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rust/tests/ui/async-await/suggest-missing-await.stderr

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Add suggestion for missing `.await` keyword
2019-06-19 15:55:18 -05:00
error[E0308]: mismatched types
Add more `.await` suggestions on E0308
2020-10-22 21:03:36 -05:00
--> $DIR/suggest-missing-await.rs:12:14
Add suggestion for missing `.await` keyword
2019-06-19 15:55:18 -05:00
|
LL | take_u32(x)
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 `u32`, found future
Implementation for 65853 This attempts to bring better error messages to invalid method calls, by applying some heuristics to identify common mistakes. The algorithm is inspired by Levenshtein distance and longest common sub-sequence. In essence, we treat the types of the function, and the types of the arguments you provided as two "words" and compute the edits to get from one to the other. We then modify that algorithm to detect 4 cases: - A function input is missing - An extra argument was provided - The type of an argument is straight up invalid - Two arguments have been swapped - A subset of the arguments have been shuffled (We detect the last two as separate cases so that we can detect two swaps, instead of 4 parameters permuted.) It helps to understand this argument by paying special attention to terminology: "inputs" refers to the inputs being *expected* by the function, and "arguments" refers to what has been provided at the call site. The basic sketch of the algorithm is as follows: - Construct a boolean grid, with a row for each argument, and a column for each input. The cell [i, j] is true if the i'th argument could satisfy the j'th input. - If we find an argument that could satisfy no inputs, provided for an input that can't be satisfied by any other argument, we consider this an "invalid type". - Extra arguments are those that can't satisfy any input, provided for an input that *could* be satisfied by another argument. - Missing inputs are inputs that can't be satisfied by any argument, where the provided argument could satisfy another input - Swapped / Permuted arguments are identified with a cycle detection algorithm. As each issue is found, we remove the relevant inputs / arguments and check for more issues. If we find no issues, we match up any "valid" arguments, and start again. Note that there's a lot of extra complexity: - We try to stay efficient on the happy path, only computing the diagonal until we find a problem, and then filling in the rest of the matrix. - Closure arguments are wrapped in a tuple and need to be unwrapped - We need to resolve closure types after the rest, to allow the most specific type constraints - We need to handle imported C functions that might be variadic in their inputs. I tried to document a lot of this in comments in the code and keep the naming clear.
2022-01-21 22:50:54 -06:00
| |
| arguments to this function are incorrect
Add suggestion for missing `.await` keyword
2019-06-19 15:55:18 -05:00
|
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
note: calling an async function returns a future
--> $DIR/suggest-missing-await.rs:12:14
|
LL | take_u32(x)
| ^
Implementation for 65853 This attempts to bring better error messages to invalid method calls, by applying some heuristics to identify common mistakes. The algorithm is inspired by Levenshtein distance and longest common sub-sequence. In essence, we treat the types of the function, and the types of the arguments you provided as two "words" and compute the edits to get from one to the other. We then modify that algorithm to detect 4 cases: - A function input is missing - An extra argument was provided - The type of an argument is straight up invalid - Two arguments have been swapped - A subset of the arguments have been shuffled (We detect the last two as separate cases so that we can detect two swaps, instead of 4 parameters permuted.) It helps to understand this argument by paying special attention to terminology: "inputs" refers to the inputs being *expected* by the function, and "arguments" refers to what has been provided at the call site. The basic sketch of the algorithm is as follows: - Construct a boolean grid, with a row for each argument, and a column for each input. The cell [i, j] is true if the i'th argument could satisfy the j'th input. - If we find an argument that could satisfy no inputs, provided for an input that can't be satisfied by any other argument, we consider this an "invalid type". - Extra arguments are those that can't satisfy any input, provided for an input that *could* be satisfied by another argument. - Missing inputs are inputs that can't be satisfied by any argument, where the provided argument could satisfy another input - Swapped / Permuted arguments are identified with a cycle detection algorithm. As each issue is found, we remove the relevant inputs / arguments and check for more issues. If we find no issues, we match up any "valid" arguments, and start again. Note that there's a lot of extra complexity: - We try to stay efficient on the happy path, only computing the diagonal until we find a problem, and then filling in the rest of the matrix. - Closure arguments are wrapped in a tuple and need to be unwrapped - We need to resolve closure types after the rest, to allow the most specific type constraints - We need to handle imported C functions that might be variadic in their inputs. I tried to document a lot of this in comments in the code and keep the naming clear.
