Adds isDefinedAt to Function1. As a consequence,

code that mixes in PartialFunction now have to
define isDefinedAt as override.

Fixes #2225.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/library/scala/Function1.scala b/src/library/scala/Function1.scala
index 7cfd32304e..80fe7ad1b6 100644
--- a/src/library/scala/Function1.scala
+++ b/src/library/scala/Function1.scala
@@ -47,4 +47,10 @@ trait Function1[-T1, +R] extends AnyRef { self =>
    */
   def andThen[A](g: R => A): T1 => A = { x => g(apply(x)) }
 
+  /** Checks if a value is contained in the functions domain.
+   *
+   *  @param  x   the value to test
+   *  @return true, iff <code>x</code> is in the domain of this function.
+   */
+  def isDefinedAt(x: T1): Boolean = true
 }