Fix corner cases of type inference with implicit references to `.call`.

pkg/analyzer/test/src/task/strong/front_end_inference_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 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
@@ skipping 343 matching lines @@
             _recordType(parameter.offset, type.parameters[i].type);
           }
         }
       }
     }
   }
 
   @override
   visitFunctionExpressionInvocation(FunctionExpressionInvocation node) {
     super.visitFunctionExpressionInvocation(node);
+    var receiverType = node.function.staticType;
+    if (receiverType is InterfaceType) {
+      // This is a hack since analyzer doesn't record .call targets
+      var target = receiverType.element.lookUpMethod('call', null) ??
+          receiverType.element.lookUpGetter('call', null);
+      if (target != null) {
+        _recordTarget(node.argumentList.offset, target);
+      }
+    }
     if (node.typeArguments == null) {
       var inferredTypeArguments = _getInferredFunctionTypeArguments(
               node.function.staticType,
               node.staticInvokeType,
               node.typeArguments)
           .toList();
       if (inferredTypeArguments.isNotEmpty) {
         _recordTypeArguments(node.argumentList.offset, inferredTypeArguments);
       }
     }
@@ skipping 162 matching lines @@
 
   /// Based on DDC code generator's `_recoverTypeArguments`
   Iterable<DartType> _recoverTypeArguments(FunctionType g, FunctionType f) {
     assert(identical(g.element, f.element));
     assert(g.typeFormals.isNotEmpty && f.typeFormals.isEmpty);
     assert(g.typeFormals.length + g.typeArguments.length ==
         f.typeArguments.length);
     return f.typeArguments.skip(g.typeArguments.length);
   }
 }