Rustup #15616
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Rustup #15616
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To avoid workspace warnings.
Add lint against integer to pointer transmutes
# `integer_to_ptr_transmutes`
*warn-by-default*
The `integer_to_ptr_transmutes` lint detects integer to pointer transmutes where the resulting pointers are undefined behavior to dereference.
### Example
```rust
fn foo(a: usize) -> *const u8 {
unsafe {
std::mem::transmute::<usize, *const u8>(a)
}
}
```
```
warning: transmuting an integer to a pointer creates a pointer without provenance
--> a.rs:1:9
|
158 | std::mem::transmute::<usize, *const u8>(a)
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: this is dangerous because dereferencing the resulting pointer is undefined behavior
= note: exposed provenance semantics can be used to create a pointer based on some previously exposed provenance
= help: if you truly mean to create a pointer without provenance, use `std::ptr::without_provenance_mut`
= help: for more information about transmute, see <https://doc.rust-lang.org/std/mem/fn.transmute.html#transmutation-between-pointers-and-integers>
= help: for more information about exposed provenance, see <https://doc.rust-lang.org/std/ptr/index.html#exposed-provenance>
= note: `#[warn(integer_to_ptr_transmutes)]` on by default
help: use `std::ptr::with_exposed_provenance` instead to use a previously exposed provenance
|
158 - std::mem::transmute::<usize, *const u8>(a)
158 + std::ptr::with_exposed_provenance::<u8>(a)
|
```
### Explanation
Any attempt to use the resulting pointers are undefined behavior as the resulting pointers won't have any provenance.
Alternatively, `std::ptr::with_exposed_provenance` should be used, as they do not carry the provenance requirement or if the wanting to create pointers without provenance `std::ptr::without_provenance_mut` should be used.
See [std::mem::transmute] in the reference for more details.
[std::mem::transmute]: https://doc.rust-lang.org/std/mem/fn.transmute.html
--------
People are getting tripped up on this, see rust-lang/rust#128409 and rust-lang/rust#141220. There are >90 cases like these on [GitHub search](https://github.com/search?q=lang%3Arust+%2Ftransmute%3A%3A%3Cu%5B0-9%5D*.*%2C+%5C*const%2F&type=code).
Fixes rust-lang#13140
Fixes rust-lang/rust#141220
Fixes rust-lang/rust#145523
`@rustbot` labels +I-lang-nominated +T-lang
cc `@traviscross`
r? compiler
Use unnamed lifetime spans as primary spans for `MISMATCHED_LIFETIME_SYNTAXES` Fixes rust-lang/rust#145772 This PR changes the primary span(s) of the `MISMATCHED_LIFETIME_SYNTAXES` to point to the *unnamed* lifetime spans in both the inputs and *outputs* of the function signature. As reported in rust-lang/rust#145772, this should make it so that IDEs highlight the spans of the actionable part of this lint, rather than just the (possibly named) input spans like they do today. This could be tweaked further perhaps, for example for `fn foo(_: T<'_>) -> T`, we don't need to highlight the elided lifetime if the actionable part is to change only the return type to `T<'_>`, but I think it's improvement on what's here today, so I think that should be follow-up since I think the logic might get a bit hairy. cc ```@shepmaster```
str: Stabilize `round_char_boundary` feature Closes rust-lang/rust#93743 FCP completed rust-lang/rust#93743 (comment)
add span to struct pattern rest (..) Struct pattern rest (`..`) did not retain span information compared to normal fields. This patch adds span information for it. The motivation of this patch comes from when I implemented this PR for Clippy: rust-lang#15000 (comment) It is possible to get the span of the Et cetera in a bit roundabout way, but I thought this would be nicer.
rustbot
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What a nice small sync! |
|
Lintcheck changes for e9810e5
This comment will be updated if you push new changes |
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r? @ghost
changelog: integer-to-pointer-transmutes are now handled by the upstream
integer_to_ptr_transmutesRust lint and no longer by the [useless_transmute] Clippy lint