Set MethodInvocation.interfaceTarget during type inference.

pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.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.
 
 /// This file declares a "shadow hierarchy" of concrete classes which extend
 /// the kernel class hierarchy, adding methods and fields needed by the
 /// BodyBuilder.
 ///
 /// Instances of these classes may be created using the factory methods in
 /// `ast_factory.dart`.
@@ skipping 405 matching lines @@
     return inferrer.inferMethodInvocation(
         typeContext,
         typeNeeded,
         fileOffset,
         receiver,
         name,
         _getExplicitTypeArguments(arguments),
         _forEachArgument(arguments), (types) {
       arguments.types.clear();
       arguments.types.addAll(types);
+    }, (target) {
+      if (!inferrer.strongMode) {
+        // Our non-strong golden files currently don't include interface
+        // targets, so we can't store the interface target without causing tests
+        // to fail.  TODO(paulberry): fix this.
+        return;
+      }
+      interfaceTarget = target;
     });
   }
 }
 
 /// Shadow object for [Not].
 class KernelNot extends Not implements KernelExpression {
   KernelNot(Expression operand) : super(operand);
 
   @override
   DartType _inferExpression(
@@ skipping 510 matching lines @@
       : super(variable, value);
 
   @override
   DartType _inferExpression(
       KernelTypeInferrer inferrer, DartType typeContext, bool typeNeeded) {
     var variable = this.variable as KernelVariableDeclaration;
     return inferrer.inferVariableSet(
         typeContext, typeNeeded, variable._declaredType, value);
   }
 }