More precise result types for contructor calls

src/typing.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 544 matching lines @@
   // Collect type feedback.
   expr->RecordTypeFeedback(oracle());
 
   RECURSE(Visit(expr->expression()));
   ZoneList<Expression*>* args = expr->arguments();
   for (int i = 0; i < args->length(); ++i) {
     Expression* arg = args->at(i);
     RECURSE(Visit(arg));
   }
 
-  // We don't know anything about the result type.
+  NarrowType(expr, Bounds(Type::None(zone()), Type::Receiver(zone())));
 }
 
 
 void AstTyper::VisitCallRuntime(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   for (int i = 0; i < args->length(); ++i) {
     Expression* arg = args->at(i);
     RECURSE(Visit(arg));
   }
 
@@ skipping 216 matching lines @@
 void AstTyper::VisitModuleUrl(ModuleUrl* module) {
 }
 
 
 void AstTyper::VisitModuleStatement(ModuleStatement* stmt) {
   RECURSE(Visit(stmt->body()));
 }
 
 
 } }  // namespace v8::internal