Adds isDefinedAt to Function1. As a consequence,

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

Fixes #2225.

5 files changed, 15 insertions, 16 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
 }
diff --git a/src/library/scala/PartialFunction.scala b/src/library/scala/PartialFunction.scala
index 0ba7527976..1eb5f89fa4 100644
--- a/src/library/scala/PartialFunction.scala
+++ b/src/library/scala/PartialFunction.scala
@@ -21,16 +21,9 @@ package scala
  */
 trait PartialFunction[-A, +B] extends AnyRef with (A => B) {
 
-  /** 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: A): Boolean
-
   def orElse[A1 <: A, B1 >: B](that: PartialFunction[A1, B1]) : PartialFunction[A1, B1] =
     new PartialFunction[A1, B1] {
-    def isDefinedAt(x: A1): Boolean =
+    override def isDefinedAt(x: A1): Boolean =
       PartialFunction.this.isDefinedAt(x) || that.isDefinedAt(x)
     def apply(x: A1): B1 =
       if (PartialFunction.this.isDefinedAt(x)) PartialFunction.this.apply(x)
@@ -38,7 +31,7 @@ trait PartialFunction[-A, +B] extends AnyRef with (A => B) {
   }
 
   override def andThen[C](k: B => C) : PartialFunction[A, C] = new PartialFunction[A, C] {
-    def isDefinedAt(x: A): Boolean = PartialFunction.this.isDefinedAt(x)
+    override def isDefinedAt(x: A): Boolean = PartialFunction.this.isDefinedAt(x)
     def apply(x: A): C = k(PartialFunction.this.apply(x))
   }
 }
diff --git a/src/library/scala/collection/MapLike.scala b/src/library/scala/collection/MapLike.scala
index 3b188acab6..8c44c374ca 100644
--- a/src/library/scala/collection/MapLike.scala
+++ b/src/library/scala/collection/MapLike.scala
@@ -122,7 +122,7 @@ self =>
    *  @param key the key
    *  @return    <code>true</code> iff there is a mapping for key in this map
    */
-  def isDefinedAt(key: A) = contains(key)
+  override def isDefinedAt(key: A) = contains(key)
 
   /** @return the keys of this map as a set. */
   def keySet: Set[A] = new DefaultKeySet
diff --git a/src/library/scala/collection/SeqLike.scala b/src/library/scala/collection/SeqLike.scala
index 708764e958..3413cb8a07 100644
--- a/src/library/scala/collection/SeqLike.scala
+++ b/src/library/scala/collection/SeqLike.scala
@@ -109,7 +109,7 @@ object SeqLike {
  *  @version 1.0, 16/07/2003
  *  @since   2.8
  */
-trait SeqLike[+A, +Repr] extends IterableLike[A, Repr] { self =>
+trait SeqLike[+A, +Repr] extends Function[Int, A] with IterableLike[A, Repr] { self =>
 
   override protected[this] def thisCollection: Seq[A] = this.asInstanceOf[Seq[A]]
   override protected[this] def toCollection(repr: Repr): Seq[A] = repr.asInstanceOf[Seq[A]]
@@ -147,7 +147,7 @@ trait SeqLike[+A, +Repr] extends IterableLike[A, Repr] { self =>
 
   /** Is this partial function defined for the index <code>x</code>?
    */
-  def isDefinedAt(x: Int): Boolean = (x >= 0) && (x < length)
+  override def isDefinedAt(x: Int): Boolean = (x >= 0) && (x < length)
 
   /** Returns length of longest segment starting from a start index `from`
    *  such that every element of the segment satisfies predicate `p`.
diff --git a/src/library/scala/util/control/Exception.scala b/src/library/scala/util/control/Exception.scala
index 356b11df51..8add16fb70 100644
--- a/src/library/scala/util/control/Exception.scala
+++ b/src/library/scala/util/control/Exception.scala
@@ -31,7 +31,7 @@ object Exception
   // a Throwable => T and simply rethrow the non-Exceptions.
   implicit def fromExceptionCatcher[T](pf: ExceptionCatcher[T]): Catcher[T] = {
     new PartialFunction[Throwable, T] {
-      def isDefinedAt(x: Throwable) = x match {
+      override def isDefinedAt(x: Throwable) = x match {
         case e: Exception if pf.isDefinedAt(e)  => true
         case _                                  => false
       }
@@ -102,7 +102,7 @@ object Exception
       * but with the supplied apply method replacing the current one. */
     def withApply[U](f: (Throwable) => U): Catch[U] = {
       val pf2 = new PartialFunction[Throwable, U] {
-        def isDefinedAt(x: Throwable) = pf isDefinedAt x
+        override def isDefinedAt(x: Throwable) = pf isDefinedAt x
         def apply(x: Throwable) = f(x)
       }
       new Catch(pf2, fin)
@@ -141,7 +141,7 @@ object Exception
 
   final val nothingCatcher: PartialFunction[Throwable, Nothing] =
     new PartialFunction[Throwable, Nothing] {
-      def isDefinedAt(x: Throwable) = false
+      override def isDefinedAt(x: Throwable) = false
       def apply(x: Throwable) = throw x
     }
 
@@ -209,6 +209,6 @@ object Exception
   private def pfFromExceptions(exceptions: Class[_]*) =
     new PartialFunction[Throwable, Nothing] {
       def apply(x: Throwable) = throw x
-      def isDefinedAt(x: Throwable) = wouldMatch(x, exceptions)
+      override def isDefinedAt(x: Throwable) = wouldMatch(x, exceptions)
     }
 }