Backport "Type desugared transparent inline def unapply call in the correct mode" to LTS (#21049)

Backports #20108 to the LTS branch.

PR submitted by the release tooling.
[skip ci]

Author: WojciechMazur

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

@@ -1413,7 +1413,8 @@ trait Applications extends Compatibility {
             report.error(em"Structural unapply is not supported", unapplyFn.srcPos)
             (unapplyFn, unapplyAppCall)
           case Apply(fn, `dummyArg` :: Nil) =>
-            val inlinedUnapplyFn = Inlines.inlinedUnapplyFun(fn)
+            val inlinedUnapplyFn = withoutMode(Mode.Pattern):
+              Inlines.inlinedUnapplyFun(fn)
             (inlinedUnapplyFn, inlinedUnapplyFn.appliedToArgs(`dummyArg` :: Nil))
           case Apply(fn, args) =>
             val (fn1, app) = rec(fn)

tests/pos/i20107.scala

@@ -0,0 +1,6 @@
+object foo:
+	transparent inline def unapply[F](e: F): Option[F] = Some(e.asInstanceOf[F])
+
+class A:
+  def test(x: Int) = x match
+    case foo(e) => e