Merge pull request scala#2096 from ViniciusMiana/SI-6370

SI-6370 changed ListMap apply0 method to produce correct error message

Author: JamesIry

src/library/scala/collection/immutable/ListMap.scala

@@ -156,8 +156,12 @@ extends AbstractMap[A, B]
      *  @return     the value associated with the given key.
      */
     override def apply(k: A): B1 = apply0(this, k)
-
-    @tailrec private def apply0(cur: ListMap[A, B1], k: A): B1 = if (k == cur.key) cur.value else apply0(cur.tail, k)
+ 
+    
+    @tailrec private def apply0(cur: ListMap[A, B1], k: A): B1 = 
+      if (cur.isEmpty) throw new NoSuchElementException("key not found: "+k)
+      else if (k == cur.key) cur.value
+      else apply0(cur.tail, k)  
 
     /** Checks if this map maps `key` to a value and return the
      *  value if it exists.

test/files/run/t6370.scala

@@ -0,0 +1,12 @@
+object Test {
+
+  def main(args: Array[String]): Unit = {
+      val m = collection.immutable.ListMap( "x" -> 1 )
+      try {
+         m("y")
+      } catch {
+         case e : NoSuchElementException => assert(e.getMessage() == "key not found: y")
+      }
+
+  }
+}