revert add isBetween

Author: bishabosha

compiler/src/dotty/tools/dotc/config/SourceVersion.scala

@@ -17,10 +17,6 @@ enum SourceVersion:
 
   def isAtLeast(v: SourceVersion) = stable.ordinal >= v.ordinal
 
-  def isBetween(low: SourceVersion, high: SourceVersion): Boolean =
-    require(low.ordinal < high.ordinal)
-    isAtLeast(low) && stable.ordinal <= high.ordinal
-
 object SourceVersion extends Property.Key[SourceVersion]:
   def defaultSourceVersion = `3.2`
 

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

@@ -1620,8 +1620,8 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
               case Some(checkMode) if !sel.tpe.hasAnnotation(defn.UncheckedAnnot) =>
                 val isPatDef = checkMode == desugar.MatchCheck.IrrefutablePatDef
                 if !checkIrrefutable(sel, pat, isPatDef)
+                  && sourceVersion.isAtLeast(`3.2`)
                   && sourceVersion.isMigrating
-                  && sourceVersion.isBetween(`3.2`, `future`)
                 then
                   if isPatDef then uncheckedBrackets(tree.selector) match
                     case None =>