Fix some type applies not being mapped to proxies correctly

Author: jchyb

compiler/src/dotty/tools/dotc/inlines/Inliner.scala

@@ -570,7 +570,7 @@ class Inliner(val call: tpd.Tree)(using Context):
           // LambdaTypeTree parameters also have the inlineMethod as owner. C.f. i13460.scala.
         && !paramProxy.contains(tpe) =>
       paramBinding.get(tpe.name) match
-        case Some(bound) => paramProxy(tpe) = bound
+        case Some(bound) => paramProxy(tpe) = mapOpaques.typeMap(bound)
         case _ =>  // can happen for params bound by type-lambda trees.
 
       // The widened type may contain param types too (see tests/pos/i12379a.scala)

tests/pos/i22974c.scala

@@ -0,0 +1,18 @@
+object other:
+  sealed abstract class Absent
+  case object Absent extends Absent
+  case class PresentAbsent(val depth: Int)
+  opaque type Present[+A] = A | PresentAbsent
+  opaque type Maybe[+A] >: (Absent | Present[A]) = Absent | Present[A]
+
+  extension [A](self: Maybe[A]) {
+    inline def flatten[B]: Maybe[B] = if self.isEmpty then Absent else ???
+    def isEmpty: Boolean = self.isInstanceOf[Absent]
+  }
+
+class Test {
+  def main(): Unit =
+    import other.Maybe
+    val res: Maybe[Maybe[Int]] = ???
+    res.flatten
+}