Implement new optional parameters syntax in the vm (issue 4290).

tests/language/positional_parameters_type_test.dart

Index: tests/language/positional_parameters_type_test.dart
===================================================================
--- tests/language/positional_parameters_type_test.dart	(revision 0)
+++ tests/language/positional_parameters_type_test.dart	(revision 0)
@@ -0,0 +1,53 @@
+// 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.
+// VMOptions=--enable_type_checks
+//
+// Dart test program for testing optional parameters in type tests.
+
+// TODO(regis): The expected signatures below will change once we run this test
+// with --reject_named_argument_as_positional which is still too early to do at
+// this time.
+
+class NamedParametersTypeTest {
+  static int testMain() {
+    int result = 0;
+    Function anyFunction;
+    void acceptFunNumOptBool(void funNumOptBool(num n, [bool b])) { };
+    void funNum(num n) { };
+    void funNumBool(num n, bool b) { };
+    void funNumOptBool(num n, [bool b = true]) { };
+    void funNumOptBoolX(num n, [bool x = true]) { };
+    anyFunction = funNum;  // No error.
+    anyFunction = funNumBool;  // No error.
+    anyFunction = funNumOptBool;  // No error.
+    anyFunction = funNumOptBoolX;  // No error.
+    acceptFunNumOptBool(funNumOptBool);  // No error.
+    try {
+      acceptFunNumOptBool(funNum);  // No static type warning.
+    } on TypeError catch (error) {
+      result += 1;
+      Expect.stringEquals("(num, [b: bool]) => void", error.dstType);
+      Expect.stringEquals("(num) => void", error.srcType);
+    }
+    try {
+      acceptFunNumOptBool(funNumBool);  /// static type warning
+    } on TypeError catch (error) {
+      result += 10;
+      Expect.stringEquals("(num, [b: bool]) => void", error.dstType);
+      Expect.stringEquals("(num, bool) => void", error.srcType);
+    }
+    try {
+      acceptFunNumOptBool(funNumOptBoolX);  /// static type warning
+    } on TypeError catch (error) {
+      result += 100;
+      Expect.stringEquals("(num, [b: bool]) => void", error.dstType);
+      Expect.stringEquals("(num, [x: bool]) => void", error.srcType);
+    }
+    return result;
+  }
+}
+
+main() {
+  Expect.equals(111, NamedParametersTypeTest.testMain());
+}