Issue 28027. Move Null to the bottom in the Analyzer.

pkg/analyzer/lib/src/generated/element_resolver.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 analyzer.src.generated.element_resolver;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/syntactic_entity.dart';
@@ skipping 1298 matching lines @@
             // be the case that static type is some type, in which the static
             // type should be used.
             targetType = _getBestType(target);
           }
           if (targetType == null) {
             if (target is Identifier &&
                 _resolver.nameScope.shouldIgnoreUndefined(target)) {
               return null;
             }
             return StaticTypeWarningCode.UNDEFINED_FUNCTION;
-          } else if (!targetType.isDynamic && !targetType.isBottom) {
+          } else if (!targetType.isDynamic && target is! NullLiteral) {
             // Proxy-conditional warning, based on state of
             // targetType.getElement()
             return StaticTypeWarningCode.UNDEFINED_METHOD;
           }
         }
       }
     }
     return null;
   }
 
@@ skipping 224 matching lines @@
       // All function types are subtypes of 'Function', which is itself a
       // subclass of 'Object'.
       //
       staticType = _resolver.typeProvider.functionType;
     }
     return staticType;
   }
 
   DartType _getStaticTypeOrFunctionType(Expression expression) {
     if (expression is NullLiteral) {
-      return _resolver.typeProvider.bottomType;
+      return _resolver.typeProvider.nullType;
     }
     return _resolveTypeParameter(expression.staticType);
   }
 
   /**
    * Check for a generic method & apply type arguments if any were passed.
    */
   DartType _instantiateGenericMethod(
       DartType invokeType, TypeArgumentList typeArguments, AstNode node) {
     // TODO(jmesserly): support generic "call" methods on InterfaceType.
@@ skipping 916 matching lines @@
    * be used when looking up members. Otherwise, return the original type.
    */
   DartType _resolveTypeParameter(DartType type) =>
       type?.resolveToBound(_resolver.typeProvider.objectType);
 
   /**
    * Return `true` if we should report an error as a result of looking up a
    * [member] in the given [type] and not finding any member.
    */
   bool _shouldReportMissingMember(DartType type, Element member) {
-    return member == null && type != null && !type.isDynamic && !type.isBottom;
+    return member == null && type != null && !type.isDynamic && !type.isDartCoreNull;
   }
 
   /**
    * Checks whether the given [expression] is a reference to a class. If it is
    * then the element representing the class is returned, otherwise `null` is
    * returned.
    */
   static ClassElement getTypeReference(Expression expression) {
     if (expression is Identifier) {
       Element staticElement = expression.staticElement;
@@ skipping 133 matching lines @@
 
   @override
   Element get staticElement => null;
 
   @override
   dynamic/*=E*/ accept/*<E>*/(AstVisitor/*<E>*/ visitor) => null;
 
   @override
   void visitChildren(AstVisitor visitor) {}
 }