error[E0391]: cycle detected when processing `cycle1::{{impl-Trait}}` --> $DIR/auto-trait-leak.rs:24:16 | LL | fn cycle1() -> impl Clone { | ^^^^^^^^^^ | note: ...which requires processing `cycle1`... --> $DIR/auto-trait-leak.rs:24:1 | LL | fn cycle1() -> impl Clone { | ^^^^^^^^^^^^^^^^^^^^^^^^^ note: ...which requires evaluating trait selection obligation `impl std::clone::Clone: std::marker::Send`... note: ...which requires processing `cycle2::{{impl-Trait}}`... --> $DIR/auto-trait-leak.rs:33:16 | LL | fn cycle2() -> impl Clone { | ^^^^^^^^^^ note: ...which requires processing `cycle2`... --> $DIR/auto-trait-leak.rs:33:1 | LL | fn cycle2() -> impl Clone { | ^^^^^^^^^^^^^^^^^^^^^^^^^ note: ...which requires evaluating trait selection obligation `impl std::clone::Clone: std::marker::Send`... = note: ...which again requires processing `cycle1::{{impl-Trait}}`, completing the cycle error[E0391]: cycle detected when processing `cycle1::{{impl-Trait}}` --> $DIR/auto-trait-leak.rs:24:16 | LL | fn cycle1() -> impl Clone { | ^^^^^^^^^^ | note: ...which requires processing `cycle1`... --> $DIR/auto-trait-leak.rs:24:1 | LL | fn cycle1() -> impl Clone { | ^^^^^^^^^^^^^^^^^^^^^^^^^ note: ...which requires evaluating trait selection obligation `impl std::clone::Clone: std::marker::Send`... note: ...which requires processing `cycle2::{{impl-Trait}}`... --> $DIR/auto-trait-leak.rs:33:16 | LL | fn cycle2() -> impl Clone { | ^^^^^^^^^^ note: ...which requires processing `cycle2`... --> $DIR/auto-trait-leak.rs:33:1 | LL | fn cycle2() -> impl Clone { | ^^^^^^^^^^^^^^^^^^^^^^^^^ = note: ...which again requires processing `cycle1::{{impl-Trait}}`, completing the cycle error[E0277]: `std::rc::Rc` cannot be sent between threads safely --> $DIR/auto-trait-leak.rs:27:5 | LL | send(cycle2().clone()); | ^^^^ `std::rc::Rc` cannot be sent between threads safely | = help: within `impl std::clone::Clone`, the trait `std::marker::Send` is not implemented for `std::rc::Rc` = note: required because it appears within the type `impl std::clone::Clone` note: required by `send` --> $DIR/auto-trait-leak.rs:16:1 | LL | fn send(_: T) {} | ^^^^^^^^^^^^^^^^^^^^^^ error: aborting due to 3 previous errors Some errors occurred: E0277, E0391. For more information about an error, try `rustc --explain E0277`.