Let `qualify_min_const_fn` deal with drop terminators
Fixes#12677
The `method_accepts_droppable` check that was there seemed overly conservative.
> Returns true if any of the method parameters is a type that implements `Drop`.
> The method can't be made const then, because `drop` can't be const-evaluated.
Accepting parameters that implement `Drop` should still be fine as long as the parameter isn't actually dropped, as is the case in the linked issue where the droppable is moved into the return place. This more accurate analysis ("is there a `drop` terminator") is already done by `qualify_min_const_fn` [here](f5e250180c/clippy_utils/src/qualify_min_const_fn.rs (L298)), so I don't think this additional check is really necessary?
Fixing the other, second case in the linked issue was only slightly more involved, since `Vec::new()` is a function call that has the ability to panic, so there must be a `drop()` terminator for cleanup, however we should be able to freely ignore that. [Const checking ignores cleanup blocks](https://github.com/rust-lang/rust/blob/master/compiler/rustc_const_eval/src/transform/check_consts/check.rs#L382-L388), so we should, too?
r? `@Jarcho`
----
changelog: [`missing_const_for_fn`]: continue linting on fns with parameters implementing `Drop` if they're not actually dropped
Make `for_each_expr` visit closures by default, rename the old version `for_each_expr_without_closures`
A lot of the time `for_each_expr` is picked when closures should be visited so I think it makes sense for this to be the default with the alternative available for when you don't need to visit them.
The first commit renames `for_each_expr` to `for_each_expr_without_closures` and `for_each_expr_with_closures` to `for_each_expr`
The second commit switches a few uses that I caught over to include closures to fix a few bugs
changelog: none
Handle const effects inherited from parent correctly in `type_certainty`
This fixes a (debug) ICE in `type_certainty` that happened in the [k256 crate]. (I'm sure you can also specifically construct an edge test case that will run into type_certainty false positives visible outside of debug builds from this bug)
<details>
<summary>Minimal ICE repro</summary>
```rs
use std::ops::Add;
Add::add(1_i32, 1).add(i32::MIN);
```
</details>
The subtraction here overflowed:
436675b477/clippy_utils/src/ty/type_certainty/mod.rs (L209)
... when we have something like `Add::add` where `add` fn has 0 generic params but the `host_effect_index` is `Some(2)` (inherited from the parent generics, the const trait `Add`), and we end up executing `0 - 1`.
(Even if the own generics weren't empty and we didn't overflow, this would still be wrong because it would assume that a trait method with 1 generic parameter didn't have any generics).
So, *only* exclude the "host" generic parameter if it's actually bound by the own generics
changelog: none
[k256 crate]: https://github.com/RustCrypto/elliptic-curves/tree/master/k256
[perf] Delay the construction of early lint diag structs
Attacks some of the perf regressions from https://github.com/rust-lang/rust/pull/124417#issuecomment-2123700666.
See individual commits for details. The first three commits are not strictly necessary.
However, the 2nd one (06bc4fc67145e3a7be9b5a2cf2b5968cef36e587, *Remove `LintDiagnostic::msg`*) makes the main change way nicer to implement.
It's also pretty sweet on its own if I may say so myself.
* instead simply set the primary message inside the lint decorator functions
* it used to be this way before [#]101986 which introduced `msg` to prevent
good path delayed bugs (which no longer exist) from firing under certain
circumstances when lints were suppressed / silenced
* this is no longer necessary for various reasons I presume
* it shaves off complexity and makes further changes easier to implement
Rename Unsafe to Safety
Alternative to #124455, which is to just have one Safety enum to use everywhere, this opens the posibility of adding `ast::Safety::Safe` that's useful for unsafe extern blocks.
This leaves us today with:
```rust
enum ast::Safety {
Unsafe(Span),
Default,
// Safe (going to be added for unsafe extern blocks)
}
enum hir::Safety {
Unsafe,
Safe,
}
```
We would convert from `ast::Safety::Default` into the right Safety level according the context.
make sure the msrv for `const_raw_ptr_deref` is met when linting [`missing_const_for_fn`]
fixes: #8864
---
changelog: make sure the msrv for `const_ptr_deref` is met when linting [`missing_const_for_fn`]
`InferCtxt::next_{ty,const}_var*` all take an origin, but the
`param_def_id` is almost always `None`. This commit changes them to just
take a `Span` and build the origin within the method, and adds new
methods for the rare cases where `param_def_id` might not be `None`.
This avoids a lot of tedious origin building.
Specifically:
- next_ty_var{,_id_in_universe,_in_universe}: now take `Span` instead of
`TypeVariableOrigin`
- next_ty_var_with_origin: added
- next_const_var{,_in_universe}: takes Span instead of ConstVariableOrigin
- next_const_var_with_origin: added
- next_region_var, next_region_var_in_universe: these are unchanged,
still take RegionVariableOrigin
The API inconsistency (ty/const vs region) seems worth it for the
large conciseness improvements.
Remove braces when fixing a nested use tree into a single item
[Back in 2019](https://github.com/rust-lang/rust/pull/56645) I added rustfix support for the `unused_imports` lint, to automatically remove them when running `cargo fix`. For the most part this worked great, but when removing all but one childs of a nested use tree it turned `use foo::{Unused, Used}` into `use foo::{Used}`. This is slightly annoying, because it then requires you to run `rustfmt` to get `use foo::Used`.
This PR automatically removes braces and the surrouding whitespace when all but one child of a nested use tree are unused. To get it done I had to add the span of the nested use tree to the AST, and refactor a bit the code I wrote back then.
A thing I noticed is, there doesn't seem to be any `//@ run-rustfix` test for fixing the `unused_imports` lint. I created a test in `tests/suggestions` (is that the right directory?) that for now tests just what I added in the PR. I can followup in a separate PR to add more tests for fixing `unused_lints`.
This PR is best reviewed commit-by-commit.
Some hir cleanups
It seemed odd to not put `AnonConst` in the arena, compared with the other types that we did put into an arena. This way we can also give it a `Span` without growing a lot of other HIR data structures because of the extra field.
r? compiler
Fix `FormatArgs` storage when `-Zthreads` > 1
Fixes#11886
The initial way I thought of was a little gross so I never opened a PR for it, I thought of a nicer way today that no longer involves any `thread_local`s or `static`s
`rustc_data_strucutres::sync::{Lrc, OnceLock}` implement `DynSend` + `DynSync` so we can pass them to the lint passes that need the storage
changelog: none
r? `@flip1995`
