error[E0277]: `std::rc::Rc<()>` cannot be sent between threads safely --> $DIR/async-fn-nonsend.rs:50:5 | LL | fn assert_send(_: impl Send) {} | ----------- ---- required by this bound in `assert_send` ... LL | assert_send(local_dropped_before_await()); | ^^^^^^^^^^^ `std::rc::Rc<()>` cannot be sent between threads safely | = help: within `impl std::future::Future`, the trait `std::marker::Send` is not implemented for `std::rc::Rc<()>` = note: required because it appears within the type `impl std::fmt::Debug` = note: required because it appears within the type `{impl std::fmt::Debug, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}` = note: required because it appears within the type `[static generator@$DIR/async-fn-nonsend.rs:21:39: 26:2 {impl std::fmt::Debug, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}]` = note: required because it appears within the type `std::future::GenFuture<[static generator@$DIR/async-fn-nonsend.rs:21:39: 26:2 {impl std::fmt::Debug, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}]>` = note: required because it appears within the type `impl std::future::Future` = note: required because it appears within the type `impl std::future::Future` error[E0277]: `std::rc::Rc<()>` cannot be sent between threads safely --> $DIR/async-fn-nonsend.rs:52:5 | LL | fn assert_send(_: impl Send) {} | ----------- ---- required by this bound in `assert_send` ... LL | assert_send(non_send_temporary_in_match()); | ^^^^^^^^^^^ `std::rc::Rc<()>` cannot be sent between threads safely | = help: within `impl std::future::Future`, the trait `std::marker::Send` is not implemented for `std::rc::Rc<()>` = note: required because it appears within the type `impl std::fmt::Debug` = note: required because it appears within the type `{fn(impl std::fmt::Debug) -> std::option::Option {std::option::Option::::Some}, fn() -> impl std::fmt::Debug {non_send}, impl std::fmt::Debug, std::option::Option, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}` = note: required because it appears within the type `[static generator@$DIR/async-fn-nonsend.rs:28:40: 37:2 {fn(impl std::fmt::Debug) -> std::option::Option {std::option::Option::::Some}, fn() -> impl std::fmt::Debug {non_send}, impl std::fmt::Debug, std::option::Option, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}]` = note: required because it appears within the type `std::future::GenFuture<[static generator@$DIR/async-fn-nonsend.rs:28:40: 37:2 {fn(impl std::fmt::Debug) -> std::option::Option {std::option::Option::::Some}, fn() -> impl std::fmt::Debug {non_send}, impl std::fmt::Debug, std::option::Option, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}]>` = note: required because it appears within the type `impl std::future::Future` = note: required because it appears within the type `impl std::future::Future` error[E0277]: `dyn std::fmt::Write` cannot be sent between threads safely --> $DIR/async-fn-nonsend.rs:54:5 | LL | fn assert_send(_: impl Send) {} | ----------- ---- required by this bound in `assert_send` ... LL | assert_send(non_sync_with_method_call()); | ^^^^^^^^^^^ `dyn std::fmt::Write` cannot be sent between threads safely | = help: the trait `std::marker::Send` is not implemented for `dyn std::fmt::Write` = note: required because of the requirements on the impl of `std::marker::Send` for `&mut dyn std::fmt::Write` = note: required because it appears within the type `std::fmt::Formatter<'_>` = note: required because of the requirements on the impl of `std::marker::Send` for `&mut std::fmt::Formatter<'_>` = note: required because it appears within the type `for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}` = note: required because it appears within the type `[static generator@$DIR/async-fn-nonsend.rs:39:38: 45:2 for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}]` = note: required because it appears within the type `std::future::GenFuture<[static generator@$DIR/async-fn-nonsend.rs:39:38: 45:2 for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}]>` = note: required because it appears within the type `impl std::future::Future` = note: required because it appears within the type `impl std::future::Future` error[E0277]: `*mut (dyn std::ops::Fn() + 'static)` cannot be shared between threads safely --> $DIR/async-fn-nonsend.rs:54:5 | LL | fn assert_send(_: impl Send) {} | ----------- ---- required by this bound in `assert_send` ... LL | assert_send(non_sync_with_method_call()); | ^^^^^^^^^^^ `*mut (dyn std::ops::Fn() + 'static)` cannot be shared between threads safely | = help: within `std::fmt::ArgumentV1<'_>`, the trait `std::marker::Sync` is not implemented for `*mut (dyn std::ops::Fn() + 'static)` = note: required because it appears within the type `std::marker::PhantomData<*mut (dyn std::ops::Fn() + 'static)>` = note: required because it appears within the type `core::fmt::Void` = note: required because it appears within the type `&core::fmt::Void` = note: required because it appears within the type `std::fmt::ArgumentV1<'_>` = note: required because of the requirements on the impl of `std::marker::Send` for `std::slice::Iter<'_, std::fmt::ArgumentV1<'_>>` = note: required because it appears within the type `std::fmt::Formatter<'_>` = note: required because of the requirements on the impl of `std::marker::Send` for `&mut std::fmt::Formatter<'_>` = note: required because it appears within the type `for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}` = note: required because it appears within the type `[static generator@$DIR/async-fn-nonsend.rs:39:38: 45:2 for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}]` = note: required because it appears within the type `std::future::GenFuture<[static generator@$DIR/async-fn-nonsend.rs:39:38: 45:2 for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}]>` = note: required because it appears within the type `impl std::future::Future` = note: required because it appears within the type `impl std::future::Future` error: aborting due to 4 previous errors For more information about this error, try `rustc --explain E0277`.