SI-8731 warning if @switch is ignored

For matches with two or fewer cases, @switch is ignored. This should
not happen silently.

1 files changed, 15 insertions, 0 deletions

diff --git a/test/files/neg/t8731.scala b/test/files/neg/t8731.scala
new file mode 100644
index 0000000000..d93fe706ad
--- /dev/null
+++ b/test/files/neg/t8731.scala
@@ -0,0 +1,15 @@
+class C {
+  // not a compile-time constant due to return type
+  final val K: Int = 20
+
+  def f(x: Int) = (x: @annotation.switch) match {
+    case K => 0
+    case 2 => 1
+  }
+
+  def g(x: Int) = (x: @annotation.switch) match {
+    case K => 0
+    case 2 => 1
+    case 3 => 2
+  }
+}