Fixed two problems with annotated types in patterns

Problem 1: The parser did not accept them. It has to accept a "RefinedType" as an ascription,
not a "WithType" (as it did before), or even a "SimpleType" (as speced in the SyntaxSummary).

Problem 2: Annotations are always typed as expressions. The annotations in question were typed
as patterns before.

Tests in Patterns.scala and in the Dotty compiler itself.

1 files changed, 9 insertions, 3 deletions

diff --git a/tests/pos/Patterns.scala b/tests/pos/Patterns.scala
index fbcdc4c30..4470eb232 100644
--- a/tests/pos/Patterns.scala
+++ b/tests/pos/Patterns.scala
@@ -10,17 +10,23 @@ object Patterns {
     case (digit, str) => true
     case _ => false
   }
-  
+
+  (xs: Any) match {
+    case x: Int @unchecked => true
+    case xs: List[Int @ unchecked] => true
+    case _ => false
+  }
+
   def sum(xs: List[Int]): Int = xs match {
     case Nil => 0
     case x :: xs1 => x + sum(xs1)
   }
-  
+
   def len[T](xs: List[T]): Int = xs match {
     case _ :: xs1 => 1 + len(xs1)
     case Nil => 0
   }
-  
+
   final def sameLength[T](xs: List[T], ys: List[T]): Boolean = xs match {
     case _ :: xs1 =>
       ys match {