Handle load errors in deferred code

runtime/lib/object.cc

 // Copyright (c) 2011, 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/bootstrap_natives.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/code_patcher.h"
 #include "vm/exceptions.h"
 #include "vm/heap.h"
@@ skipping 272 matching lines @@
 }
 
 
 DEFINE_NATIVE_ENTRY(LibraryPrefix_load, 1) {
   const LibraryPrefix& prefix =
       LibraryPrefix::CheckedHandle(arguments->NativeArgAt(0));
   bool hasCompleted = prefix.LoadLibrary();
   return Bool::Get(hasCompleted).raw();
 }
 
+
+DEFINE_NATIVE_ENTRY(LibraryPrefix_loadError, 1) {
+  const LibraryPrefix& prefix =
+      LibraryPrefix::CheckedHandle(arguments->NativeArgAt(0));
+  // Currently all errors are Dart instances, e.g. I/O errors
+  // created by deferred loading code. LanguageErrors from
+  // failed loading or finalization attempts are propagated and result
+  // in the isolate's death.
+  const Instance& error = Instance::Handle(prefix.LoadError());
+  return error.raw();
+}
+
+
 }  // namespace dart