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Tweak E0277 when predicate comes indirectly from ? - #137245
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When a `?` operation requires an `Into` conversion with additional bounds (like having a concrete error but wanting to convert to a trait object), we handle it speficically and provide the same kind of information we give other `?` related errors.
```
error[E0277]: `?` couldn't convert the error: `E: std::error::Error` is not satisfied
--> $DIR/bad-question-mark-on-trait-object.rs:5:13
|
LL | fn foo() -> Result<(), Box<dyn std::error::Error>> {
| -------------------------------------- required `E: std::error::Error` because of this
LL | Ok(bar()?)
| ^ the trait `std::error::Error` is not implemented for `E`
|
= note: the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait
= note: required for `Box<dyn std::error::Error>` to implement `From<E>`
```
Avoid talking about `FromResidual` when other more relevant information is being given, particularly from `rust_on_unimplemented`.estebankforce-pushed
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just a nit, this is gonna be very useful!
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```
error[E0277]: `?` couldn't convert the error: `E: std::error::Error` is not satisfied
--> $DIR/bad-question-mark-on-trait-object.rs:7:13
|
LL | fn foo() -> Result<(), Box<dyn std::error::Error>> {
| -------------------------------------- required `E: std::error::Error` because of this
LL | Ok(bar()?)
| -----^ the trait `std::error::Error` is not implemented for `E`
| |
| this has type `Result<_, E>`
|
note: `E` needs to implement `std::error::Error`
--> $DIR/bad-question-mark-on-trait-object.rs:1:1
|
LL | struct E;
| ^^^^^^^^
= note: the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait
= note: required for `Box<dyn std::error::Error>` to implement `From<E>`
error[E0277]: `?` couldn't convert the error to `X`
--> $DIR/bad-question-mark-on-trait-object.rs:18:13
|
LL | fn bat() -> Result<(), X> {
| ------------- expected `X` because of this
LL | Ok(bar()?)
| -----^ the trait `From<E>` is not implemented for `X`
| |
| this can't be annotated with `?` because it has type `Result<_, E>`
|
note: `X` needs to implement `From<E>`
--> $DIR/bad-question-mark-on-trait-object.rs:4:1
|
LL | struct X;
| ^^^^^^^^
note: alternatively, `E` needs to implement `Into<X>`
--> $DIR/bad-question-mark-on-trait-object.rs:1:1
|
LL | struct E;
| ^^^^^^^^
= note: the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait
```estebankforce-pushed
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@bors r+ |
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…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#136458 (Do not deduplicate list of associated types provided by dyn principal) - rust-lang#136474 ([`compiletest`-related cleanups 3/7] Make the distinction between sources root vs test suite sources root in compiletest less confusing) - rust-lang#136592 (Make sure we don't overrun the stack in canonicalizer) - rust-lang#136787 (Remove `lifetime_capture_rules_2024` feature) - rust-lang#137207 (Add #[track_caller] to Duration Div impl) - rust-lang#137245 (Tweak E0277 when predicate comes indirectly from ?) - rust-lang#137257 (Ignore fake borrows for packed field check) - rust-lang#137399 (fix ICE in layout computation with unnormalizable const) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup merge of rust-lang#137245 - estebank:from-residual-note-2, r=oli-obk Tweak E0277 when predicate comes indirectly from ? When a `?` operation requires an `Into` conversion with additional bounds (like having a concrete error but wanting to convert to a trait object), we handle it speficically and provide the same kind of information we give other `?` related errors. ``` error[E0277]: `?` couldn't convert the error: `E: std::error::Error` is not satisfied --> $DIR/bad-question-mark-on-trait-object.rs:7:13 | LL | fn foo() -> Result<(), Box<dyn std::error::Error>> { | -------------------------------------- required `E: std::error::Error` because of this LL | Ok(bar()?) | -----^ the trait `std::error::Error` is not implemented for `E` | | | this has type `Result<_, E>` | note: `E` needs to implement `std::error::Error` --> $DIR/bad-question-mark-on-trait-object.rs:1:1 | LL | struct E; | ^^^^^^^^ = note: the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait = note: required for `Box<dyn std::error::Error>` to implement `From<E>` ``` Avoid talking about `FromResidual` when other more relevant information is being given, particularly from `rust_on_unimplemented`. Fixrust-lang#137238. ----- CC rust-lang#137232, which was a smaller step related to this.
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When a
?operation requires anIntoconversion with additional bounds (like having a concrete error but wanting to convert to a trait object), we handle it speficically and provide the same kind of information we give other?related errors.Avoid talking about
FromResidualwhen other more relevant information is being given, particularly fromrust_on_unimplemented.Fix#137238.
CC #137232, which was a smaller step related to this.