List.unmodifiable

tool/input_sdk/lib/internal/list.dart

 // Copyright (c) 2013, 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.
 
 part of dart._internal;
 
 /**
  * Mixin that throws on the length changing operations of [List].
  *
  * Intended to mix-in on top of [ListMixin] for fixed-length lists.
@@ skipping 343 matching lines @@
  *
  * For internal use only.
  * Only works on growable lists as created by `[]` or `new List()`.
  * May throw on any other list.
  *
  * The operation is efficient. It doesn't copy the elements, but converts
  * the existing list directly to a fixed length list.
  * That means that it is a destructive conversion.
  * The original list should not be used afterwards.
  *
- * The returned list may be the same list as the orginal,
+ * The returned list may be the same list as the original,
  * or it may be a different list (according to [identical]).
  * The original list may have changed type to be a fixed list,
  * or become empty or been otherwise modified.
  * It will still be a valid object, so references to it will not, e.g., crash
  * the runtime if accessed, but no promises are made wrt. its contents.
  *
  * This unspecified behavior is the reason the function is not exposed to
  * users. We allow the underlying implementation to make the most efficient
  * conversion, at the cost of leaving the original list in an unspecified
  * state.
  */
+// TODO(sra): Find a way to declare this as (List<E>) -> List<E> without passing
+// a type parameter.
 external List makeListFixedLength(List growableList);

[vsm, 2016/05/02 23:56:12]

Make this generic?
List/*<T>*/ makeListFixedLength/*<T>*/(List/*<T>*/ growableList);

This should get rid of the cast in the generated code (although DDC will pass
the type param).

+
+/**
+ * Converts a fixed-length list to an unmodifiable list.
+ *
+ * For internal use only.
+ * Only works for core fixed-length lists as created by `new List(length)`,
+ * or as returned by [makeListFixedLength].
+ *
+ * The operation is efficient. It doesn't copy the elements, but converts
+ * the existing list directly to a fixed length list.
+ * That means that it is a destructive conversion.
+ * The original list should not be used afterwards.
+ *
+ * The unmodifiable list type is similar to the one used by const lists.
+ */
+// TODO(sra): Find a way to declare this as (List<E>) -> List<E> without passing
+// a type parameter.
+external List makeFixedListUnmodifiable(List fixedLengthList);

[vsm, 2016/05/02 23:56:12]

Ditto?