Partial revert of pattern matching message kinds

Author: odersky

compiler/src/dotty/tools/dotc/reporting/messages.scala

@@ -806,7 +806,8 @@ object messages {
   }
 
   class PatternMatchExhaustivity(uncoveredFn: => String)(implicit ctx: Context)
-  extends PatternMatchMsg(PatternMatchExhaustivityID) {
+  extends Message(PatternMatchExhaustivityID) {
+    val kind = "Pattern Match Exhaustivity"
     lazy val uncovered = uncoveredFn
     lazy val msg: String =
       em"""|${hl("match")} may not be exhaustive.
@@ -834,7 +835,8 @@ object messages {
   }
 
   class MatchCaseUnreachable()(implicit ctx: Context)
-  extends PatternMatchMsg(MatchCaseUnreachableID) {
+  extends Message(MatchCaseUnreachableID) {
+    val kind = "Match case Unreachable"
     lazy val msg: String = "Unreachable case"
     lazy val explanation: String = ""
   }

tests/patmat/i4225b.check

@@ -1 +1 @@
-10: Only null matched
+10: Pattern Match

tests/patmat/null.check

@@ -1,4 +1,4 @@
 6: Match case Unreachable
-13: Only null matched
+13: Pattern Match
 18: Match case Unreachable
-20: Only null matched
+20: Pattern Match

tests/patmat/t4661.check

@@ -9,7 +9,7 @@
 37: Match case Unreachable
 38: Match case Unreachable
 39: Match case Unreachable
-40: Only null matched
+40: Pattern Match
 46: Match case Unreachable
 52: Match case Unreachable
-59: Only null matched
+59: Pattern Match