Lint on invalid usage of `UnsafeCell::raw_get` in reference casting
This PR proposes to take into account `UnsafeCell::raw_get` method call for non-Freeze types for the `invalid_reference_casting` lint.
The goal of this is to catch those kind of invalid reference casting:
```rust
fn as_mut<T>(x: &T) -> &mut T {
unsafe { &mut *std::cell::UnsafeCell::raw_get(x as *const _ as *const _) }
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
}
```
r? `@est31`
refactor(lint): translate `RenamedOrRemovedLint`
I was trying to address <https://github.com/rust-lang/cargo/issues/12495> and found that maybe I should refactor relevant lints a bit.
This PR translates `RenamedOrRemovedLint` into fluent file. To make diagnostic types clearer and easier to organize, this PR splits it into two structs.
The second commit adds lifetime annotations for removing unnecessary clones. If people feel too noisy, we can revert such change.
### Possibly relevant UI tests:
* `tests/ui/lint-removed*`
* `tests/ui/lint-renamed*`
* `tests/ui/rustdoc-renamed.rs`
* `tests/rustdoc-ui/lints/unknown-renamed-lints.rs`
Add support for `ptr::write`s for the `invalid_reference_casting` lint
This PR adds support for `ptr::write` and others for the `invalid_reference_casting` lint.
Detecting instances where instead of using the deref (`*`) operator to assign someone uses `ptr::write`, `ptr::write_unaligned` or `ptr::write_volatile`.
```rust
let data_len = 5u64;
std::ptr::write(
std::mem::transmute::<*const u64, *mut u64>(&data_len),
new_data_len,
);
```
r? ``@est31``
Warn on elided lifetimes in associated constants (`ELIDED_LIFETIMES_IN_ASSOCIATED_CONSTANT`)
Elided lifetimes in associated constants (in impls) erroneously resolve to fresh lifetime parameters on the impl since #97313. This is not correct behavior (see #38831).
I originally opened #114716 to fix this, but given the time that has passed, the crater results seem pretty bad: https://github.com/rust-lang/rust/pull/114716#issuecomment-1682091952
This PR alternatively implements a lint against this behavior, and I'm hoping to bump this to deny in a few versions.
Also consider `mem::transmute` with the `invalid_reference_casting` lint
This PR extend the `invalid_reference_casting` lint with regard to the `std::mem::transmute` function.
```
error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
--> $DIR/reference_casting.rs:27:16
|
LL | let _num = &mut *std::mem::transmute::<_, *mut i32>(&num);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
```
*I encourage anyone reviewing this PR to do so [without whitespaces](https://github.blog/2011-10-21-github-secrets/#whitespace).*
rustc: Move `features` from `Session` to `GlobalCtxt`
Removes one more piece of mutable state.
Follow up to #114622.
The rule I used for passing feature in function signatures:
- if a crate already depends on `rustc_middle`, then `Session` is replaced with `TyCtxt`
- otherwise session and features are passed as a pair `sess: &Session, features: &Features`
The code in `rustc_lint` is ultimately used for implementing a trait from `rustc_expand`, so it also doesn't use tcx despite the dependency on `rustc_middle`.
Avoid invalid NaN lint machine-applicable suggestion in const context
This PR removes the machine-applicable suggestion in const context for the `invalid_nan_comparision` lint ~~and replace it with a simple help~~.
Fixes https://github.com/rust-lang/rust/issues/114471
Convert builtin "global" late lints to run per module
The compiler currently has 4 non-incremental lints:
1. `clashing_extern_declarations`;
2. `missing_debug_implementations`;
3. ~`unnameable_test_items`;~ changed by https://github.com/rust-lang/rust/pull/114414
4. `missing_docs`.
Non-incremental lints get reexecuted for each compilation, which is slow. Moreover, those lints are allow-by-default, so run for nothing most of the time. This PR attempts to make them more incremental-friendly.
`clashing_extern_declarations` is moved to a standalone query.
