Issue 991: Missing compiler errors for uninitialized final fields

tests/language/src/ConstructorDuplicateInitializersTest.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.
+// Check that initializers are not duplicated
+
+
+class Class {
+  Class(var v)
+    : field_ = v
+    , field_ = 2  /// 01: compile-time error

[ahe, 2012/01/03 22:57:12]

I suggest adding a comment above explaining what the error is.

[codefu, 2012/01/04 15:18:49]

Done.

+  ;
+  Class.field(this.field_)
+    : field_ = 2  /// 02: compile-time error

[ahe, 2012/01/03 22:57:12]

Ditto.

[codefu, 2012/01/04 15:18:49]

Done.

+  ;
+  final field_;
+}
+
+main() {
+  new Class(42);
+  new Class.field(42);
+}