error[E0261]: use of undeclared lifetime name `'a` --> $DIR/issue-69136-inner-lifetime-resolve-error.rs:17:65 | LL | type Return = impl WithAssoc; | ^^ undeclared lifetime | = note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html help: consider making the bound lifetime-generic with a new `'a` lifetime | LL | type Return = impl for<'a> WithAssoc; | +++++++ help: consider introducing lifetime `'a` here | LL | type Return<'a, A> = impl WithAssoc; | +++ error: non-defining opaque type use in defining scope --> $DIR/issue-69136-inner-lifetime-resolve-error.rs:20:27 | LL | fn my_fun() -> Return<()> {} | ^^ | note: used non-generic type `()` for generic parameter --> $DIR/issue-69136-inner-lifetime-resolve-error.rs:17:13 | LL | type Return = impl WithAssoc; | ^ error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0261`.