Merge pull request #2737 from retronym/ticket/7669

SI-7669 Fix exhaustivity warnings for recursive ADTs.

5 files changed, 23 insertions, 2 deletions

diff --git a/test/files/neg/exhausting.check b/test/files/neg/exhausting.check
index c573eb3e15..619849693c 100644
--- a/test/files/neg/exhausting.check
+++ b/test/files/neg/exhausting.check
@@ -1,5 +1,5 @@
 exhausting.scala:21: warning: match may not be exhaustive.
-It would fail on the following input: List(_, _, _)
+It would fail on the following inputs: List(_), List(_, _, _)
   def fail1[T](xs: List[T]) = xs match {
                               ^
 exhausting.scala:27: warning: match may not be exhaustive.
diff --git a/test/files/neg/exhausting.scala b/test/files/neg/exhausting.scala
index 5554ee2671..01c34f7039 100644
--- a/test/files/neg/exhausting.scala
+++ b/test/files/neg/exhausting.scala
@@ -17,7 +17,7 @@ object Test {
     case (_: Foo[_], _: Foo[_]) => ()
   }
 
-  // fails for: ::(_, ::(_, ::(_, _)))
+  // fails for: ::(_, Nil), ::(_, ::(_, ::(_, _))), ...
   def fail1[T](xs: List[T]) = xs match {
     case Nil            => "ok"
     case x :: y :: Nil  => "ok"
diff --git a/test/files/neg/t7669.check b/test/files/neg/t7669.check
new file mode 100644
index 0000000000..c090ed18ce
--- /dev/null
+++ b/test/files/neg/t7669.check
@@ -0,0 +1,7 @@
+t7669.scala:9: warning: match may not be exhaustive.
+It would fail on the following input: NotHandled(_)
+  def exhausto(expr: Expr): Unit = expr match {
+                                   ^
+error: No warnings can be incurred under -Xfatal-warnings.
+one warning found
+one error found
diff --git a/test/files/neg/t7669.flags b/test/files/neg/t7669.flags
new file mode 100644
index 0000000000..85d8eb2ba2
--- /dev/null
+++ b/test/files/neg/t7669.flags
@@ -0,0 +1 @@
+-Xfatal-warnings
diff --git a/test/files/neg/t7669.scala b/test/files/neg/t7669.scala
new file mode 100644
index 0000000000..12441ec056
--- /dev/null
+++ b/test/files/neg/t7669.scala
@@ -0,0 +1,13 @@
+object Test {
+
+  sealed abstract class Expr
+  // Change type of `arg` to `Any` and the exhaustiveness warning
+  // is issued below
+  case class Op(arg: Expr) extends Expr
+  case class NotHandled(num: Double) extends Expr
+
+  def exhausto(expr: Expr): Unit = expr match {
+    case Op(Op(_)) =>
+    case Op(_) =>
+  }
+}