Tighter pattern matching hits the street.

is final and does not conform to the pattern, it will no longer compile.
See all the exciting things you can no longer do:

  "bob".reverse match { case Seq('b', 'o', 'b') => true } // denied!
  "bob".toArray match { case Seq('b', 'o', 'b') => true } // rejected!
  final class Dunk
  def f3(x: Dunk) = x match { case Seq('b', 'o', 'b') => true } // uh-uh!

And so forth.  Review by odersky.

1 files changed, 6 insertions, 1 deletions

diff --git a/test/files/neg/bug1878.check b/test/files/neg/bug1878.check
index 5484d675af..f760781fa0 100644
--- a/test/files/neg/bug1878.check
+++ b/test/files/neg/bug1878.check
@@ -1,10 +1,15 @@
 bug1878.scala:3: error: _* may only come last
   val err1 = "" match { case Seq(f @ _*, ',') => f }
                                  ^
+bug1878.scala:3: error: scrutinee is incompatible with pattern type;
+ found   : Seq[A]
+ required: java.lang.String
+  val err1 = "" match { case Seq(f @ _*, ',') => f }
+                                ^
 bug1878.scala:9: error: _* may only come last
   val List(List(_*, arg2), _) = List(List(1,2,3), List(4,5,6))
                  ^
 bug1878.scala:13: error: _* may only come last
     case <p> { _* } </p> =>
                 ^
-three errors found
+four errors found