diff --git a/compiler/src/dotty/tools/dotc/typer/Implicits.scala b/compiler/src/dotty/tools/dotc/typer/Implicits.scala
index f303bfbc5e19..f48963ea04e3 100644
--- a/compiler/src/dotty/tools/dotc/typer/Implicits.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Implicits.scala
@@ -610,6 +610,8 @@ trait ImplicitRunInfo:
         else
           partSeen += t
           t.dealias match
+            case dealias if t ne dealias =>
+              traverse(wildApprox(dealias))
             case t: TypeRef =>
               if isAnchor(t.symbol) then
                 parts += t
diff --git a/tests/neg/i17305.scala b/tests/neg/i17305.scala
new file mode 100644
index 000000000000..f233abf9362e
--- /dev/null
+++ b/tests/neg/i17305.scala
@@ -0,0 +1,36 @@
+trait Wrapper[A1] {
+  def use(a: A1 => Unit): Unit
+}
+
+trait Assertion[A2] {}
+
+def hideTypeInOut[A3](
+    c1: A3
+)(using
+    hider: HideAInOut[A3]
+): Wrapper[hider.Out] = ???
+
+def entryPoint(): Unit = {
+  hideTypeInOut(1L)
+    .use((pair) => myAssert(pair)(someAssertion(2))) // error Assertion[Int] instead of Assertion[Long]
+}
+
+private def myAssert[A4](a: A4)(assertion: Assertion[A4]): Unit = ()
+
+private def someAssertion(i: Int): Assertion[Int] = ???
+
+trait HideAInOut[-A] {
+  type Out
+  def get(left: A): Out
+}
+
+object HideAInOut {
+
+  type Out[HideA, HideB] = HideAInOut[HideA] { type Out = HideB }
+
+  given [GivenA]: HideAInOut.Out[GivenA, GivenA] =
+    new HideAInOut[GivenA] {
+      type Out = GivenA
+      def get(left: GivenA): Out = left
+    }
+}