diff options
| -rw-r--r-- | src/library/scala/collection/TraversableLike.scala | 2 | ||||
| -rw-r--r-- | test/files/run/t5387.scala | 15 |
2 files changed, 16 insertions, 1 deletions
diff --git a/src/library/scala/collection/TraversableLike.scala b/src/library/scala/collection/TraversableLike.scala index b4813e6341..36d45c0c8a 100644 --- a/src/library/scala/collection/TraversableLike.scala +++ b/src/library/scala/collection/TraversableLike.scala @@ -535,7 +535,7 @@ trait TraversableLike[+A, +Repr] extends HasNewBuilder[A, Repr] val b = newBuilder var go = false for (x <- this) { - if (!p(x)) go = true + if (!go && !p(x)) go = true if (go) b += x } b.result diff --git a/test/files/run/t5387.scala b/test/files/run/t5387.scala new file mode 100644 index 0000000000..5d62a005a9 --- /dev/null +++ b/test/files/run/t5387.scala @@ -0,0 +1,15 @@ +/* + * This tests that the predicate of dropWhile is only evaluated as often as needed, see https://issues.scala-lang.org/browse/SI-5387 + */ +import scala.collection.immutable.ListMap +object Test extends App{ + val subject = ListMap(1->1,2->2,3->3,4->4,5->5) + val result = ListMap(3->3,4->4,5->5) + assert( result == subject.dropWhile{ + case (key, value) => { + assert( key <= 3, "predicate evaluated more often than needed, key "+key ) + key < 3 + } + } + ) +} |