Implicit deref patterns allow previously ill-typed programs. Make sure
they're still ill-typed without the feature gate. I've thrown in a test
for `deref!(_)` too, though it seems it refers to `deref_patterns` as a
library feature.
The place previously used here was that of the temporary holding the
reference returned by `Deref::deref` or `DerefMut::deref_mut`. However,
since the inner pattern of `deref!(inner)` expects the deref-target type
itself, this would ICE when that type was inspected (e.g. by the EUV
case for slice patterns). This adds a deref projection to fix that.
Since current in-tree consumers of EUV (upvar inference and clippy)
don't care about Rvalues, the place could be simplified to
`self.cat_rvalue(pat.hir_id, self.pat_ty_adjusted(subpat)?)` to save
some cycles. I personally find EUV to be a bit fragile, so I've opted
for pedantic correctness. Maybe a `HACK` comment would suffice though?
```
error[E0614]: type `(..., ..., ..., ...)` cannot be dereferenced
--> $DIR/long-E0614.rs:10:5
|
LL | *x;
| ^^ can't be dereferenced
|
= note: the full name for the type has been written to '$TEST_BUILD_DIR/$FILE.long-type-hash.txt'
= note: consider using `--verbose` to print the full type name to the console
```
My reasoning: the ruleset implemented by the same feature gate in
Edition 2024 always tries to eat the inherited reference first. For
consistency, it makes sense to me to say across all editions that users
should consider the inherited reference's mutability when wondering if a
`&mut` pattern will type.
Pattern Migration 2024: fix incorrect messages/suggestions when errors arise in macro expansions
See the diff between the two commits for how this affected the error message and suggestion. In order to decide how to format those, the pattern migration diagnostic keeps track of which parts of the user's pattern cause problems in Edition 2024. However, it neglected to do some of this bookkeeping when pointing to macro expansion sites. This fixes that.
```
error[E0610]: `{integer}` is a primitive type and therefore doesn't have fields
--> $DIR/attempted-access-non-fatal.rs:7:15
|
LL | let _ = 2.l;
| ^
|
help: if intended to be a floating point literal, consider adding a `0` after the period and a `f64` suffix
|
LL - let _ = 2.l;
LL + let _ = 2.0f64;
|
```
Pattern Migration 2024: try to suggest eliding redundant binding modifiers
This is based on #136475. Only the last commit is new.
This is a simpler, more restrictive alternative to #136496, meant to partially address #136047. If a pattern can be migrated to Rust 2024 solely by removing redundant binding modifiers, this will make that suggestion; otherwise, it uses the old suggestion of making the pattern fully explicit.
Relevant tracking issue: #131414
``@rustbot`` label A-diagnostics A-patterns A-edition-2024
r? ``@Nadrieril``
Most of these are meant to test possible future improvements, but since
they cover cases the existing test suite didn't, I figure including them
now may be helpful.
This aligns the main error message a bit more with the phrasing in the
Edition Guide and provides a bit more information on the labels to
(hopefully!) aid in understanding.
