use axum::{ async_trait, extract::{FromRequest, RequestParts}, }; use axum_macros::debug_handler; struct A; #[async_trait] impl FromRequest for A where B: Send, S: Send, { type Rejection = (); async fn from_request(_req: &mut RequestParts) -> Result { unimplemented!() } } impl A { #[debug_handler] async fn handler(&self) {} } fn main() {}