Fixes assert assignable check for DBC

runtime/vm/simulator_dbc.cc

 // Copyright (c) 2016, 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 <setjmp.h>  // NOLINT
 #include <stdlib.h>
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_DBC)
 
@@ skipping 1616 matching lines @@
     NativeArguments args(thread, 2, SP + 1, SP - 1);
     INVOKE_RUNTIME(DRT_AllocateArray, args);
     SP -= 1;
     DISPATCH();
   }
 
   {
     BYTECODE(AssertAssignable, A_D);  // Stack: instance, type args, type, name
     RawObject** args = SP - 3;
     if (args[0] != null_value) {
+      const AbstractType& dst_type =
+          AbstractType::Handle(static_cast<RawAbstractType*>(args[2]));
+      if (dst_type.IsMalformedOrMalbounded()) {
+        SP[1] = args[0];  // instance.
+        SP[2] = args[3];  // name.
+        SP[3] = args[2];  // type.
+        Exit(thread, FP, SP + 4, pc);
+        NativeArguments args(thread, 3, SP + 1, SP - 3);
+        INVOKE_RUNTIME(DRT_BadTypeError, args);
+        UNREACHABLE();
+      }
+
       RawSubtypeTestCache* cache =
           static_cast<RawSubtypeTestCache*>(LOAD_CONSTANT(rD));
       if (cache != null_value) {
         RawInstance* instance = static_cast<RawInstance*>(args[0]);
         RawTypeArguments* instantiator_type_arguments =
             static_cast<RawTypeArguments*>(args[1]);
 
         const intptr_t cid = SimulatorHelpers::GetClassId(instance);
 
         RawTypeArguments* instance_type_arguments =
@@ skipping 246 matching lines @@
   special_[kExceptionSpecialIndex] = raw_exception;
   special_[kStacktraceSpecialIndex] = raw_stacktrace;
   buf->Longjmp();
   UNREACHABLE();
 }
 
 }  // namespace dart
 
 
 #endif  // defined TARGET_ARCH_DBC