remove workaround for type variable

Author: Linyxus

compiler/src/dotty/tools/dotc/core/GadtConstraint.scala

@@ -362,7 +362,6 @@ final class ProperGadtConstraint private(
                   case tv: TypeVar => tv.origin
                   case null => tp
                 }
-              case tv: TypeVar => if isUpper then defn.AnyType else defn.NothingType
               case tp => tp
 
             loop(tp)

tests/pos/pdgadt-wildcard.scala renamed to tests/neg/pdgadt-wildcard.scala

@@ -3,6 +3,6 @@ case class Inv[X](x: X) extends Expr { type T = X }
 case class Inv2[X](x: X) extends Expr { type T >: X }
 
 def eval(e: Expr): e.T = e match
-  case Inv(x) => x
+  case Inv(x) => x  // limitation // error
   case Inv2(x) => x