Get rid of old code for union/intersection in HType.

sdk/lib/_internal/compiler/implementation/universe/universe.dart

 // Copyright (c) 2012, 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 universe;
 
 import '../closure.dart';
 import '../elements/elements.dart';
 import '../dart2jslib.dart';
 import '../dart_types.dart';
@@ skipping 441 matching lines @@
   final TypeMask mask;
 
   TypedSelector(this.mask, Selector selector)
       : asUntyped = selector.asUntyped,
         super(selector.kind,
               selector.name,
               selector.library,
               selector.argumentCount,
               selector.namedArguments) {
     // Invariant: Typed selector can not be based on a malformed type.
-    assert(!identical(mask.base.kind, TypeKind.MALFORMED_TYPE));
+    assert(mask.isEmpty || !identical(mask.base.kind, TypeKind.MALFORMED_TYPE));
     assert(asUntyped.mask == null);
   }
 
   TypedSelector.exact(DartType base, Selector selector)
       : this(new TypeMask.exact(base), selector);
 
   TypedSelector.subclass(DartType base, Selector selector)
       : this(new TypeMask.subclass(base), selector);
 
   TypedSelector.subtype(DartType base, Selector selector)
@@ skipping 24 matching lines @@
     // A closure can be called through any typed selector:
     // class A {
     //   get foo => () => 42;
     //   bar() => foo(); // The call to 'foo' is a typed selector.
     // }
     ClassElement other = element.getEnclosingClass();
     if (identical(other.superclass, compiler.closureClass)) {
       return appliesUntyped(element, compiler);
     }
 
+    if (mask.isEmpty) {
+      if (!mask.isNullable) return false;
+      return hasElementIn(compiler.backend.jsNullClass, element)
+          && appliesUntyped(element, compiler);
+    }
+
     // TODO(kasperl): Can't we just avoid creating typed selectors
     // based of function types?
     Element self = mask.base.element;
     if (self.isTypedef()) {
       // A typedef is a function type that doesn't have any
       // user-defined members.
       return false;
     }
 
     if (mask.isNullable && compiler.backend.isNullImplementation(other)) {
@@ skipping 19 matching lines @@
       ClassElement cls = self;
       if (cls.isSubclassOf(other)) {
         // Resolve an invocation of [element.name] on [self]. If it
         // is found, this selector is a candidate.
         return hasElementIn(cls, element) && appliesUntyped(element, compiler);
       }
     }
     return false;
   }
 }