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

pkg/kernel/lib/src/incremental_class_hierarchy.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.
 library kernel.incremental_class_hierarchy;
 
 import 'dart:collection';
 import 'dart:math';
 
 import 'package:kernel/ast.dart';
 import 'package:kernel/class_hierarchy.dart';
@@ skipping 68 matching lines @@
   final Map<Class, _ClassInfo> _info = new LinkedHashMap<Class, _ClassInfo>();
 
   @override
   ClassHierarchy applyChanges(Iterable<Class> classes) {
     if (classes.isEmpty) return this;
     return new IncrementalClassHierarchy();
   }
 
   @override
   void forEachOverridePair(Class node,
-      callback(Member declaredMember, Member interfaceMember, bool isSetter),
-      {bool crossGettersSetters: false}) {
+      callback(Member declaredMember, Member interfaceMember, bool isSetter)) {
     _ClassInfo info = _getInfo(node);
     for (var supertype in node.supers) {
       var superNode = supertype.classNode;
       var superInfo = _getInfo(superNode);
 
       var superGetters = superInfo.interfaceGettersAndCalls;
       var superSetters = superInfo.interfaceSetters;
 
       _reportOverrides(info.implementedGettersAndCalls, superGetters, callback);
       _reportOverrides(info.declaredGettersAndCalls, superGetters, callback,
           onlyAbstract: true);
 
       _reportOverrides(info.implementedSetters, superSetters, callback,
           isSetter: true);
       _reportOverrides(info.declaredSetters, superSetters, callback,
           isSetter: true, onlyAbstract: true);
-
-      if (crossGettersSetters) {
-        _reportOverrides(info.declaredGettersAndCalls, superSetters, callback);
-        _reportOverrides(info.declaredSetters, superGetters, callback);
-      }
     }
     if (!node.isAbstract) {
       // If a non-abstract class declares an abstract method M whose
       // implementation M' is inherited from the superclass, then the inherited
       // method M' overrides the declared method M.
       // This flies in the face of conventional override logic, but is necessary
       // because an instance of the class will contain the method M' which can
       // be invoked through the interface of M.
       // Note that [_reportOverrides] does not report self-overrides, so in
       // most cases these calls will just scan both lists and report nothing.
       _reportOverrides(info.implementedGettersAndCalls,
           info.declaredGettersAndCalls, callback);
       _reportOverrides(info.implementedSetters, info.declaredSetters, callback,
           isSetter: true);
     }
   }
 
   @override
+  void forEachCrossOverridePair(Class node,
+      callback(Member declaredMember, Member interfaceMember, bool isSetter),
+      {bool crossGettersSetters: false}) {
+    _ClassInfo info = _getInfo(node);
+    for (var supertype in node.supers) {
+      var superNode = supertype.classNode;
+      var superInfo = _getInfo(superNode);
+
+      var superGetters = superInfo.interfaceGettersAndCalls;
+      var superSetters = superInfo.interfaceSetters;
+
+      _reportOverrides(info.declaredGettersAndCalls, superSetters, callback);
+      _reportOverrides(info.declaredSetters, superGetters, callback,
+          isSetter: true);
+    }
+  }
+
+  @override
   Supertype getClassAsInstanceOf(Class node, Class superclass) {
     if (identical(node, superclass)) return node.asThisSupertype;
     _ClassInfo info = _getInfo(node);
     _ClassInfo superInfo = _getInfo(superclass);
     if (!info.isSubtypeOf(superInfo)) return null;
     if (superclass.typeParameters.isEmpty) return superclass.asRawSupertype;
     return info.genericSuperTypes[superclass];
   }
 
   @override
@@ skipping 585 matching lines @@
 class _LubHeap extends Heap<_ClassInfo> {
   @override
   bool sortsBefore(_ClassInfo a, _ClassInfo b) => sortsBeforeStatic(a, b);
 
   static bool sortsBeforeStatic(_ClassInfo a, _ClassInfo b) {
     if (a.depth > b.depth) return true;
     if (a.depth < b.depth) return false;
     return a.id < b.id;
   }
 }