`missing_debug_implementation` can use `non_blanket_impls_for_ty` instead of recomputing it.
`missing_docs` is harder as it needs to track if there is a `doc(hidden)` module surrounding. I hack around this using the lint level engine. That's easy to implement and allows to re-enable the lint for a re-exported module, while a more proper solution would reuse the same device as `unnameable_test_items`.
Add separate feature gate for async fn track caller
This patch adds a feature gate `async_fn_track_caller` that is separate from `closure_track_caller`. This is to allow enabling `async_fn_track_caller` separately.
Fixes#110009
Improve spans for indexing expressions
fixes#114388
Indexing is similar to method calls in having an arbitrary left-hand-side and then something on the right, which is the main part of the expression. Method calls already have a span for that right part, but indexing does not. This means that long method chains that use indexing have really bad spans, especially when the indexing panics and that span in coverted into a panic location.
This does the same thing as method calls for the AST and HIR, storing an extra span which is then put into the `fn_span` field in THIR.
r? compiler-errors
Indexing is similar to method calls in having an arbitrary
left-hand-side and then something on the right, which is the main part
of the expression. Method calls already have a span for that right part,
but indexing does not. This means that long method chains that use
indexing have really bad spans, especially when the indexing panics and
that span in coverted into a panic location.
This does the same thing as method calls for the AST and HIR, storing an
extra span which is then put into the `fn_span` field in THIR.
Add `internal_features` lint
Implements https://github.com/rust-lang/compiler-team/issues/596
Also requires some more test blessing for codegen tests etc
`@jyn514` had the idea of just `allow`ing the lint by default in the test suite. I'm not sure whether this is a good idea, but it's definitely one worth considering. Additional input encouraged.
Expand, rename and improve `incorrect_fn_null_checks` lint
This PR,
- firstly, expand the lint by now linting on references
- secondly, it renames the lint `incorrect_fn_null_checks` -> `useless_ptr_null_checks`
- and thirdly it improves the lint by catching `ptr::from_mut`, `ptr::from_ref`, as well as `<*mut _>::cast` and `<*const _>::cast_mut`
Fixes https://github.com/rust-lang/rust/issues/113601
cc ```@est31```
It lints against features that are inteded to be internal to the
compiler and standard library. Implements MCP #596.
We allow `internal_features` in the standard library and compiler as those
use many features and this _is_ the standard library from the "internal to the compiler and
standard library" after all.
Marking some features as internal wasn't exactly the most scientific approach, I just marked some
mostly obvious features. While there is a categorization in the macro,
it's not very well upheld (should probably be fixed in another PR).
We always pass `-Ainternal_features` in the testsuite
About 400 UI tests and several other tests use internal features.
Instead of throwing the attribute on each one, just always allow them.
There's nothing wrong with testing internal features^^
This patch adds a feature gate `async_fn_track_caller` that is separate from `closure_track_caller`. This is to allow enabling `async_fn_track_caller` separately.
Fixes#110009
Improve `invalid_reference_casting` lint
This PR is a follow-up to https://github.com/rust-lang/rust/pull/111567 and https://github.com/rust-lang/rust/pull/113422.
This PR does multiple things:
- First it adds support for deferred de-reference, the goal is to support code like this, where the casting and de-reference are not done on the same expression
```rust
let myself = self as *const Self as *mut Self;
*myself = Self::Ready(value);
```
- Second it does not lint anymore on SB/TB UB code by only checking assignments (`=`, `+=`, ...) and creation of mutable references `&mut *`
- Thirdly it greatly improves the diagnostics in particular for cast from `&mut` to `&mut` or assignments
- ~~And lastly it renames the lint from `cast_ref_to_mut` to `invalid_reference_casting` which is more consistent with the ["rules"](https://github.com/rust-lang/rust-clippy/issues/2845) and also more consistent with what the lint checks~~ *https://github.com/rust-lang/rust/pull/113422*
This PR is best reviewed commit by commit.
r? compiler
Rename and allow `cast_ref_to_mut` lint
This PR is a small subset of https://github.com/rust-lang/rust/pull/112431, that is the renaming of the lint (`cast_ref_to_mut` -> `invalid_reference_casting`).
