Avoid weird Ranges of TypeBounds??

Author: dwijnand

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

@@ -5886,14 +5886,18 @@ object Types {
             if (distributeArgs(args, tp.tyconTypeParams))
               range(tp.derivedAppliedType(tycon, loBuf.toList),
                     tp.derivedAppliedType(tycon, hiBuf.toList))
-            else if tycon.isLambdaSub then
+            else if tycon.isLambdaSub || args.exists(isRangeOfNonTermTypes) then
               range(defn.NothingType, defn.AnyType)
             else
               // See lampepfl/dotty#14152
               range(defn.NothingType, tp.derivedAppliedType(tycon, args.map(rangeToBounds)))
           else tp.derivedAppliedType(tycon, args)
       }
 
+    private def isRangeOfNonTermTypes(tp: Type): Boolean = tp match
+      case Range(lo, hi) => !lo.isInstanceOf[TermType] || !hi.isInstanceOf[TermType]
+      case _             => false
+
     override protected def derivedAndType(tp: AndType, tp1: Type, tp2: Type): Type =
       if (isRange(tp1) || isRange(tp2)) range(lower(tp1) & lower(tp2), upper(tp1) & upper(tp2))
       else tp.derivedAndType(tp1, tp2)