[runtime] Throw exception for derived constructors in correct context.

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 2707 matching lines @@
                       MessageTemplate::kStrongConstructorReturnValue);
       *ok = false;
       return NULL;
     }
 
     int pos = peek_position();
     return_value = ParseExpression(true, CHECK_OK);
 
     if (IsSubclassConstructor(function_state_->kind())) {
       // For subclass constructors we need to return this in case of undefined
-      // and throw an exception in case of a non object.
+      // return a Smi (transformed into an exception in the ConstructStub)
+      // for a non object.
       //
       //   return expr;
       //
       // Is rewritten as:
       //
       //   return (temp = expr) === undefined ? this :
-      //       %_IsJSReceiver(temp) ? temp : throw new TypeError(...);
+      //       %_IsJSReceiver(temp) ? temp : 1;
+
+      // temp = expr
       Variable* temp = scope_->NewTemporary(
           ast_value_factory()->empty_string());
       Assignment* assign = factory()->NewAssignment(
           Token::ASSIGN, factory()->NewVariableProxy(temp), return_value, pos);
 
-      Expression* throw_expression =
-          NewThrowTypeError(MessageTemplate::kDerivedConstructorReturn,
-                            ast_value_factory()->empty_string(), pos);
-
       // %_IsJSReceiver(temp)
       ZoneList<Expression*>* is_spec_object_args =
           new (zone()) ZoneList<Expression*>(1, zone());
       is_spec_object_args->Add(factory()->NewVariableProxy(temp), zone());
       Expression* is_spec_object_call = factory()->NewCallRuntime(
           Runtime::kInlineIsJSReceiver, is_spec_object_args, pos);
 
       // %_IsJSReceiver(temp) ? temp : throw_expression
       Expression* is_object_conditional = factory()->NewConditional(
           is_spec_object_call, factory()->NewVariableProxy(temp),
-          throw_expression, pos);
+          factory()->NewSmiLiteral(1, pos), pos);
 
       // temp === undefined
       Expression* is_undefined = factory()->NewCompareOperation(
           Token::EQ_STRICT, assign,
           factory()->NewUndefinedLiteral(RelocInfo::kNoPosition), pos);
 
       // is_undefined ? this : is_object_conditional
       return_value = factory()->NewConditional(
           is_undefined, ThisExpression(scope_, factory(), pos),
           is_object_conditional, pos);
@@ skipping 2932 matching lines @@
     auto class_literal = value->AsClassLiteral();
     if (class_literal->raw_name() == nullptr) {
       class_literal->set_raw_name(name);
     }
   }
 }
 
 
 }  // namespace internal
 }  // namespace v8