Normalize types in compareAtoms

Author: mbovel

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

@@ -1579,21 +1579,17 @@ class TypeComparer(@constructorOnly initctx: Context) extends ConstraintHandling
         finally canCompareAtoms = true
       result
 
-    tp2.atoms match
+    tp2.normalized.atoms match
       case Atoms.Range(lo2, hi2) if canCompareAtoms && canCompare(hi2) =>
-        tp1.atoms match
+        tp1.normalized.atoms match
           case Atoms.Range(lo1, hi1) =>
             if hi1.subsetOf(lo2) || knownSingletons && hi2.size == 1 && hi1 == hi2 then
               Some(verified(true))
             else if !lo1.subsetOf(hi2) then
               Some(verified(false))
             else
               None
-          case Atoms.Unknown =>
-            if knownSingletons then
-              Some(verified(recur(tp1, NothingType)))
-            else
-              None
+          case _ => Some(verified(recur(tp1, NothingType)))
       case _ => None
 
   /** Subtype test for corresponding arguments in `args1`, `args2` according to