Don't use [operator==] to refer to [==] in DartDoc. It doesn't work.

sdk/lib/collection/splay_tree.dart

 // Copyright (c) 2012, 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.collection;
 
 typedef bool _Predicate<T>(T value);
 
 /**
  * A node in a splay tree. It holds the sorting key and the left
@@ skipping 242 matching lines @@
  * Keys of the map are compared using the `compare` function passed in
  * the constructor, both for ordering and for equality.
  * If the map contains only the key `a`, then `map.containsKey(b)`
  * will return `true` if and only if `compare(a, b) == 0`,
  * and the value of `a == b` is not even checked.
  * If the compare function is omitted, the objects are assumed to be
  * [Comparable], and are compared using their [Comparable.compareTo] method.
  * Non-comparable objects (including `null`) will not work as keys
  * in that case.
  *
- * To allow calling [operator[]], [remove] or [containsKey] with objects
+ * To allow calling [[]], [remove] or [containsKey] with objects
  * that are not supported by the `compare` function, an extra `isValidKey`
  * predicate function can be supplied. This function is tested before
  * using the `compare` function on an argument value that may not be a [K]
  * value. If omitted, the `isValidKey` function defaults to testing if the
  * value is a [K].
  */
 class SplayTreeMap<K, V> extends _SplayTree<K, _SplayTreeMapNode<K, V>>
     implements Map<K, V> {
   _SplayTreeMapNode<K, V> _root;
   final _SplayTreeMapNode<K, V> _dummy =
@@ skipping 573 matching lines @@
     return new _SplayTreeNode<E>(node.key)..left = _copyNode(node.left)
                                           ..right = _copyNode(node.right);
   }
 
   void clear() { _clear(); }
 
   Set<E> toSet() => _clone();
 
   String toString() => IterableBase.iterableToFullString(this, '{', '}');
 }