2022-01-21 22:50:54 -06:00
note: function defined here
--> $DIR/suggest-missing-await.rs:3:4
|
LL | fn take_u32(_x: u32) {}
| ^^^^^^^^ -------
Tweak "use `.await`" suggestion
2020-10-21 16:25:09 -05:00
help: consider `await`ing on the `Future`
|
LL | take_u32(x.await)
Modify structured suggestion output * On suggestions that include deletions, use a diff inspired output format * When suggesting addition, use `+` as underline * Color highlight modified span
2021-06-21 21:07:19 -05:00
| ++++++
Add suggestion for missing `.await` keyword
2019-06-19 15:55:18 -05:00
Emit coercion suggestions in more places Fixes #66910 We have several different kinds of suggestions we can try to make when type coercion fails. However, we were previously only emitting these suggestions from `demand_coerce_diag`. This resulted in the compiler failing to emit applicable suggestions in several different cases, such as when the implicit return value of a function had the wrong type. This commit adds a new `emit_coerce_suggestions` method, which tries to emit a number of related suggestions. This method is called from both `demand_coerce_diag` and `CoerceMany::coerce_inner`, which covers a much wider range of cases than before. We now suggest using `.await` in more cases where it is applicable, among other improvements.
2019-12-03 19:32:50 -06:00
error[E0308]: mismatched types
Add more `.await` suggestions on E0308
2020-10-22 21:03:36 -05:00
--> $DIR/suggest-missing-await.rs:22:5
Emit coercion suggestions in more places Fixes #66910 We have several different kinds of suggestions we can try to make when type coercion fails. However, we were previously only emitting these suggestions from `demand_coerce_diag`. This resulted in the compiler failing to emit applicable suggestions in several different cases, such as when the implicit return value of a function had the wrong type. This commit adds a new `emit_coerce_suggestions` method, which tries to emit a number of related suggestions. This method is called from both `demand_coerce_diag` and `CoerceMany::coerce_inner`, which covers a much wider range of cases than before. We now suggest using `.await` in more cases where it is applicable, among other improvements.
2019-12-03 19:32:50 -06:00
|
LL | dummy()
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 `()`, found future
Emit coercion suggestions in more places Fixes #66910 We have several different kinds of suggestions we can try to make when type coercion fails. However, we were previously only emitting these suggestions from `demand_coerce_diag`. This resulted in the compiler failing to emit applicable suggestions in several different cases, such as when the implicit return value of a function had the wrong type. This commit adds a new `emit_coerce_suggestions` method, which tries to emit a number of related suggestions. This method is called from both `demand_coerce_diag` and `CoerceMany::coerce_inner`, which covers a much wider range of cases than before. We now suggest using `.await` in more cases where it is applicable, among other improvements.
2019-12-03 19:32:50 -06:00
|
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
note: calling an async function returns a future
--> $DIR/suggest-missing-await.rs:22:5
|
LL | dummy()
| ^^^^^^^
Tweak "use `.await`" suggestion
2020-10-21 16:25:09 -05:00
help: consider `await`ing on the `Future`
Emit coercion suggestions in more places Fixes #66910 We have several different kinds of suggestions we can try to make when type coercion fails. However, we were previously only emitting these suggestions from `demand_coerce_diag`. This resulted in the compiler failing to emit applicable suggestions in several different cases, such as when the implicit return value of a function had the wrong type. This commit adds a new `emit_coerce_suggestions` method, which tries to emit a number of related suggestions. This method is called from both `demand_coerce_diag` and `CoerceMany::coerce_inner`, which covers a much wider range of cases than before. We now suggest using `.await` in more cases where it is applicable, among other improvements.
