Add test for unknown_lints from another file.
This adds a test for #84936 which was incidentally fixed via #97266. It is a strange issue where `#![allow(unknown_lints)]` at the crate root was not applying to unknown lints that fired in a non-inline-module. I did not dig further into how #97266 fixed it, but I did verify it. I couldn't find any existing tests which did anything similar.
Closes#84936
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).*
Respect `#[expect]` the same way `#[allow]` is with the `dead_code` lint
This PR makes the `#[expect]` attribute being respected in the same way the `#[allow]` attribute is with the `dead_code` lint.
The fix is much more involved than I would have liked (and it's not because I didn't tried!), because the implementation took advantage of the fact that firing a lint in a allow context is a nop (for the user, as the lint is suppressed) to not fire-it at all.
And will it's fine for `#[allow]`, it definitively isn't for `#[expect]`, as the presence and absence of the lint is significant. So a big part of the PR is just adding the context information of whenever an item is on the worklist because of an `[allow]`/`#[expect]` or not.
Fixes https://github.com/rust-lang/rust/issues/114557
Make `unconditional_recursion` warning detect recursive drops
Closes#55388
Also closes#50049 unless we want to keep it for the second example which this PR does not solve, but I think it is better to track that work in #57965.
r? `@oli-obk` since you are the mentor for #55388
Unresolved questions:
- [x] There are two false positives that must be fixed before merging (see diff). I suspect the best way to solve them is to perform analysis after drop elaboration instead of before, as now, but I have not explored that any further yet. Could that be an option? **Answer:** Yes, that solved the problem.
`@rustbot` label +T-compiler +C-enhancement +A-lint
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`.
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.
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```
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`
Add regression test for `--cap-lints allow` and trait bounds warning
Closes#43134
I have verified that the test fails if stderr begins to contain output by making sure the test fails when I add
eprintln!("some output on stderr");
to the compiler (I added it to `fn build_session()`).
I have verified that the test fails if stderr begins to contain output
by making sure the test fails when I add
eprintln!("some output on stderr");
to the compiler (I added it to `fn build_session()`).
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.
The warning can be reproduced with 1.63 but not with 1.64.
$ rustc +1.63 tests/ui/lint/unused/const-local-var.rs
warning: constant `F` is never used
--> tests/ui/lint/unused/const-local-var.rs:14:9
|
14 | const F: i32 = 2;
| ^^^^^^^^^^^^^^^^^
|
= note: `#[warn(dead_code)]` on by default
$ rustc +1.64 tests/ui/lint/unused/const-local-var.rs
Add a regression test to prevent the problem from re-appearing.
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>
(re-)tighten sourceinfo span of adjustments in MIR
Diagnostics rely on the spans of MIR statements being (approximately) correct in order to give suggestions relative to that span (i.e. `shrink_to_hi` and `shrink_to_lo`).
I discovered that we're *intentionally* lowering THIR exprs with their parent expr's span if they come from adjustments that are due to a parent expression. While I understand why that may be desirable to demonstrate the relationship of an adjustment and the expression that requires it, it leads to
1. very verbose borrowck output
2. incorrect spans for suggestions
Some diagnostics get around that by giving suggestions relative to other spans we've collected during MIR lowering, such as the span of the method's identifier (e.g. `name` in `.name()`), but this doesn't work too well when things come from desugaring.
I assume it also has lead to numerous tweaks and complications to diagnostics code down the road, which this PR doesn't necessarily aim to fix but may open the gates to fixing later... The last three commits are simplifications due to the fact that we can assume that the move span actually points to what is being moved (and a test).
This regressed in #89110, which was debated somewhat in #90286. cc `@Aaron1011` who originally made this change.
r? diagnostics
Fixes#113547Fixes#111016
