rust/tests/mir-opt/building/async_await.rs

// skip-filecheck
// This test makes sure that the coroutine MIR pass eliminates all calls to
// `get_context`, and that the MIR argument type for an async fn and all locals
// related to `yield` are `&mut Context`, and its return type is `Poll`.

//@ edition:2018
//@ compile-flags: -C panic=abort

#![crate_type = "lib"]

// EMIT_MIR async_await.a-{closure#0}.coroutine_resume.0.mir
async fn a() {}

// EMIT_MIR async_await.b-{closure#0}.coroutine_resume.0.mir
pub async fn b() {
    a().await;
    a().await
}
Allow to run filecheck in mir-opt tests. 2023-10-16 12:36:39 -05:00			`// skip-filecheck`
s/generator/coroutine/ 2023-10-19 16:46:28 -05:00			`// This test makes sure that the coroutine MIR pass eliminates all calls to`
Transform async ResumeTy in generator transform - Eliminates all the `get_context` calls that async lowering created. - Replace all `Local` `ResumeTy` types with `&mut Context<'_>`. The `Local`s that have their types replaced are: - The `resume` argument itself. - The argument to `get_context`. - The yielded value of a `yield`. The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the `get_context` function is being used to convert that back to a `&mut Context<'_>`. Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection, but rather directly use `&mut Context<'_>`, however that would currently lead to higher-kinded lifetime errors. See <https://github.com/rust-lang/rust/issues/105501>. The async lowering step and the type / lifetime inference / checking are still using the `ResumeTy` indirection for the time being, and that indirection is removed here. After this transform, the generator body only knows about `&mut Context<'_>`. 2022-12-20 08:15:29 -06:00			// `get_context`, and that the MIR argument type for an async fn and all locals
			// related to `yield` are `&mut Context`, and its return type is `Poll`.

			`//@ edition:2018`
			`//@ compile-flags: -C panic=abort`

			`#![crate_type = "lib"]`

s/generator/coroutine/ 2023-10-19 16:46:28 -05:00			`// EMIT_MIR async_await.a-{closure#0}.coroutine_resume.0.mir`
Transform async ResumeTy in generator transform - Eliminates all the `get_context` calls that async lowering created. - Replace all `Local` `ResumeTy` types with `&mut Context<'_>`. The `Local`s that have their types replaced are: - The `resume` argument itself. - The argument to `get_context`. - The yielded value of a `yield`. The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the `get_context` function is being used to convert that back to a `&mut Context<'_>`. Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection, but rather directly use `&mut Context<'_>`, however that would currently lead to higher-kinded lifetime errors. See <https://github.com/rust-lang/rust/issues/105501>. The async lowering step and the type / lifetime inference / checking are still using the `ResumeTy` indirection for the time being, and that indirection is removed here. After this transform, the generator body only knows about `&mut Context<'_>`. 2022-12-20 08:15:29 -06:00			`async fn a() {}`

s/generator/coroutine/ 2023-10-19 16:46:28 -05:00			`// EMIT_MIR async_await.b-{closure#0}.coroutine_resume.0.mir`
Transform async ResumeTy in generator transform - Eliminates all the `get_context` calls that async lowering created. - Replace all `Local` `ResumeTy` types with `&mut Context<'_>`. The `Local`s that have their types replaced are: - The `resume` argument itself. - The argument to `get_context`. - The yielded value of a `yield`. The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the `get_context` function is being used to convert that back to a `&mut Context<'_>`. Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection, but rather directly use `&mut Context<'_>`, however that would currently lead to higher-kinded lifetime errors. See <https://github.com/rust-lang/rust/issues/105501>. The async lowering step and the type / lifetime inference / checking are still using the `ResumeTy` indirection for the time being, and that indirection is removed here. After this transform, the generator body only knows about `&mut Context<'_>`. 2022-12-20 08:15:29 -06:00			`pub async fn b() {`
			`a().await;`
			`a().await`
			`}`