2019-12-03 19:32:50 -06:00
|
LL | dummy().await
Modify structured suggestion output * On suggestions that include deletions, use a diff inspired output format * When suggesting addition, use `+` as underline * Color highlight modified span
2021-06-21 21:07:19 -05:00
| ++++++
Revert "Auto merge of #92007 - oli-obk:lazy_tait2, r=nikomatsakis" This reverts commit e7cc3bddbe0d0e374d05e7003e662bba1742dbae, reversing changes made to 734368a200904ef9c21db86c595dc04263c87be0.
2022-02-11 01:18:06 -06:00
help: consider using a semicolon here
|
LL | dummy();
| +
Emit coercion suggestions in more places Fixes #66910 We have several different kinds of suggestions we can try to make when type coercion fails. However, we were previously only emitting these suggestions from `demand_coerce_diag`. This resulted in the compiler failing to emit applicable suggestions in several different cases, such as when the implicit return value of a function had the wrong type. This commit adds a new `emit_coerce_suggestions` method, which tries to emit a number of related suggestions. This method is called from both `demand_coerce_diag` and `CoerceMany::coerce_inner`, which covers a much wider range of cases than before. We now suggest using `.await` in more cases where it is applicable, among other improvements.
2019-12-03 19:32:50 -06:00
Fix await suggestion better
2021-11-16 00:51:20 -06:00
error[E0308]: `if` and `else` have incompatible types
Revert "Auto merge of #92007 - oli-obk:lazy_tait2, r=nikomatsakis" This reverts commit e7cc3bddbe0d0e374d05e7003e662bba1742dbae, reversing changes made to 734368a200904ef9c21db86c595dc04263c87be0.
2022-02-11 01:18:06 -06:00
--> $DIR/suggest-missing-await.rs:35:9
Fix await suggestion better
2021-11-16 00:51:20 -06:00
|
LL | let _x = if true {
| ______________-
LL | | dummy()
| | ------- expected because of this
LL | |
LL | | } else {
LL | | dummy().await
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 future, found `()`
Fix await suggestion better
2021-11-16 00:51:20 -06:00
LL | |
LL | | };
| |_____- `if` and `else` have incompatible types
|
Resolve vars in note_type_err
2022-04-17 14:00:32 -05:00
= note: expected opaque type `impl Future<Output = ()>`
found unit type `()`
Fix await suggestion better
2021-11-16 00:51:20 -06:00
help: consider `await`ing on the `Future`
|
LL | dummy().await
| ++++++
error[E0308]: `match` arms have incompatible types
Revert "Auto merge of #92007 - oli-obk:lazy_tait2, r=nikomatsakis" This reverts commit e7cc3bddbe0d0e374d05e7003e662bba1742dbae, reversing changes made to 734368a200904ef9c21db86c595dc04263c87be0.
2022-02-11 01:18:06 -06:00
--> $DIR/suggest-missing-await.rs:45:14
Fix await suggestion better
2021-11-16 00:51:20 -06:00
|
LL | let _x = match 0usize {
| ______________-
LL | | 0 => dummy(),
Print output ty for opaque future ty
2021-11-16 18:16:23 -06:00
| | ------- this is found to be of type `impl Future<Output = ()>`
Fix await suggestion better
2021-11-16 00:51:20 -06:00
LL | | 1 => dummy(),
Print output ty for opaque future ty
2021-11-16 18:16:23 -06:00
| | ------- this is found to be of type `impl Future<Output = ()>`
Fix await suggestion better
2021-11-16 00:51:20 -06:00
LL | | 2 => dummy().await,
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 future, found `()`
Fix await suggestion better
2021-11-16 00:51:20 -06:00
LL | |
LL | | };
| |_____- `match` arms have incompatible types
|
Print output ty for opaque future ty
2021-11-16 18:16:23 -06:00
= note: expected opaque type `impl Future<Output = ()>`
Fix await suggestion better
2021-11-16 00:51:20 -06:00
found unit type `()`
help: consider `await`ing on the `Future`
|
LL ~ 0 => dummy().await,
LL ~ 1 => dummy().await,
|
error[E0308]: mismatched types
Revert "Auto merge of #92007 - oli-obk:lazy_tait2, r=nikomatsakis" This reverts commit e7cc3bddbe0d0e374d05e7003e662bba1742dbae, reversing changes made to 734368a200904ef9c21db86c595dc04263c87be0.
