Fix type inference of getters that "override" setters and vice versa.

pkg/kernel/test/class_hierarchy_test.dart

 // Copyright (c) 2017, 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:kernel/ast.dart';
 import 'package:kernel/class_hierarchy.dart';
 import 'package:kernel/core_types.dart';
 import 'package:kernel/src/incremental_class_hierarchy.dart';
 import 'package:kernel/testing/mock_sdk_program.dart';
 import 'package:kernel/text/ast_to_text.dart';
@@ skipping 977 matching lines @@
     var b_int = new InterfaceType(b, [int]);
     expect(hierarchy.getTypeAsInstanceOf(b_int, a),
         new InterfaceType(a, [int, bool]));
     expect(hierarchy.getTypeAsInstanceOf(b_int, objectClass),
         new InterfaceType(objectClass));
   }
 
   void _assertOverridePairs(Class class_, List<String> expected,
       {bool crossGettersSetters: false}) {
     List<String> overrideDescriptions = [];
-    hierarchy.forEachOverridePair(class_,
-        (Member declaredMember, Member interfaceMember, bool isSetter) {
+    void callback(
+        Member declaredMember, Member interfaceMember, bool isSetter) {
       String declaredSuffix;
       String interfaceSuffix;
+      declaredSuffix = isSetter ? '=' : '';
       if (crossGettersSetters) {
-        declaredSuffix = _isSetter(declaredMember) ? '=' : '';
-        interfaceSuffix = _isSetter(interfaceMember) ? '=' : '';
+        interfaceSuffix = isSetter ? '' : '=';
       } else {
-        declaredSuffix = isSetter ? '=' : '';
         interfaceSuffix = isSetter ? '=' : '';
       }
       String declaredName = '$declaredMember$declaredSuffix';
       String interfaceName = '$interfaceMember$interfaceSuffix';
       var desc = '$declaredName overrides $interfaceName';
       overrideDescriptions.add(desc);
-    }, crossGettersSetters: crossGettersSetters);
+    }
+
+    if (crossGettersSetters) {
+      hierarchy.forEachCrossOverridePair(class_, callback);
+    } else {
+      hierarchy.forEachOverridePair(class_, callback);
+    }
     expect(overrideDescriptions, unorderedEquals(expected));
   }
 
   /// Assert that the test [library] has the [expectedText] presentation.
   /// The presentation is close, but not identical to the normal Kernel one.
   void _assertTestLibraryText(String expectedText) {
     StringBuffer sb = new StringBuffer();
     Printer printer = new Printer(sb);
     printer.writeLibraryFile(library);
 
@@ skipping 12 matching lines @@
     actualText = actualText.replaceAll('{\n}', '{}');
     actualText = actualText.replaceAll(' extends core::Object', '');
 
     if (actualText != expectedText) {
       print('-------- Actual --------');
       print(actualText + '------------------------');
     }
 
     expect(actualText, expectedText);
   }
-
-  static bool _isSetter(Member member) {
-    return member is Procedure && member.kind == ProcedureKind.Setter;
-  }
 }