Lots of work hardening matching on sequences.

one long-standing bug which actually had a test case testing its
bugginess (which is to say, when I fixed the bug, the test case failed.)
This:

-    def doMatch4(xs:Seq[Char]) = xs match {
-      case Seq(x, y, _*) => x::y::Nil
-      case Seq(x, y, z, w) => List(z,w) // redundant!
-    }

...should never have compiled - which must have been recognized
on some level given the "redundant!" comment, but it never made
it into neg/.

1 files changed, 20 insertions, 0 deletions

diff --git a/test/files/neg/pat_unreachable.scala b/test/files/neg/pat_unreachable.scala
new file mode 100644
index 0000000000..c07be8edf0
--- /dev/null
+++ b/test/files/neg/pat_unreachable.scala
@@ -0,0 +1,20 @@
+
+object Test extends Application {
+  def unreachable1(xs:Seq[Char]) = xs match {
+    case Seq(x, y, _*) => x::y::Nil
+    case Seq(x, y, z, w) => List(z,w) // redundant!
+  }
+  def unreachable2(xs:Seq[Char]) = xs match {
+    case Seq(x, y, _*) => x::y::Nil
+    case Seq(x, y) => List(x, y)
+  }
+
+  def not_unreachable(xs:Seq[Char]) = xs match {
+    case Seq(x, y, _*) => x::y::Nil
+    case Seq(x) => List(x)
+  }
+  def not_unreachable2(xs:Seq[Char]) = xs match {
+    case Seq(x, y) => x::y::Nil
+    case Seq(x, y, z, _*) => List(x,y)
+  }
+}
\ No newline at end of file