Set.add returns true if item has been added, otherwise false

sdk/lib/core/set.dart

Index: sdk/lib/core/set.dart
diff --git a/sdk/lib/core/set.dart b/sdk/lib/core/set.dart
index 19be402b71fe579abfc4191ea6faa4d3299dfaba..eff0b42c9decb2d5ca966b4420276ccc8dd03a5a 100644
--- a/sdk/lib/core/set.dart
+++ b/sdk/lib/core/set.dart
@@ -53,11 +53,11 @@ abstract class Set<E> extends IterableBase<E> {
   bool contains(Object value);
 
   /**
-   * Adds [value] into the set.
+   * Adds [value] into the set. Returns `true` if [value] was added to the set.

[Lasse Reichstein Nielsen, 2013/10/08 12:35:03]

Put "Returns ..." sentence at the end of the dartdoc as a separate paragraph.

The structure we aim for (more or less, it's more of a guideline than a hard
rule) is:

/**
 * Single sentence description.
 *
 * More elaborate description, if necessary.
 *
 * Meaning of, and restrictions on, parameters. May be intermixed
 * with description above.
 *
 * Result description, starting with "Returns ..".
 *
 * If necessary, exception description starting with "Throws"
 */

    *
-   * The method has no effect if [value] is already in the set.
+   * If [value] already exists, the set is not changed and `false` is returned.
    */
-  void add(E value);
+  bool add(E value);
 
   /**
    * Adds all of [elements] to this Set.