rust/tests/ui/impl-trait/issue-99914.stderr

error[E0308]: mismatched types
  --> $DIR/issue-99914.rs:9:27
   |
LL |     t.and_then(|t| -> _ { bar(t) });
   |                           ^^^^^^ expected `Result<_, Error>`, found future
   |
help: try wrapping the expression in `Ok`
   |
LL |     t.and_then(|t| -> _ { Ok(bar(t)) });
   |                           +++      +

error: aborting due to previous error

For more information about this error, try `rustc --explain E0308`.
Do not leak type variables from opaque type relation 2022-07-29 19:41:39 -05:00			`error[E0308]: mismatched types`
			`--> $DIR/issue-99914.rs:9:27`
			`\|`
			`LL \| t.and_then(\|t\| -> _ { bar(t) });`
fix: improve the suggestion on future not awaited Considering the following code ```rust fn foo() -> u8 { async fn async_fn() -> u8 { 22 } async_fn() } fn main() {} ``` the error generated before this commit from the compiler is ``` ➜ rust git:(macros/async_fn_suggestion) ✗ rustc test.rs --edition 2021 error[E0308]: mismatched types --> test.rs:4:5 \| 1 \| fn foo() -> u8 { \| -- expected `u8` because of return type ... 4 \| async_fn() \| ^^^^^^^^^^ expected `u8`, found opaque type \| = note: expected type `u8` found opaque type `impl Future<Output = u8>` help: consider `await`ing on the `Future` \| 4 \| async_fn().await \| ++++++ error: aborting due to previous error ``` In this case the error is nor perfect, and can confuse the user that do not know that the opaque type is the future. So this commit will propose (and conclude the work start in https://github.com/rust-lang/rust/issues/80658) to change the string `opaque type` to `future` when applicable and also remove the Expected vs Received note by adding a more specific one regarding the async function that return a future type. So the new error emitted by the compiler is ``` error[E0308]: mismatched types --> test.rs:4:5 \| 1 \| fn foo() -> u8 { \| -- expected `u8` because of return type ... 4 \| async_fn() \| ^^^^^^^^^^ expected `u8`, found future \| note: calling an async function returns a future --> test.rs:4:5 \| 4 \| async_fn() \| ^^^^^^^^^^ help: consider `await`ing on the `Future` \| 4 \| async_fn().await \| ++++++ error: aborting due to previous error ``` Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> 2023-02-10 12:03:54 -06:00			\| ^^^^^^ expected `Result<_, Error>`, found future
Do not leak type variables from opaque type relation 2022-07-29 19:41:39 -05:00			`\|`
			help: try wrapping the expression in `Ok`
			`\|`
			`LL \| t.and_then(\|t\| -> _ { Ok(bar(t)) });`
			`\| +++ +`

			`error: aborting due to previous error`

			For more information about this error, try `rustc --explain E0308`.