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

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Add suggestion for missing `.await` keyword
2019-06-19 20:55:18 +00:00
error[E0308]: mismatched types
--bless post no async_await gates in tests.
2019-08-02 01:48:43 +00:00
--> $DIR/dont-suggest-missing-await.rs:14:18
Add suggestion for missing `.await` keyword
2019-06-19 20:55:18 +00:00
|
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 18:03:54 +00:00
| -------- ^ 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.
2022-01-22 04:50:54 +00:00
| |
| arguments to this function are incorrect
Add suggestion for missing `.await` keyword
2019-06-19 20:55:18 +00:00
|
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 18:03:54 +00:00
note: calling an async function returns a future
--> $DIR/dont-suggest-missing-await.rs:14:18
|
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.
2022-01-22 04:50:54 +00:00
note: function defined here
--> $DIR/dont-suggest-missing-await.rs:5:4
|
LL | fn take_u32(x: u32) {}
| ^^^^^^^^ ------
Add more `.await` suggestions on E0308
2020-10-23 02:03:36 +00:00
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
2021-06-22 02:07:19 +00:00
| ++++++
Add suggestion for missing `.await` keyword
2019-06-19 20:55:18 +00:00
Show number in error message even for one error Co-authored-by: Adrian <adrian.iosdev@gmail.com>
2023-11-21 15:44:16 +00:00
error: aborting due to 1 previous error
Add suggestion for missing `.await` keyword
2019-06-19 20:55:18 +00:00
For more information about this error, try `rustc --explain E0308`.
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