anchor.diff:  
   import '../fasta_codes.dart' show templateUnspecified;
   
  -import '../problems.dart' show unhandled, unimplemented;
  +import '../problems.dart' show internalProblem, unhandled, unimplemented;
   
   import '../kernel/kernel_builder.dart'
       show
  
positive.code:       } else {
          unhandled("${node.runtimeType}", "finalizeExports", -1, fileUri);
        }
        var library = loader.read(libraryUri, -1);
        Builder builder;
        if (isSetter) {
          builder = library.exportScope.setters[name];
  
negative.code:         builder = library.exportScope.local[name];
          exportScopeBuilder.addMember(name, builder);
        }
        if (builder == null) {
          internalProblem(
              templateUnspecified.withArguments(
                  "Exported element '$name' not found in '$libraryUri'."),
              -1,
              fileUri);
        }
        assert(node == builder.target);
      }
    }
  