Test with difficult to parse formal parameters.

tests/language/src/ClosuresWithComplexParamsTest.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.
+
+// Tests for parsing closures with complex parameter types.
+
+main() {
+  test1();
+  test2();
+  test3();
+}
+
+class Pair<A, B> {
+  final A fst;
+  final B snd;
+  Pair(A this.fst, B this.snd);
+}
+
+test1() {
+  // Closures with nested parameterized types.
+  var cdar1 = (Pair<int, Pair<int, int>> pr) => pr.snd.fst;
+  var cdar2 = (Pair<int, Pair<int, int> > pr) => pr.snd.fst;
+
+  var e = new Pair<int, Pair<int, int>>(100, new Pair<int, int>(200, 300));
+
+  Expect.equals(200, cdar1(e));
+  Expect.equals(200, cdar2(e));
+}
+
+test2() {
+  // Closures with nested parameterized types in optional position
+  var cdar1 = ([Pair<int, Pair<int, int>> pr = null]) => pr.snd.fst;
+  var cdar2 = ([Pair<int, Pair<int, int> > pr = null]) => pr.snd.fst;
+
+  var e = new Pair<int, Pair<int, int>>(100, new Pair<int, int>(200, 300));
+
+  Expect.equals(200, cdar1(e));
+  Expect.equals(200, cdar2(e));
+}
+
+test3() {
+  // Closures with nested parameterized types.
+  var f1 = (Pair<int, Pair<int, int>> pr) => pr.snd.fst + 1;
+  var f2 = (Pair<int, Pair<int, int> > pr) => pr.snd.fst + 2;
+
+  // Closures with function type with nested parameterized types.
+  var ap1 = (f(Pair<int, Pair<int, int>> pr), Pair<int, Pair<int, int>> pr)
+                 => f(pr) * 10;
+  var ap2 = (f(Pair<int, Pair<int, int> > pr), Pair<int, Pair<int, int> > pr)
+                 => f(pr) * 100;
+
+  var e = new Pair<int, Pair<int, int>>(100, new Pair<int, int>(200, 300));
+
+  Expect.equals(2010, ap1(f1, e));
+  Expect.equals(2020, ap1(f2, e));
+  Expect.equals(20100, ap2(f1, e));
+  Expect.equals(20200, ap2(f2, e));
+}