Don't visit named argument labels when computing constant dependencies.

pkg/analyzer/test/generated/non_error_resolver_test.dart

 // Copyright (c) 2014, 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 engine.non_error_resolver_test;
 
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
@@ skipping 972 matching lines @@
     Source source = addSource(r'''
 class A {
   static x() {}
   static set x(int p) {}
 }''');
     resolve(source);
     assertNoErrors(source);
     verify([source]);
   }
 
+  void test_const_constructor_with_named_generic_parameter() {
+    Source source = addSource('''
+class C<T> {
+  const C({T t});
+}
+const c = const C(t: 1);
+''');
+    resolve(source);
+    assertNoErrors(source);
+    verify([source]);
+  }
+
   void test_const_dynamic() {
     Source source = addSource('''
 const Type d = dynamic;
 ''');
     resolve(source);
     assertNoErrors(source);
     verify([source]);
   }
 
   void test_constConstructorWithNonConstSuper_explicit() {
@@ skipping 4547 matching lines @@
     reset();
   }
 
   void _check_wrongNumberOfParametersForOperator1(String name) {
     _check_wrongNumberOfParametersForOperator(name, "a");
   }
 
   CompilationUnit _getResolvedLibraryUnit(Source source) =>
       analysisContext.getResolvedCompilationUnit2(source, source);
 }