Move `std::sys_common::alloc` to new module `std::sys::common`
6b56603e35/library/std/src/sys_common/mod.rs (L7-L13)
It was my impression that the goal for `std::sys` has changed from extracting it into a separate crate to making std work with features. However the fact remains that there is a lot of interdependence between `sys` and `sys_common`, this is because `sys_common` contains two types of code:
- abstractions over the different platform implementations in `std::sys` (for example [`std::sys_common::mutex`](https://github.com/rust-lang/rust/blob/master/library/std/src/sys_common/mutex.rs))
- code shared between platforms (for example [`std::sys_common::alloc`](https://github.com/rust-lang/rust/blob/master/library/std/src/sys_common/alloc.rs))
This PR attempts to address this by adding a new module `common` to `std::sys` which will contain code shared between platforms, `alloc.rs` in this case but more can be moved over in the future.
LLVM supports many functions from math.h in its IR. Many of these have
single-instruction variants on various platforms. So, let's add them so
std::arch can use them.
Yes, exact comparison is intentional: rounding must always return a
valid integer-equal value, except for inf/NAN.
add lint deref_nullptr detecting when a null ptr is dereferenced
fixes#83856
changelog: add lint that detect code like
```rust
unsafe {
&*core::ptr::null::<i32>()
};
unsafe {
addr_of!(std::ptr::null::<i32>())
};
let x: i32 = unsafe {*core::ptr::null()};
let x: i32 = unsafe {*core::ptr::null_mut()};
unsafe {*(0 as *const i32)};
unsafe {*(core::ptr::null() as *const i32)};
```
```
warning: Dereferencing a null pointer causes undefined behavior
--> src\main.rs:5:26
|
5 | let x: i32 = unsafe {*core::ptr::null()};
| ^^^^^^^^^^^^^^^^^^
| |
| a null pointer is dereferenced
| this code causes undefined behavior when executed
|
= note: `#[warn(deref_nullptr)]` on by default
```
Limitation:
It does not detect code like
```rust
const ZERO: usize = 0;
unsafe {*(ZERO as *const i32)};
```
or code where `0` is not directly a literal
rustdoc: links from items in a trait impl are inconsistent
Depending on where the struct implementing a trait is coming from, or the current page, the items in a trait impl are not linking to the same thing:
|item| trait page, implementors| trait page, implementations on Foreign Types|struct page, trait implementations|
|-|-|-|-|
|function| link to current impl|link to first impl in the list|link to trait def
|default function | not present |not present |link to trait def
|default function with custom impl|link to current impl|link to trait def |link to trait def
|constant| link to current impl|link to trait def |link to trait def
|associated type| link to current impl|link to trait def |link to trait def
||*missing link to trait def*|*function link wrong + missing link to current impl*|*missing link to current impl*|
<details>
<summary>rust code with those cases</summary>
```rust
pub trait MyTrait {
type Assoc;
const VALUE: u32;
fn trait_function(&self);
fn defaulted(&self) {}
fn defaulted_override(&self) {}
}
impl MyTrait for String {
/// will link to trait def
type Assoc = ();
/// will link to trait def
const VALUE: u32 = 5;
/// will link to first foreign implementor
fn trait_function(&self) {}
/// will link to trait def
fn defaulted_override(&self) {}
}
impl MyTrait for Vec<u8> {
/// will link to trait def
type Assoc = ();
/// will link to trait def
const VALUE: u32 = 5;
/// will link to first foreign implementor
fn trait_function(&self) {}
/// will link to trait def
fn defaulted_override(&self) {}
}
impl MyTrait for MyStruct {
/// in trait page, will link to current impl
///
/// in struct page, will link to trait def
type Assoc = bool;
/// in trait page, will link to current impl
///
/// in struct page, will link to trait def
const VALUE: u32 = 20;
/// in trait page, will link to current impl
///
/// in struct page, will link to trait def
fn trait_function(&self) {}
/// in trait page, will link to current impl
///
/// in struct page, will link to trait def
fn defaulted_override(&self) {}
}
pub struct MyStruct;
```
</details>
In this PR, I fixed all links to target the trait definition, and added an anchor-link to the current implementation appearing on mouse hover.
tabs_in_doc_comments: Fix ICE due to char indexing
This is a quick-fix for an ICE in `tabs_in_doc_comments`. The problem
was that we we're indexing into possibly multi-byte characters, such as '位'.
More specifically `get_chunks_of_tabs` was returning indices into
multi-byte characters. Those were passed on to a `Span` creation that
then caused the ICE.
This fix makes sure that we don't return indices that point inside a
multi-byte character. *However*, we are still iterating over unicode
codepoints, not grapheme clusters. So a seemingly single character like y̆ ,
which actually consists of two codepoints, will probably still cause
incorrect spans in the output. But I don't think we handle those cases
anywhere in Clippy currently?
Fixes#5835
changelog: Fix ICE in `tabs_in_doc_comments`
Fix a FP in `missing_const_for_fn`
where a function that calls a standard library function whose constness
is unstable is considered as being able to be a const function. Fixes#5995.
The core change is the move from `rustc_mir::const_eval::is_min_const_fn` to `rustc_mir::const_eval::is_const_fn`. I'm not clear about the difference in their purpose between them so I'm not sure if it's acceptable to call `qualify_min_const_fn::is_min_const_fn` this way now.
---
changelog: `missing_const_for_fn`: No longer lints when an unstably const function is called
Split `is_diagnostic_assoc_item`
changelog: none
* Split `is_diagnostic_assoc_item` into `is_diag_item_method` and `is_diag_trait_item`
* `is_diag_item_method` is a bit more nuanced with the `tcx.type_of(impl_id).ty_adt_def()` step, so it seems better to keep that separate.
* No need to generalize over traits and Adt's since we know which one we want at compile time
* "item" vs. "method" because a trait may have associated items.
* Replaces the usage of the `sym::slice` diagnostic item with the `slice_alloc` lang item. The diagnostic item should be removed from rustc because it is on the `slice_alloc` impl, not slice itself (and it's not needed).
Avoid an `Option<Option<_>>`
By simply swapping the calls to `map` and `and_then` around the complexity of
handling an `Option<Option<_>>` disappears.
`@rustbot` modify labels +C-cleanup +T-compiler
Improve code example for length comparison
Small fix/improvement: it's much safer to check that you're under the length of an array rather than chacking that you're equal to it. It's even more true in case you update the length of the array while iterating.
