Move transmute_undefined_repr back to nursery
There's still open discussion if this lint is ready to be enabled by
default. We want to give us more time to figure this out and prevent
this lint from getting to stable as an enabled-by-default lint.
cc https://github.com/rust-lang/rust-clippy/pull/8432
r? `@Manishearth` `@dtolnay`
I think this is the way to go here. We can re-enable this lint with the next sync, if we should decide to do so. But I would hold of for this release.
We have until Friday (beta branching) to decide if we want to merge this.
There's still open discussion if this lint is ready to be enabled by
default. We want to give us more time to figure this out and prevent
this lint from getting to stable as an enabled-by-default lint.
Specifically, rename the `Const` struct as `ConstS` and re-introduce `Const` as
this:
```
pub struct Const<'tcx>(&'tcx Interned<ConstS>);
```
This now matches `Ty` and `Predicate` more closely, including using
pointer-based `eq` and `hash`.
Notable changes:
- `mk_const` now takes a `ConstS`.
- `Const` was copy, despite being 48 bytes. Now `ConstS` is not, so need a
we need separate arena for it, because we can't use the `Dropless` one any
more.
- Many `&'tcx Const<'tcx>`/`&Const<'tcx>` to `Const<'tcx>` changes
- Many `ct.ty` to `ct.ty()` and `ct.val` to `ct.val()` changes.
- Lots of tedious sigil fiddling.
Specifically, change `Region` from this:
```
pub type Region<'tcx> = &'tcx RegionKind;
```
to this:
```
pub struct Region<'tcx>(&'tcx Interned<RegionKind>);
```
This now matches `Ty` and `Predicate` more closely.
Things to note
- Regions have always been interned, but we haven't been using pointer-based
`Eq` and `Hash`. This is now happening.
- I chose to impl `Deref` for `Region` because it makes pattern matching a lot
nicer, and `Region` can be viewed as just a smart wrapper for `RegionKind`.
- Various methods are moved from `RegionKind` to `Region`.
- There is a lot of tedious sigil changes.
- A couple of types like `HighlightBuilder`, `RegionHighlightMode` now have a
`'tcx` lifetime because they hold a `Ty<'tcx>`, so they can call `mk_region`.
- A couple of test outputs change slightly, I'm not sure why, but the new
outputs are a little better.
Specifically, change `Ty` from this:
```
pub type Ty<'tcx> = &'tcx TyS<'tcx>;
```
to this
```
pub struct Ty<'tcx>(Interned<'tcx, TyS<'tcx>>);
```
There are two benefits to this.
- It's now a first class type, so we can define methods on it. This
means we can move a lot of methods away from `TyS`, leaving `TyS` as a
barely-used type, which is appropriate given that it's not meant to
be used directly.
- The uniqueness requirement is now explicit, via the `Interned` type.
E.g. the pointer-based `Eq` and `Hash` comes from `Interned`, rather
than via `TyS`, which wasn't obvious at all.
Much of this commit is boring churn. The interesting changes are in
these files:
- compiler/rustc_middle/src/arena.rs
- compiler/rustc_middle/src/mir/visit.rs
- compiler/rustc_middle/src/ty/context.rs
- compiler/rustc_middle/src/ty/mod.rs
Specifically:
- Most mentions of `TyS` are removed. It's very much a dumb struct now;
`Ty` has all the smarts.
- `TyS` now has `crate` visibility instead of `pub`.
- `TyS::make_for_test` is removed in favour of the static `BOOL_TY`,
which just works better with the new structure.
- The `Eq`/`Ord`/`Hash` impls are removed from `TyS`. `Interned`s impls
of `Eq`/`Hash` now suffice. `Ord` is now partly on `Interned`
(pointer-based, for the `Equal` case) and partly on `TyS`
(contents-based, for the other cases).
- There are many tedious sigil adjustments, i.e. adding or removing `*`
or `&`. They seem to be unavoidable.
The to_string_in_display lint is renamed to recursive_format_impl
A check is added for the use of self formatted with Display or Debug
inside any format string in the same impl
The to_string_in_display check is kept as is - like in the
format_in_format_args lint
For now only Display and Debug are checked
This could also be extended to other Format traits (Binary, etc.)
Fix `transmute_undefined_repr` with single field `#[repr(C)]` structs
Fixes: #8417
The description has also been made more precise.
changelog: Fix `transmute_undefined_repr` with single field `#[repr(C)]` structs
changelog: Move `transmute_undefined_repr` back to `correctness`
Remove defaultness from ImplItem.
This information is not really used anywhere, except HIR pretty-printing. This makes ImplItem and TraitItem more similar.
Factor out several utils, add `path_def_id`
changelog: none
This is generally an effort to reduce the total number of utils. `path_def_id` is added which I believe is more "cross-cutting" and also complements `path_to_local`. Best reviewed one commit at a time.
Added:
* `path_def_id`
* `path_res`
Removed:
* `is_qpath_def_path`
* `match_any_diagnostic_items`
* `expr_path_res`
* `single_segment_path`
* `differing_macro_contexts`
* `is_ty_param_lang_item`
* `is_ty_param_diagnostic_item`
* `get_qpath_generics`
Renamed:
* `path_to_res` to `def_path_res`
* `get_qpath_generic_tys` to `qpath_generic_tys`
CC `@Jarcho` since this relates to some of your work and you may have input.
warn if we find multiple clippy configs
Fixes#8323
---
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: warn if we find multiple clippy configs
Add lint `transmute_undefined_repr`
Partially implements #3999 and #546
This doesn't consider `enum`s at all right now as those are going to be a pain to deal with. This also allows `#[repr(Rust)]` structs with only one non-zero sized fields. I think those are technically undefined when transmuted.
changelog: Add lint `transmute_undefined_repr`
Add `explicit_write` suggestions for `write!`s with format args
changelog: Add [`explicit_write`] suggestions for `write!`s with format args
Fixes#4542
```rust
writeln!(std::io::stderr(), "macro arg {}", one!()).unwrap();
```
Now suggests:
```
error: use of `writeln!(stderr(), ...).unwrap()`
--> $DIR/explicit_write.rs:36:9
|
LL | writeln!(std::io::stderr(), "macro arg {}", one!()).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `eprintln!("macro arg {}", one!())`
```
---------
r? `@camsteffen` (again, sorry 😛) for the `FormatArgsExpn` change
Before this change `inputs_span` returned a span pointing to just `1` in
```rust
macro_rules! one {
() => { 1 };
}
`writeln!(std::io::stderr(), "macro arg {}", one!()).unwrap();`
```
And the `source_callsite` of that span didn't include the format string, it was just `one!()`
