SI-8631 Treat `A with Sealed` as enumerable for pattern matching

Enumerate the subtypes of sealed parent types of refinement
types, and filter those that conform to the refinement type.

Such types can crop up easily when LUB-bing case classes which
add `Product with Serializable` to the mix.

1 files changed, 15 insertions, 0 deletions

diff --git a/test/files/neg/virtpatmat_exhaust_compound.check b/test/files/neg/virtpatmat_exhaust_compound.check
new file mode 100644
index 0000000000..72e0340682
--- /dev/null
+++ b/test/files/neg/virtpatmat_exhaust_compound.check
@@ -0,0 +1,15 @@
+virtpatmat_exhaust_compound.scala:14: warning: match may not be exhaustive.
+It would fail on the following inputs: O1, O2, O4
+  a match {
+  ^
+virtpatmat_exhaust_compound.scala:18: warning: match may not be exhaustive.
+It would fail on the following input: O4
+  def t1(a: Product with Base with Base2) = a match {
+                                            ^
+virtpatmat_exhaust_compound.scala:22: warning: match may not be exhaustive.
+It would fail on the following input: O2
+  def t2(a: Product with Base { def foo: Int }) = a match {
+                                                  ^
+error: No warnings can be incurred under -Xfatal-warnings.
+three warnings found
+one error found