Reject all non-type refinements

Author: milessabin

compiler/src/dotty/tools/dotc/typer/Implicits.scala

@@ -904,8 +904,8 @@ trait Implicits { self: Typer =>
   private def checkFormal(formal: Type)(implicit ctx: Context): Boolean = {
     @tailrec
     def loop(tp: Type): Boolean = tp match {
-      case RefinedType(_, _, _: MethodicType) => false
-      case RefinedType(parent, _, _) => loop(parent)
+      case RefinedType(parent, _, _: TypeBounds) => loop(parent)
+      case RefinedType(_, _, _) => false
       case _ => true
     }
     loop(formal)

tests/neg/mirror-implicit-scope.scala

@@ -11,4 +11,5 @@ object Test {
   val v3 = the[Mirror.Product { type MirroredType = ISB ; def foo: Int }] // error
   val v4 = the[Mirror.Product { type MirroredType = ISB ; def foo(i: Int): Int }] // error
   val v5 = the[Mirror.Product { type MirroredType = ISB ; def foo[T](t: T): T }] // error // error
+  val v6 = the[Mirror.Product { type MirroredType = ISB ; val foo: Int }] // error
 }