SI-8647 Used immutable scheme for mutable.BitSet to resolve canBuildFrom

mutable.BitSet had a conflict between its own implicit canBuildFrom and the one inherited from SortedSetFactory in mutable.SortedSet.

The immutable hierarchy already had a workaround; this just copies it on the mutable side.

Test written to verify compilation.

1 files changed, 7 insertions, 0 deletions

diff --git a/test/junit/scala/collection/mutable/BitSetTest.scala b/test/junit/scala/collection/mutable/BitSetTest.scala
index d56cc45601..e832194989 100644
--- a/test/junit/scala/collection/mutable/BitSetTest.scala
+++ b/test/junit/scala/collection/mutable/BitSetTest.scala
@@ -28,4 +28,11 @@ class BitSetTest {
     littleBitSet &= bigBitSet
     assert(littleBitSet.toBitMask.length < bigBitSet.toBitMask.length, "Needlessly extended the size of bitset on &=")
   }
+
+  @Test def test_SI8647() {
+    val bs = BitSet()
+    bs.map(_ + 1)    // Just needs to compile
+    val xs = bs: SortedSet[Int]
+    xs.map(_ + 1)    // Also should compile (did before)
+  }
 }