT_NULL(outer_scope_);
-  DCHECK(outer_scope_->is_class_scope());
   // The class scope contains at most one variable, the class name.
   DCHECK(outer_scope_->variables_.occupancy() <= 1);
   if (outer_scope_->variables_.occupancy() == 0) return nullptr;

src/scopes.h

@@ -280,13 +280,6 @@ class Scope: public ZoneObject {
   bool is_block_scope() const { return scope_type_ == BLOCK_SCOPE; }
   bool is_with_scope() const { return scope_type_ == WITH_SCOPE; }
   bool is_arrow_scope() const { return scope_type_ == ARROW_SCOPE; }
-  void tag_as_class_scope() {
-    DCHECK(is_block_scope());
-    block_scope_is_class_scope_ = true;
-  }
-  bool is_class_scope() const {
-    return is_block_scope() && block_scope_is_class_scope_;
-  }
   bool is_declaration_scope() const {
     return is_eval_scope() || is_function_scope() ||
         is_module_scope() || is_script_scope();
@@ -544,8 +537,6 @@ class Scope: public ZoneObject {
 
   // The scope type.
   ScopeType scope_type_;
-  // Some block scopes are tagged as class scopes.
-  bool block_scope_is_class_scope_;
   // If the scope is a function scope, this is the function kind.
   FunctionKind function_kind_;