fixup checkIrrefutable logic

Author: griggt

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

@@ -814,10 +814,11 @@ trait Checking {
     def check(pat: Tree, pt: Type): Boolean = (pt <:< pat.tpe) || fail(pat, pt)
 
     def recur(pat: Tree, pt: Type): Boolean =
-      !(sourceVersion.isAtLeast(`3.2`) && !sourceVersion.isMigrating) ||
-      pt.hasAnnotation(defn.UncheckedAnnot) || {
+      sourceVersion.ordinal < `3.2`.ordinal
+      || pt.hasAnnotation(defn.UncheckedAnnot)
+      || {
         patmatch.println(i"check irrefutable $pat: ${pat.tpe} against $pt")
-        pat match {
+        pat match
           case Bind(_, pat1) =>
             recur(pat1, pt)
           case UnApply(fn, _, pats) =>
@@ -835,7 +836,6 @@ trait Checking {
           case _ =>
             check(pat, pt)
         }
-      }
 
     recur(pat, pt)
   }