| Age | Commit message (Collapse) | Author | Lines |
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When a type parameter shadows a primitive type, the error message
was non obvious. For example, given the file `file.rs`:
```rust
trait Parser<T> {
fn parse(text: &str) -> Option<T>;
}
impl<bool> Parser<bool> for bool {
fn parse(text: &str) -> Option<bool> {
Some(true)
}
}
fn main() {
println!("{}", bool::parse("ok").unwrap_or(false));
}
```
The output was:
```bash
% rustc file.rs
error[E0308]: mismatched types
--> file.rs:7:14
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7 | Some(true)
| ^^^^ expected type parameter, found bool
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= note: expected type `bool`
= note: found type `bool`
error: aborting due to previous error
```
We now show extra information about the type:
```bash
% rustc file.rs
error[E0308]: mismatched types
--> file.rs:7:14
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7 | Some(true)
| ^^^^ expected type parameter, found bool
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= note: expected type `bool` (type parameter)
= note: found type `bool` (bool)
error: aborting due to previous error
```
Fixes #35030
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Implement the `!` type
This implements the never type (`!`) and hides it behind the feature gate `#[feature(never_type)]`. With the feature gate off, things should build as normal (although some error messages may be different). With the gate on, `!` is usable as a type and diverging type variables (ie. types that are unconstrained by anything in the code) will default to `!` instead of `()`.
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Improve &-ptr printing
This PR replaces printing `&-ptr` with a more readable description. To do so it uses a few heuristics.
If the name of the type is unknown, too long (longer than just saying "reference"), or too complex (a type with explicit lifetime annotations), it will instead opt to print either "reference" or "mutable reference", depending on the mutability of the type.
Before:
```
error[E0308]: mismatched types
--> src/test/compile-fail/issue-7061.rs:14:46
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14 | fn foo(&'a mut self) -> Box<BarStruct> { self }
| ^^^^ expected box, found &-ptr
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= note: expected type `Box<BarStruct>`
= note: found type `&'a mut BarStruct`
error: aborting due to previous error
```
After:
```
error[E0308]: mismatched types
--> src/test/compile-fail/issue-7061.rs:14:46
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14 | fn foo(&'a mut self) -> Box<BarStruct> { self }
| ^^^^ expected box, found mutable reference
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= note: expected type `Box<BarStruct>`
= note: found type `&'a mut BarStruct`
error: aborting due to previous error
```
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Split Ty::is_empty method into is_never and is_uninhabited
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Add `TyKind::Empty` and fix resulting build errors.
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