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

sdk/lib/collection/hash_map.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.collection;
 
 /** Default function for equality comparison in customized HashMaps */
 bool _defaultEquals(a, b) => a == b;
 /** Default function for hash-code computation in customized HashMaps */
 int _defaultHashCode(a) => a.hashCode;
 
 /** Type of custom equality function */
 typedef bool _Equality<K>(K a, K b);
 /** Type of custom hash code function. */
 typedef int _Hasher<K>(K object);
 
 /**
  * A hash-table based implementation of [Map].
  *
- * The keys of a `HashMap` must have consistent [Object.operator==]
+ * The keys of a `HashMap` must have consistent [Object.==]
  * and [Object.hashCode] implementations. This means that the `==` operator
  * must define a stable equivalence relation on the keys (reflexive,
  * symmetric, transitive, and consistent over time), and that `hashCode`
  * must be the same for objects that are considered equal by `==`.
  *
  * The map allows `null` as a key.
  *
  * Iterating the map's keys, values or entries (through [forEach])
  * may happen in any order.
  * The iteration order only changes when the map is modified.
  * Values are iterated in the same order as their associated keys,
  * so iterating the [keys] and [values] in parallel
  * will give matching key and value pairs.
  */
 abstract class HashMap<K, V> implements Map<K, V> {
   /**
    * Creates an unordered hash-table based [Map].
    *
    * The created map is not ordered in any way. When iterating the keys or
    * values, the iteration order is unspecified except that it will stay the
    * same as long as the map isn't changed.
    *
    * If [equals] is provided, it is used to compare the keys in the table with
-   * new keys. If [equals] is omitted, the key's own [Object.operator==] is used
+   * new keys. If [equals] is omitted, the key's own [Object.==] is used
    * instead.
    *
    * Similar, if [hashCode] is provided, it is used to produce a hash value
    * for keys in order to place them in the hash table. If it is omitted, the
    * key's own [Object.hashCode] is used.
    *
-   * If using methods like [operator[]], [remove] and [containsKey] together
+   * If using methods like [[]], [remove] and [containsKey] together
    * with a custom equality and hashcode, an extra `isValidKey` function
    * can be supplied. This function is called before calling [equals] or
    * [hashCode] with an argument that may not be a [K] instance, and if the
    * call returns false, the key is assumed to not be in the set.
    * The [isValidKey] function defaults to just testing if the object is a
    * [K] instance.
    *
    * Example:
    *
    *     new HashMap<int,int>(equals: (int a, int b) => (b - a) % 5 == 0,
@@ skipping 74 matching lines @@
    * overwrites the previous value.
    *
    * It is an error if the two [Iterable]s don't have the same length.
    */
   factory HashMap.fromIterables(Iterable<K> keys, Iterable<V> values) {
     HashMap<K, V> map = new HashMap<K, V>();
     Maps._fillMapWithIterables(map, keys, values);
     return map;
   }
 }