2022-02-11 01:18:06 -06:00
--> $DIR/suggest-missing-await.rs:53:9
Fix await suggestion better
2021-11-16 00:51:20 -06:00
|
Point (again) to more expressions with their type, even if not fully resolved
2021-12-15 17:16:21 -06:00
LL | let _x = match dummy() {
| ------- this expression has type `impl Future<Output = ()>`
Fix await suggestion better
2021-11-16 00:51:20 -06:00
LL | () => {}
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 future, found `()`
Fix await suggestion better
2021-11-16 00:51:20 -06:00
|
Print output ty for opaque future ty
2021-11-16 18:16:23 -06:00
= note: expected opaque type `impl Future<Output = ()>`
Fix await suggestion better
2021-11-16 00:51:20 -06:00
found unit type `()`
help: consider `await`ing on the `Future`
|
LL | let _x = match dummy().await {
| ++++++
Suggest await on cases involving infer
2021-11-17 23:38:04 -06:00
error[E0308]: mismatched types
Revert "Auto merge of #92007 - oli-obk:lazy_tait2, r=nikomatsakis" This reverts commit e7cc3bddbe0d0e374d05e7003e662bba1742dbae, reversing changes made to 734368a200904ef9c21db86c595dc04263c87be0.
2022-02-11 01:18:06 -06:00
--> $DIR/suggest-missing-await.rs:67:9
Suggest await on cases involving infer
2021-11-17 23:38:04 -06:00
|
Point (again) to more expressions with their type, even if not fully resolved
2021-12-15 17:16:21 -06:00
LL | match dummy_result() {
| -------------- this expression has type `impl Future<Output = Result<(), ()>>`
...
Suggest await on cases involving infer
2021-11-17 23:38:04 -06:00
LL | Ok(_) => {}
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 future, found `Result<_, _>`
Suggest await on cases involving infer
2021-11-17 23:38:04 -06:00
|
Re-bless test outputs
2021-11-20 12:00:14 -06:00
= note: expected opaque type `impl Future<Output = Result<(), ()>>`
Suggest await on cases involving infer
2021-11-17 23:38:04 -06:00
found enum `Result<_, _>`
help: consider `await`ing on the `Future`
|
LL | match dummy_result().await {
| ++++++
error[E0308]: mismatched types
Revert "Auto merge of #92007 - oli-obk:lazy_tait2, r=nikomatsakis" This reverts commit e7cc3bddbe0d0e374d05e7003e662bba1742dbae, reversing changes made to 734368a200904ef9c21db86c595dc04263c87be0.
2022-02-11 01:18:06 -06:00
--> $DIR/suggest-missing-await.rs:69:9
Suggest await on cases involving infer
2021-11-17 23:38:04 -06:00
|
Point (again) to more expressions with their type, even if not fully resolved
2021-12-15 17:16:21 -06:00
LL | match dummy_result() {
| -------------- this expression has type `impl Future<Output = Result<(), ()>>`
...
Suggest await on cases involving infer
2021-11-17 23:38:04 -06:00
LL | Err(_) => {}
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 future, found `Result<_, _>`
Suggest await on cases involving infer
2021-11-17 23:38:04 -06:00
|
Re-bless test outputs
2021-11-20 12:00:14 -06:00
= note: expected opaque type `impl Future<Output = Result<(), ()>>`
Suggest await on cases involving infer
2021-11-17 23:38:04 -06:00
found enum `Result<_, _>`
help: consider `await`ing on the `Future`
|
LL | match dummy_result().await {
| ++++++
error: aborting due to 7 previous errors
Add suggestion for missing `.await` keyword
2019-06-19 15:55:18 -05:00
For more information about this error, try `rustc --explain E0308`.
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