Validate built-in attribute placement
Closes#54584, closes#47725, closes#54044.
I've changed silently ignoring some incorrectly placed attributes to errors. I'm not sure what the policy is since this can theoretically break code (should they be warnings instead? does it warrant a crater run?).
When encountering a `match` or `if` as a tail expression where the
different arms do not have the same type *and* the return type of that
`fn` is an `impl Trait`, check whether those arms can implement `Trait`
and if so, suggest using boxed trait objects.
Add help note when using type in place of const
This adds a small help note when it might be possible that wrapping a parameter in braces might resolve the issue of having a type where a const was expected.
Currently, I am displaying the `HirId`, and I'm not particularly sure where to get the currently displayed path(?).
r? `@lcnr`
Fixes#73268
When a deref coercion occurs, we may end up with a move error if the
base value has been partially moved out of. However, we do not indicate
anywhere that a deref coercion is occuring, resulting in an error
message with a confusing span.
This PR adds an explicit note to move errors when a deref coercion is
involved. We mention the name of the type that the deref-coercion
resolved to, as well as the `Deref::Target` associated type being used.
add the `const_evaluatable_checked` feature
Implements a rather small subset of https://github.com/rust-lang/compiler-team/issues/340
Unlike the MCP, this does not try to compare different constant, but instead only adds the constants found in where clauses
to the predicates of a function. This PR adds the feature gate `const_evaluatable_checked`, without which nothing should change.
r? @oli-obk @eddyb
This commit adjusts the missing field diagnostic logic for struct
patterns in typeck to improve the diagnostic when the missing fields are
inaccessible.
Signed-off-by: David Wood <david@davidtw.co>
This commit adjusts the missing field diagnostic logic for struct
expressions in typeck to improve the diagnostic when the missing
fields are inaccessible.
Signed-off-by: David Wood <david@davidtw.co>
Add help note to unconstrained const parameter
Resolves#68366, since it is currently intended behaviour.
If demonstrating `T -> U` is injective, there should be an additional word that it is not **yet** supported.
r? @lcnr
Add derive macro for specifying diagnostics using attributes.
Introduces `#[derive(SessionDiagnostic)]`, a derive macro for specifying structs that can be converted to Diagnostics using directions given by attributes on the struct and its fields. Currently, the following attributes have been implemented:
- `#[code = "..."]` -- this sets the Diagnostic's error code, and must be provided on the struct iself (ie, not on a field). Equivalent to calling `code`.
- `#[message = "..."]` -- this sets the Diagnostic's primary error message.
- `#[label = "..."]` -- this must be applied to fields of type `Span`, and is equivalent to `span_label`
- `#[suggestion(..)]` -- this allows a suggestion message to be supplied. This attribute must be applied to a field of type `Span` or `(Span, Applicability)`, and is equivalent to calling `span_suggestion`. Valid arguments are:
- `message = "..."` -- this sets the suggestion message.
- (Optional) `code = "..."` -- this suggests code for the suggestion. Defaults to empty.
`suggestion`also comes with other variants: `#[suggestion_short(..)]`, `#[suggestion_hidden(..)]` and `#[suggestion_verbose(..)]` which all take the same keys.
Within the strings passed to each attribute, fields can be referenced without needing to be passed explicitly into the format string -- eg, `#[error = "{ident} already declared"] ` will set the error message to `format!("{} already declared", &self.ident)`. Any fields on the struct can be referenced in this way.
Additionally, for any of these attributes, Option fields can be used to only optionally apply the decoration -- for example:
```rust
#[derive(SessionDiagnostic)]
#[code = "E0123"]
struct SomeKindOfError {
...
#[suggestion(message = "informative error message")]
opt_sugg: Option<(Span, Applicability)>
...
}
```
will not emit a suggestion if `opt_sugg` is `None`.
We plan on iterating on this macro further; this PR is a start.
Closes#61132.
r? `@oli-obk`
do not apply DerefMut on union field
This implements the part of [RFC 2514](https://github.com/rust-lang/rfcs/blob/master/text/2514-union-initialization-and-drop.md) about `DerefMut`. Unlike described in the RFC, we only apply this warning specifically when doing `DerefMut` of a `ManuallyDrop` field; that is really the case we are worried about here.
@matthewjasper suggested I patch `convert_place_derefs_to_mutable` and `convert_place_op_to_mutable` for this, but I could not find anything to do in `convert_place_op_to_mutable` and this is sufficient to make the test pass. However, maybe there are some other cases this misses? I have no familiarity with this code.
This is a breaking change *in theory*, if someone used `ManuallyDrop<T>` in a union field and relied on automatic `DerefMut`. But on stable this means `T: Copy`, so the `ManuallyDrop` is rather pointless.
Cc https://github.com/rust-lang/rust/issues/55149
While formatting for user diagnostics used `Display` for all most cases,
some small amount of cases used `Debug` instead. Until now, `Display`
and `Debug` yielded the same output for many types. However, with path
trimming, we want to show a shorter path for the user, these cases need
fixing.
bors
Esteban Küber
Gus Wynn
aticu
Aaron Hill
Tyler Mandry
David Wood
Bastian Kauschke
Matthias Krüger
Bram van den Heuvel
Dylan DPC
kadmin
Caleb Zulawski
LeSeulArtichaut
Dan Aloni
jumbatm
jumbatm
Ralf Jung
mark