fix #26812, function types should support the call method

pkg/analyzer/test/src/task/strong/checker_test.dart

 // Copyright (c) 2015, 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 analyzer.test.src.task.strong.checker_test;
 
 import '../../../reflective_tests.dart';
 import 'strong_test_helper.dart';
 
 void main() {
@@ skipping 95 matching lines @@
   p = c == y;
 
   a = a[b];
   a = a[/*info:DYNAMIC_CAST*/c];
   c = (/*info:DYNAMIC_INVOKE*/c[b]);
   a[/*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/y];
 }
 ''');
   }
 
+  void test_callMethodOnFunctions() {
+    checkFile(r'''
+void f(int x) => print(x);
+main() {
+  f.call(/*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/'hi');
+}
+    ''');
+  }
+
   void test_castsInConditions() {
     checkFile('''
 main() {
   bool b = true;
   num x = b ? 1 : 2.3;
   int y = /*info:ASSIGNMENT_CAST*/b ? 1 : 2.3;
   String z = !b ? "hello" : null;
   z = b ? null : "hello";
 }
 ''');
@@ skipping 3544 matching lines @@
     // Regression test for https://github.com/dart-lang/sdk/issues/25069
     checkFile('''
 typedef int Foo();
 void foo() {}
 void main () {
   Foo x = /*error:INVALID_ASSIGNMENT,info:USE_OF_VOID_RESULT*/foo();
 }
 ''');
   }
 }