error[E0599]: no method named `test` found for reference `&impl T1` in the current scope --> $DIR/issue-99597.rs:11:7 | LL | s.test(); | ^^^^ method not found in `&impl T1` | = help: items from traits can only be used if the type parameter is bounded by the trait help: the following trait defines an item `test`, perhaps you need to restrict type parameter `impl T1` with it: | LL | fn go(s: &(impl T1 + T2)) { | + +++++ error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0599`.