BUT also temporarily change the default level of the lint from deny-by-default to allow-by-default until https://github.com/rust-lang/rust/pull/112431 is merged.
r? `@Nilstrieb`
fix(resolve): update the ambiguity glob binding as warning recursively
Fixes#47525Fixes#56593, but `issue-56593-2.rs` is not fixed to ensure backward compatibility.
Fixes#98467Fixes#105235Fixes#112713
This PR had added a field called `warn_ambiguous` in `NameBinding` which is only for back compatibly reason and used for lint.
More details: https://github.com/rust-lang/rust/pull/112743
r? `@petrochenkov`
lint/ctypes: fix `()` return type checks
Fixes#113436.
`()` is normally FFI-unsafe, but is FFI-safe when used as a return type. It is also desirable that a transparent newtype for `()` is FFI-safe when used as a return type.
In order to support this, when a type was deemed FFI-unsafe, because of a `()` type, and was used in return type - then the type was considered FFI-safe. However, this was the wrong approach - it didn't check that the `()` was part of a transparent newtype! The consequence of this is that the presence of a `()` type in a more complex return type would make it the entire type be considered safe (as long as the `()` type was the first that the lint found) - which is obviously incorrect.
Instead, this logic is removed, and after [consultation with t-lang](https://github.com/rust-lang/rust/issues/113436#issuecomment-1640756721), I've fixed the bugs and inconsistencies and made `()` FFI-safe within types.
I also refactor a function, but that's not too exciting.
Now that this lint runs on any external-ABI fn-ptr, normalization won't
always succeed, so use `try_normalize_erasing_regions` instead.
Signed-off-by: David Wood <david@davidtw.co>
Consider `()` within types to be FFI-safe, and `()` to be FFI-safe as a
return type (incl. when in a transparent newtype).
Signed-off-by: David Wood <david@davidtw.co>
`()` is normally FFI-unsafe, but is FFI-safe when used as a return type.
It is also desirable that a transparent newtype for `()` is FFI-safe when
used as a return type.
In order to support this, when an type was deemed FFI-unsafe, because of
a `()` type, and was used in return type - then the type was considered
FFI-safe. However, this was the wrong approach - it didn't check that the
`()` was part of a transparent newtype! The consequence of this is that
the presence of a `()` type in a more complex return type would make it
the entire type be considered safe (as long as the `()` type was the
first that the lint found) - which is obviously incorrect.
Instead, this logic is removed, and a unit return type or a transparent
wrapper around a unit is checked for directly for functions and fn-ptrs.
Signed-off-by: David Wood <david@davidtw.co>
Fix removal span calculation of `unused_qualifications` suggestion
Given a path such as `std::ops::Index<str>`, calculate the unnecessary qualification removal span by computing the beginning of the entire span until the ident span of the last path segment, which handles generic arguments and lifetime arguments in the last path segment. Previous logic only kept the ident span of the last path segment which is incorrect.
Closes#113808.
Uplift `clippy::fn_null_check` lint
This PR aims at uplifting the `clippy::fn_null_check` lint into rustc.
## `incorrect_fn_null_checks`
(warn-by-default)
The `incorrect_fn_null_checks` lint checks for expression that checks if a function pointer is null.
### Example
```rust
let fn_ptr: fn() = /* somehow obtained nullable function pointer */
if (fn_ptr as *const ()).is_null() { /* ... */ }
```
### Explanation
Function pointers are assumed to be non-null, checking for their nullity is incorrect.
-----
Mostly followed the instructions for uplifting a clippy lint described here: https://github.com/rust-lang/rust/pull/99696#pullrequestreview-1134072751
`@rustbot` label: +I-lang-nominated
r? compiler
