Merge pull request #3797 from retronym/topic/exhaust-compound

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

3 files changed, 45 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
diff --git a/test/files/neg/virtpatmat_exhaust_compound.flags b/test/files/neg/virtpatmat_exhaust_compound.flags
new file mode 100644
index 0000000000..85d8eb2ba2
--- /dev/null
+++ b/test/files/neg/virtpatmat_exhaust_compound.flags
@@ -0,0 +1 @@
+-Xfatal-warnings
diff --git a/test/files/neg/virtpatmat_exhaust_compound.scala b/test/files/neg/virtpatmat_exhaust_compound.scala
new file mode 100644
index 0000000000..386c7af98d
--- /dev/null
+++ b/test/files/neg/virtpatmat_exhaust_compound.scala
@@ -0,0 +1,29 @@
+sealed trait Base
+case object O1 extends Base
+case object O2 extends Base {
+  def foo: Int = 0
+}
+
+sealed trait Base2
+case object O3 extends Base2
+
+case object O4 extends Base with Base2
+
+object Test {
+  val a /*: Product with Serialiable with Base */ = if (true) O1 else O2
+  a match {
+    case null =>
+  }
+
+  def t1(a: Product with Base with Base2) = a match {
+    case null => // O1..O3 should *not* be possible here
+  }
+
+  def t2(a: Product with Base { def foo: Int }) = a match {
+    case null => // O2 in the domain
+  }
+
+  def t3(a: Product with Base { def bar: Int }) = a match {
+    case null => // nothing in the domain
+  }
+}