[es6] Make ParseSuperExpression uses scopes instead

src/preparser.h

 // 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.
 
 #ifndef V8_PREPARSER_H
 #define V8_PREPARSER_H
 
 #include "src/v8.h"
 
 #include "src/bailout-reason.h"
@@ skipping 327 matching lines @@
     }
     ~ParsingModeScope() {
       parser_->mode_ = old_mode_;
     }
 
    private:
     ParserBase* parser_;
     Mode old_mode_;
   };
 
-  Scope* NewScope(Scope* parent, ScopeType scope_type,
-                  FunctionKind kind = kNormalFunction) {
+  Scope* NewScope(Scope* parent, ScopeType scope_type) {
+    // Must always pass the function kind for FUNCTION_SCOPE and ARROW_SCOPE.
+    DCHECK(scope_type != FUNCTION_SCOPE && scope_type != ARROW_SCOPE);
+    return NewScope(parent, scope_type, kNormalFunction);
+  }
+
+  Scope* NewScope(Scope* parent, ScopeType scope_type, FunctionKind kind) {
     DCHECK(ast_value_factory());
     DCHECK(scope_type != MODULE_SCOPE || allow_harmony_modules());
-    DCHECK((scope_type == FUNCTION_SCOPE && IsValidFunctionKind(kind)) ||
-           kind == kNormalFunction);
+    DCHECK(scope_type != ARROW_SCOPE || IsArrowFunction(kind));
     Scope* result = new (zone())
         Scope(zone(), parent, scope_type, ast_value_factory(), kind);
     result->Initialize();
     return result;
   }
 
   Scanner* scanner() const { return scanner_; }
   AstValueFactory* ast_value_factory() const { return ast_value_factory_; }
   int position() { return scanner_->location().beg_pos; }
   int peek_position() { return scanner_->peek_location().beg_pos; }
@@ skipping 1802 matching lines @@
       break;
 
     case Token::LBRACE:
       result = this->ParseObjectLiteral(classifier, CHECK_OK);
       break;
 
     case Token::LPAREN:
       Consume(Token::LPAREN);
       if (allow_harmony_arrow_functions() && Check(Token::RPAREN)) {
         // As a primary expression, the only thing that can follow "()" is "=>".
-        Scope* scope = this->NewScope(scope_, ARROW_SCOPE);
+        Scope* scope =
+            this->NewScope(scope_, ARROW_SCOPE, FunctionKind::kArrowFunction);
         scope->set_start_position(beg_pos);
         FormalParameterErrorLocations error_locs;
         bool has_rest = false;
         result = this->ParseArrowFunctionLiteral(scope, error_locs, has_rest,
                                                  classifier, CHECK_OK);
       } else {
         // Heuristically try to detect immediately called functions before
         // seeing the call parentheses.
         parenthesized_function_ = (peek() == Token::FUNCTION);
         result = this->ParseExpression(true, classifier, CHECK_OK);
@@ skipping 460 matching lines @@
   if (fni_ != NULL) fni_->Enter();
   ParserBase<Traits>::Checkpoint checkpoint(this);
   ExpressionT expression =
       this->ParseConditionalExpression(accept_IN, classifier, CHECK_OK);
 
   if (allow_harmony_arrow_functions() && peek() == Token::ARROW) {
     checkpoint.Restore();
     FormalParameterErrorLocations error_locs;
     Scanner::Location loc(lhs_location.beg_pos, scanner()->location().end_pos);
     bool has_rest = false;
-    Scope* scope = this->NewScope(scope_, ARROW_SCOPE);
+    Scope* scope =
+        this->NewScope(scope_, ARROW_SCOPE, FunctionKind::kArrowFunction);
     scope->set_start_position(lhs_location.beg_pos);
     this->ParseArrowFunctionFormalParameters(scope, expression, loc,
                                              &error_locs, &has_rest, CHECK_OK);
     expression = this->ParseArrowFunctionLiteral(scope, error_locs, has_rest,
                                                  classifier, CHECK_OK);
     return expression;
   }
 
   if (!Token::IsAssignmentOp(peek())) {
     if (fni_ != NULL) fni_->Leave();
@@ skipping 576 matching lines @@
 }
 
 
 template <class Traits>
 typename ParserBase<Traits>::ExpressionT
 ParserBase<Traits>::ParseSuperExpression(bool is_new,
                                          ExpressionClassifier* classifier,
                                          bool* ok) {
   Expect(Token::SUPER, CHECK_OK);
 
-  // TODO(wingo): Does this actually work with lazily compiled arrows?
-  FunctionState* function_state = function_state_;
-  while (IsArrowFunction(function_state->kind())) {
-    function_state = function_state->outer();
+  Scope* scope = scope_->DeclarationScope();
+
+  while (scope->is_eval_scope() || scope->is_arrow_scope()) {
+    scope = scope->outer_scope();
+    DCHECK_NOT_NULL(scope);
+    scope = scope->DeclarationScope();
   }

[wingo, 2015/05/06 14:47:38]

Sounds like we could use a this_declaration_scope() here.

[arv (Not doing code reviews), 2015/05/06 14:57:19]

Yes. That would be perfect for both super and new.target.

-  // TODO(arv): Handle eval scopes similarly.
 
-  FunctionKind kind = function_state->kind();
+  FunctionKind kind = scope->function_kind();
   if (IsConciseMethod(kind) || IsAccessorFunction(kind) ||
       i::IsConstructor(kind)) {
     if (peek() == Token::PERIOD || peek() == Token::LBRACK) {
-      scope_->RecordSuperPropertyUsage();
-      return this->SuperReference(scope_, factory());
+      scope->RecordSuperPropertyUsage();
+      return this->SuperReference(scope, factory());
     }
     // new super() is never allowed.
     // super() is only allowed in derived constructor
     if (!is_new && peek() == Token::LPAREN && IsSubclassConstructor(kind)) {
       if (is_strong(language_mode())) {
         // Super calls in strong mode are parsed separately.
         ReportMessageAt(scanner()->location(), "strong_constructor_super");
         *ok = false;
         return this->EmptyExpression();
       }
-      function_state->set_super_location(scanner()->location());
-      return this->SuperReference(scope_, factory());
+      // TODO(rossberg): This might not be the correct FunctionState for the

[arv (Not doing code reviews), 2015/04/24 15:15:41]

Andreas, I'll remove this todo since you said you think this is correct as is.

One thing I noticed was that commenting out this line does not break any tests.
At this point we do not test `super()` in arrow functions so the problematic
case is never tested.

+      // method here.
+      function_state_->set_super_location(scanner()->location());
+      return this->SuperReference(scope, factory());
     }
   }
 
   ReportMessageAt(scanner()->location(), "unexpected_super");
   *ok = false;
   return this->EmptyExpression();
 }
 
 
 template <class Traits>
@@ skipping 424 matching lines @@
       *ok = false;
       return;
     }
     has_seen_constructor_ = true;
     return;
   }
 }
 } }  // v8::internal
 
 #endif  // V8_PREPARSER_H