Fix vector pattern matching. Closes #6909.

src/test/run-pass/vec-matching-autoslice.rs

@@ -1,22 +1,22 @@
 pub fn main() {
     let x = @[1, 2, 3];
     match x {
-        [2, .._] => ::std::util::unreachable(),
+        [2, .._] => fail!(),
         [1, ..tail] => {
             assert_eq!(tail, [2, 3]);
         }
-        [_] => ::std::util::unreachable(),
-        [] => ::std::util::unreachable()
+        [_] => fail!(),
+        [] => fail!()
     }
 
     let y = (~[(1, true), (2, false)], 0.5);
     match y {
-        ([_, _, _], 0.5) => ::std::util::unreachable(),
+        ([_, _, _], 0.5) => fail!(),
         ([(1, a), (b, false), ..tail], _) => {
             assert_eq!(a, true);
             assert_eq!(b, 2);
             assert!(tail.is_empty());
         }
-        ([..tail], _) => ::std::util::unreachable()
+        ([..tail], _) => fail!()
     }
 }

src/test/run-pass/vec-matching.rs

@@ -1,14 +1,14 @@
 fn a() {
     let x = [1];
     match x {
-        [_, _, _, _, _, .._] => ::std::util::unreachable(),
-        [.._, _, _, _, _] => ::std::util::unreachable(),
-        [_, .._, _, _] => ::std::util::unreachable(),
-        [_, _] => ::std::util::unreachable(),
+        [_, _, _, _, _, .._] => fail!(),
+        [.._, _, _, _, _] => fail!(),
+        [_, .._, _, _] => fail!(),
+        [_, _] => fail!(),
         [a] => {
             assert_eq!(a, 1);
         }
-        [] => ::std::util::unreachable()
+        [] => fail!()
     }
 }
 
@@ -48,7 +48,28 @@ fn b() {
     }
 }
 
+fn c() {
+    let x = [1];
+    match x {
+        [2, .. _] => fail!(),
+        [.. _] => ()
+    }
+}
+
+fn d() {
+    let x = [1, 2, 3];
+    let branch = match x {
+        [1, 1, .. _] => 0,
+        [1, 2, 3, .. _] => 1,
+        [1, 2, .. _] => 2,
+        _ => 3
+    };
+    assert_eq!(branch, 1);
+}
+
 pub fn main() {
     a();
     b();
+    c();
+    d();
 }