Handle corner case correctly

Author: odersky

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

@@ -624,7 +624,7 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling {
    */
   def compareHkApply2(tp1: Type, tp2: HKApply, tycon2: Type, args2: List[Type]): Boolean = {
     val tparams = tycon2.typeParams
-    if (tparams.isEmpty) return false // can happen for ill-typed programs, e.g. neg/tcpoly_overloaded.scala
+    if (tparams.isEmpty) return tp1.isRef(NothingClass) // can happen for ill-typed programs, e.g. neg/tcpoly_overloaded.scala
 
     /** True if `tp1` and `tp2` have compatible type constructors and their
      *  corresponding arguments are subtypes relative to their variance (see `isSubArgs`).