Massively simplified the exhaustiveness checker...

Massively simplified the exhaustiveness checker with no measurable loss
of fidelity. I might be the only one who can be unsurprised by such a
bloody diff: anyone else would rightly say "how on earth..." No review.

1 files changed, 24 insertions, 0 deletions

diff --git a/test/files/neg/exhausting.check b/test/files/neg/exhausting.check
new file mode 100644
index 0000000000..6383a6eaca
--- /dev/null
+++ b/test/files/neg/exhausting.check
@@ -0,0 +1,24 @@
+exhausting.scala:20: error: match is not exhaustive!
+missing combination              *           Nil
+
+  def fail1[T](xs: List[T]) = xs match {
+      ^
+exhausting.scala:24: error: match is not exhaustive!
+missing combination            Nil
+
+  def fail2[T](xs: List[T]) = xs match {
+                              ^
+exhausting.scala:27: error: match is not exhaustive!
+missing combination           Bar3
+
+  def fail3[T](x: Foo[T]) = x match {
+                            ^
+exhausting.scala:31: error: match is not exhaustive!
+missing combination           Bar1          Bar2
+missing combination           Bar1          Bar3
+missing combination           Bar2          Bar1
+missing combination           Bar2          Bar2
+
+  def fail4[T](xx: (Foo[T], Foo[T])) = xx match {
+      ^
+four errors found