fix #30030, fix #27327 - fix tearoffs and various Object member bugs

pkg/dev_compiler/lib/src/compiler/js_typeref_codegen.dart

 // Copyright (c) 2015, 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.
 
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/generated/resolver.dart' show TypeProvider;
 import 'package:analyzer/src/generated/utilities_dart.dart';
 
 import '../js_ast/js_ast.dart' as JS;
 import 'compiler.dart' show CompilerOptions;
 import 'js_interop.dart';
 
 /// Mixin with logic to generate [TypeRef]s out of [DartType]s.
 abstract class JsTypeRefCodegen {
   final _resolved = <DartType, JS.TypeRef>{};
 
   // Mixin dependencies:
   CompilerOptions get options;
   TypeProvider get types;
   LibraryElement get dartJSLibrary;
   JS.Identifier get namedArgumentTemp;
   JS.Identifier emitLibraryName(LibraryElement e);
 
   /// Finds the qualified path to the type.
   JS.TypeRef _emitTopLevelTypeRef(DartType type) {
     var e = type.element;
-    return new JS.TypeRef.qualified(
-        [emitLibraryName(e.library), new JS.Identifier(getJSExportName(e))]);
+    return new JS.TypeRef.qualified([
+      emitLibraryName(e.library),
+      new JS.Identifier(getJSExportName(e) ?? e.name)
+    ]);
   }
 
   JS.TypeRef emitTypeRef(DartType type) {
     if (!options.closure) return null;
 
     return _resolved.putIfAbsent(type, () {
       if (type == null) new JS.TypeRef.unknown();
       // TODO(ochafik): Consider calling _loader.declareBeforeUse(type.element).
       if (type.isBottom || type.isDynamic) new JS.TypeRef.any();
       if (type.isVoid) return new JS.TypeRef.void_();
@@ skipping 79 matching lines @@
                   : null);
         case 'JsObject':
           return new JS.TypeRef.object();
         case 'JsFunction':
           return new JS.TypeRef.function();
       }
     }
     return null;
   }
 }