Disallow deferred loading when using isolate reloading.

runtime/vm/object_reload.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 "vm/object.h"
 
 #include "vm/isolate_reload.h"
 #include "vm/log.h"
 #include "vm/resolver.h"
 #include "vm/symbols.h"
@@ skipping 509 matching lines @@
 
   TIR_Print("Class `%s` can be reloaded (%" Pd " and %" Pd ")\n",
             ToCString(),
             id(),
             replacement.id());
   return true;
 }
 
 
 bool Library::CanReload(const Library& replacement) const {
+  // TODO(26878): If the replacement library uses deferred loading,
+  // reject it.  We do not yet support reloading deferred libraries.
+  LibraryPrefix& prefix = LibraryPrefix::Handle();
+  LibraryPrefixIterator it(replacement);
+  while (it.HasNext()) {
+    prefix = it.GetNext();
+    if (prefix.is_deferred_load()) {
+      const String& lib_url = String::Handle(replacement.url());
+      const String& prefix_name = String::Handle(prefix.name());
+      IRC->ReportError(String::Handle(String::NewFormatted(
+          "Reloading support for deferred loading has not yet been implemented:"
+          " library '%s' has deferred import '%s'",
+          lib_url.ToCString(), prefix_name.ToCString())));
+      return false;
+    }
+  }
   return true;
 }
 
 
 static const Function* static_call_target = NULL;
 
 void ICData::Reset() const {
   if (is_static_call()) {
     const Function& old_target = Function::Handle(GetTargetAt(0));
     if (old_target.IsNull()) {
@@ skipping 20 matching lines @@
     }
     ClearAndSetStaticTarget(new_target);
   } else {
     ClearWithSentinel();
   }
 }
 
 #endif  // !PRODUCT
 
 }   // namespace dart.