Allow 'void' as a type argument (fixes #28945).

runtime/vm/object.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/become.h"
@@ skipping 15860 matching lines @@
           bound_error, NULL, NULL, Heap::kOld);
       if ((bound_error != NULL) && !bound_error->IsNull()) {
         ASSERT(Isolate::Current()->type_checks());
         return false;
       }
       if (instantiated_other.IsTypeRef()) {
         instantiated_other = TypeRef::Cast(instantiated_other).type();
       }
       if (instantiated_other.IsDynamicType() ||
           instantiated_other.IsObjectType() ||
+          instantiated_other.IsVoidType() ||
           instantiated_other.IsDartFunctionType()) {
         return true;
       }
     }
     if (!instantiated_other.IsFunctionType()) {
       return false;
     }
     Function& other_signature =
         Function::Handle(zone, Type::Cast(instantiated_other).signature());
     Function& sig_fun = Function::Handle(zone, Closure::Cast(*this).function());
@@ skipping 30 matching lines @@
     instantiated_other = other.InstantiateFrom(
         other_instantiator_type_arguments, other_function_type_arguments,
         bound_error, NULL, NULL, Heap::kOld);
     if ((bound_error != NULL) && !bound_error->IsNull()) {
       ASSERT(Isolate::Current()->type_checks());
       return false;
     }
     if (instantiated_other.IsTypeRef()) {
       instantiated_other = TypeRef::Cast(instantiated_other).type();
     }
-    if (instantiated_other.IsDynamicType()) {
+    if (instantiated_other.IsDynamicType() ||
+        instantiated_other.IsObjectType() || instantiated_other.IsVoidType()) {
       return true;
     }
   }
   other_type_arguments = instantiated_other.arguments();
   const bool other_is_dart_function = instantiated_other.IsDartFunctionType();
   if (other_is_dart_function || instantiated_other.IsFunctionType()) {
     // Check if this instance understands a call() method of a compatible type.
     Function& sig_fun =
         Function::Handle(zone, cls.LookupCallFunctionForTypeTest());
     if (!sig_fun.IsNull()) {
@@ skipping 14 matching lines @@
       }
     }
   }
   if (!instantiated_other.IsType()) {
     return false;
   }
   other_class = instantiated_other.type_class();
   if (IsNull()) {
     ASSERT(cls.IsNullClass());
     // As of Dart 1.5, the null instance and Null type are handled differently.
-    // We already checked for other.IsDynamicType().
+    // We already checked other for dynamic and void.
     return other_class.IsNullClass() || other_class.IsObjectClass();
   }
   return cls.IsSubtypeOf(type_arguments, other_class, other_type_arguments,
                          bound_error, NULL, Heap::kOld);
 }
 
 
 bool Instance::OperatorEquals(const Instance& other) const {
   // TODO(koda): Optimize for all builtin classes and all classes
   // that do not override operator==.
@@ skipping 7377 matching lines @@
   return UserTag::null();
 }
 
 
 const char* UserTag::ToCString() const {
   const String& tag_label = String::Handle(label());
   return tag_label.ToCString();
 }
 
 }  // namespace dart