## Compiler version 3.7.0-RC1-bin-20250306-73ba485-NIGHTLY ## Minimized code ```scala def test[I, A](in: I)( run: I => Either[Throwable, A], onErr: Throwable => Throwable = identity[Throwable] ): Either[Throwable, A] = run(in) match { case Left(t) => Left(onErr(t)) case r @ Right(_) => r } ``` ## Output ```scala -- [E198] Unused Symbol Warning: /Users/matt/scala3.7-nightly-unused/src/main/scala/example/Test.scala:1:15 ------------ 1 |def test[I, A](in: I)( | ^^ | unused explicit parameter ``` ## Expectation `in` should not be reported unused since it's passed to `run`. If I remove the default param for `onErr` then it compiles without warning