Skip abstract methods in member lookup for inference.

Change-Id: Ic07e1f6f038ebf6a9767c65777c0d6898131b632
Reviewed-on: https://dart-review.googlesource.com/19000
Reviewed-by: Sigmund Cherem <sigmund@google.com>

pkg/compiler/lib/src/kernel/element_map_impl.dart

@@ -1747,6 +1747,7 @@ abstract class KernelClosedWorldMixin implements ClosedWorldBase {
           cls, selector.name,
           setter: selector.isSetter);
       if (member != null &&
+          !member.isAbstract &&
           (!selector.memberName.isPrivate ||
               member.library == selector.library)) {
         return member == element;

tests/compiler/dart2js/equivalence/id_equivalence_helper.dart

@@ -98,6 +98,9 @@ Future<CompiledData> computeData(
   }
 
   void processMember(MemberEntity member) {
+    if (member.isAbstract) {
+      return;
+    }
     if (skipUnprocessedMembers &&
         !closedWorld.processedMembers.contains(member)) {
       return;
@@ -455,6 +458,7 @@ Future<bool> compareData(
     bool skipUnprocessedMembers: false,
     bool skipFailedCompilations: false,
     bool verbose: false}) async {
+  print('--from ast----------------------------------------------------------');
   CompiledData data1 = await computeData(
       entryPoint, memorySourceFiles, computeAstData,
       options: options,
@@ -462,6 +466,7 @@ Future<bool> compareData(
       skipUnprocessedMembers: skipUnprocessedMembers,
       skipFailedCompilations: skipFailedCompilations);
   if (data1 == null) return false;
+  print('--from kernel-------------------------------------------------------');
   CompiledData data2 = await computeData(
       entryPoint, memorySourceFiles, computeIrData,
       options: [Flags.useKernel]..addAll(options),

tests/compiler/dart2js/inference/data/abstract_method.dart

@@ -0,0 +1,20 @@
+// 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.
+
+/*element: main:[null]*/
+main() {
+  abstractEquals();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Call abstract method implemented by superclass.
+////////////////////////////////////////////////////////////////////////////////
+
+/*element: Class1.:[exact=Class1]*/
+class Class1 {
+  operator ==(_);
+}
+
+/*element: abstractEquals:[exact=JSBool]*/
+abstractEquals() => new Class1() /*invoke: [exact=Class1]*/ == new Class1();

tests/compiler/dart2js/inference/data/expose_this_mask.dart

@@ -280,7 +280,6 @@ abstract class Class8 {
     /*invoke: [subclass=Class8]*/ method8();
   }
 
-  /*element: Class8.method8:[empty]*/
   method8();
 }