This improves help messages in two cases:
- When expected type is `T` and found type is `&T`, we now look through blocks
and suggest dereferencing the expression of the block, rather than the whole
block.
- In the above case, if the expression is an `&`, we not suggest removing the
`&` instead of adding `*`.
Both of these are demonstrated in the regression test. Before this patch the
first error in the test would be:
error[E0308]: `if` and `else` have incompatible types
--> test.rs:8:9
|
5 | / if true {
6 | | a
| | - expected because of this
7 | | } else {
8 | | b
| | ^ expected `usize`, found `&usize`
9 | | };
| |_____- `if` and `else` have incompatible types
|
help: consider dereferencing the borrow
|
7 | } else *{
8 | b
9 | };
|
Now:
error[E0308]: `if` and `else` have incompatible types
--> test.rs:8:9
|
5 | / if true {
6 | | a
| | - expected because of this
7 | | } else {
8 | | b
| | ^
| | |
| | expected `usize`, found `&usize`
| | help: consider dereferencing the borrow: `*b`
9 | | };
| |_____- `if` and `else` have incompatible types
The second error:
error[E0308]: `if` and `else` have incompatible types
--> test.rs:14:9
|
11 | / if true {
12 | | 1
| | - expected because of this
13 | | } else {
14 | | &1
| | ^^ expected integer, found `&{integer}`
15 | | };
| |_____- `if` and `else` have incompatible types
|
help: consider dereferencing the borrow
|
13 | } else *{
14 | &1
15 | };
|
now:
error[E0308]: `if` and `else` have incompatible types
--> test.rs:14:9
|
11 | / if true {
12 | | 1
| | - expected because of this
13 | | } else {
14 | | &1
| | ^-
| | ||
| | |help: consider removing the `&`: `1`
| | expected integer, found `&{integer}`
15 | | };
| |_____- `if` and `else` have incompatible types
Fixes#82361
Suggest `return`ing tail expressions that match return type
Some newcomers are confused by the behavior of tail expressions,
interpreting that "leaving out the `;` makes it the return value".
To help them go in the right direction, suggest using `return` instead
when applicable.
When a tail expression isn't unit, we previously always suggested adding
a trailing `;` to turn it into a statement. This suggestion isn't
appropriate for any expression that doesn't have side-effects, as the
user will have likely wanted to call something else or do something with
the resulting value, instead of just discarding it.
ast: Keep expansion status for out-of-line module items
I.e. whether a module `mod foo;` is already loaded from a file or not.
This is a pre-requisite to correctly treating inner attributes on such modules (https://github.com/rust-lang/rust/issues/81661).
With this change AST structures for `mod` items diverge even more for AST structure for the crate root, which previously used `ast::Mod`.
Therefore this PR removes `ast::Mod` from `ast::Crate` in the first commit, these two things are sufficiently different from each other, at least at syntactic level.
Customization points for visiting a "`mod` item or crate root" were also removed from AST visitors (`fn visit_mod`).
`ast::Mod` itself was refactored away in the second commit in favor of `ItemKind::Mod(Unsafe, ModKind)`.
name async generators something more human friendly in type error diagnostic
fixes#81457
Some details:
1. I opted to load the generator kind from the hir in TyCategory. I also use 1 impl in the hir for the descr
2. I named both the source of the future, in addition to the general type (`future`), not sure what is preferred
3. I am not sure what is required to make sure "generator" is not referred to anywhere. A brief `rg "\"generator\"" showed me that most diagnostics correctly distinguish from generators and async generator, but the `descr` of `DefKind` is pretty general (not sure how thats used)
4. should the descr impl of AsyncGeneratorKind use its display impl instead of copying the string?
Crate root is sufficiently different from `mod` items, at least at syntactic level.
Also remove customization point for "`mod` item or crate root" from AST visitors.
This renames the variants in HIR UnOp from
enum UnOp {
UnDeref,
UnNot,
UnNeg,
}
to
enum UnOp {
Deref,
Not,
Neg,
}
Motivations:
- This is more consistent with the rest of the code base where most enum
variants don't have a prefix.
- These variants are never used without the `UnOp` prefix so the extra
`Un` prefix doesn't help with readability. E.g. we don't have any
`UnDeref`s in the code, we only have `UnOp::UnDeref`.
- MIR `UnOp` type variants don't have a prefix so this is more
consistent with MIR types.
- "un" prefix reads like "inverse" or "reverse", so as a beginner in
rustc code base when I see "UnDeref" what comes to my mind is
something like "&*" instead of just "*".
Refactor `PrimitiveTypeTable` for Clippy
I removed `PrimitiveTypeTable` and added `PrimTy::ALL` and `PrimTy::from_name` in its place. This allows Clippy to use `PrimTy::from_name` for the `builtin_type_shadow` lint, and a `const` list of primitive types is deleted from Clippy code (the goal). All changes should be a little faster, if anything.
Rework diagnostics for wrong number of generic args (fixes#66228 and #71924)
This PR reworks the `wrong number of {} arguments` message, so that it provides more details and contextual hints.
This makes it possible to pass the `Impl` directly to functions, instead
of having to pass each of the many fields one at a time. It also
simplifies matches in many cases.
Add check for `[T;N]`/`usize` mismatch in astconv
Helps clarify the issue in #80506
by adding a specific check for mismatches between [T;N] and usize.
r? `@lcnr`
- Adds optional default values to const generic parameters in the AST
and HIR
- Parses these optional default values
- Adds a `const_generics_defaults` feature gate
Implement if-let match guards
Implements rust-lang/rfcs#2294 (tracking issue: #51114).
I probably should do a few more things before this can be merged:
- [x] Add tests (added basic tests, more advanced tests could be done in the future?)
- [x] Add lint for exhaustive if-let guard (comparable to normal if-let statements)
- [x] Fix clippy
However since this is a nightly feature maybe it's fine to land this and do those steps in follow-up PRs.
Thanks a lot `@matthewjasper` ❤️ for helping me with lowering to MIR! Would you be interested in reviewing this?
r? `@ghost` for now
