Opt-in to generate code for compile-time error. Only supported for SSA.

pkg/compiler/lib/src/deferred_load.dart

 // Copyright (c) 2014, 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.
 
 library deferred_load;
 
 import 'constants/expressions.dart';
 import 'constants/values.dart' show
     ConstantValue,
     ConstructedConstantValue,
@@ skipping 758 matching lines @@
                   : import;
               compiler.reportError(failingImport.prefix,
                   MessageKind.DEFERRED_LIBRARY_DUPLICATE_PREFIX);
             }
             usedPrefixes.add(prefix);
           }
         }
       });
     }
     if (isProgramSplit) {
-      isProgramSplit = compiler.backend.registerDeferredLoading(
+      isProgramSplit = compiler.backend.enableDeferredLoadingIfSupported(
             lastDeferred, compiler.globalDependencies);
     }
   }
 
   /// If [send] is a static send with a deferred element, returns the
   /// [PrefixElement] that the first prefix of the send resolves to.
   /// Otherwise returns null.
   ///
   /// Precondition: send must be static.
   ///
@@ skipping 98 matching lines @@
         _importingLibrary = importingLibrary;
 
   String get importingLibraryName {
     String libraryName = _importingLibrary.getLibraryName();
     return libraryName == ""
       ? "<unnamed>"
       : libraryName;
   }
 
 }