- Do not pass optional positional parameters with a name.

tests/compiler/dart2js_native/native_call_arity1_frog_test.dart

 // Copyright (c) 2011, 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.
 
 // Test that native methods with unnamed* optional arguments are called with the
 // number of arguments in the call site.  This is necessary because native
 // methods can dispatch on the number of arguments.  Passing null or undefined
 // as the last argument is not the same as passing one fewer argument.
 //
 // * Named arguments are passed in the correct position, so require preceding
@@ skipping 33 matching lines @@
   Expect.throws(() => a.foo());
   Expect.equals(1, a.foo(10));
   Expect.throws(() => a.foo(10, 20));
   Expect.throws(() => a.foo(10, 20, 30));
 
   Expect.equals(0, b.foo());
   Expect.equals(1, b.foo(10));
   Expect.equals(2, b.foo(10, 20));
   Expect.equals(3, b.foo(10, 20, 30));
 
-  Expect.equals(1, b.foo(x: 10));   // 1 = x
-  Expect.equals(2, b.foo(y: 20));   // 2 = x, y
-  Expect.equals(3, b.foo(z: 30));   // 3 = x, y, z
   Expect.throws(() => b.foo(10, 20, 30, 40));
 }
 
 testStaticContext() {
   A a = makeA();
   B b = makeB();
 
   Expect.throws(() => a.foo());
   Expect.equals(1, a.foo(10));
   Expect.throws(() => a.foo(10, 20));
   Expect.throws(() => a.foo(10, 20, 30));
 
   Expect.equals(0, b.foo());
   Expect.equals(1, b.foo(10));
   Expect.equals(2, b.foo(10, 20));
   Expect.equals(3, b.foo(10, 20, 30));
 
-  Expect.equals(1, b.foo(x: 10));
-  Expect.equals(2, b.foo(y: 20));
-  Expect.equals(3, b.foo(z: 30));
   Expect.throws(() => b.foo(10, 20, 30, 40));
 }
 
 main() {
   setup();
   testDynamicContext();
   testStaticContext();
 }