make is_power_of_two a const function
This makes `is_power_of_two` a const function by using `&` instead of short-circuiting `&&`; Rust supports bitwise `&` for `bool` and short-circuiting is not required in the existing expression.
I don't think this needs a const-hack label as I don't find the changed code less readable, if anything I prefer that it is clearer that short circuiting is not used.
@oli-obk
Inline `{min,max}_value` even in debug builds
I think it is worth to inline `{min,max}_value` even in debug builds.
See this godbolt link: https://godbolt.org/z/-COkVS
use `sign` variable in abs and wrapping_abs methods
This also makes the code easier to understand by hinting at the significance of `self >> ($BITS - 1)`.
Also, now `overflowing_abs` simply uses `wrapping_abs`, which is clearer and avoids a potential performance regression in the LLVM IR.
This PR follows from the discussion from #63786.
r? @eddyb
cc @nikic
This also makes the code easier to understand by hinting at the
significance of `self >> ($BITS - 1)` and by including an explanation
in the comments.
Also, now overflowing_abs simply uses wrapping_abs, which is clearer
and avoids a potential performance regression in the LLVM IR.
Also removes stage1, stage2 cfgs being passed to rustc to ensure that
stage1 and stage2 are only differentiated as a group (i.e., only through
not bootstrap).
This allows types like Option<NonZeroU8> to be used in FFI without triggering the improper_ctypes lint. This works by changing the is_repr_nullable_ptr function to consider an enum E to be FFI-safe if:
- E has no explicit #[repr(...)].
- It only has two variants.
- One of those variants is empty (meaning it has no fields).
- The other variant has only one field.
- That field is one of the following:
- &T
- &mut T
- extern "C" fn
- core::num::NonZero*
- core::ptr::NonNull<T>
- #[repr(transparent)] struct wrapper around one of the types in this list.
- The size of E and its field are both known and are both the same size (implying E is participating in the nonnull optimization).
... on different platforms.
Official rustdoc of
[`usize::to_le_bytes`](https://doc.rust-lang.org/std/primitive.usize.html#method.to_le_bytes)
displays signature
```
pub fn to_ne_bytes(self) -> [u8; 8]
```
which might be misleading: this function returns 4 bytes on 32-bit
systems.
Add a tidy check for files with over 3,000 lines
Files with a large number of lines can cause issues in GitHub (e.g. https://github.com/rust-lang/rust/issues/60015) and also tend to be indicative of opportunities to refactor into less monolithic structures.
This adds a new check to tidy to warn against files that have more than 3,000 lines, as suggested in https://github.com/rust-lang/rust/issues/60015#issuecomment-483868594. (This number was chosen fairly arbitrarily as a reasonable indicator of size.) This check can be ignored with `// ignore-tidy-filelength`.
Existing files with greater than 3,000 lines currently ignore the check, but this helps us spot when files are getting too large. (We might try to split up all files larger than this in the future, as in https://github.com/rust-lang/rust/issues/60015).
Implement saturating_abs() and saturating_neg() functions for signed integer types
Similar to wrapping_abs() / wrapping_neg() functions but saturating at the numeric bounds instead of wrapping around. Complements the existing set of functions with saturation mechanics.
cc #59983
Similar to wrapping_abs() / wrapping_neg() functions but saturating at
the numeric bounds instead of wrapping around. Complements the existing
set of functions with saturation mechanics.
Warn on unused results for operation methods on nums
From a suggestion by @llogiq
Adds a `#[must_use]` attribute to operation methods on integers that take self by value as the first operand and another value as the second. It makes it clear that these methods return the result of the operation instead of mutating `self`, which is the source of a rather embarrassing bug I had in a codebase of mine recently...
As an example:
```rust
struct Int {
value: i64,
}
impl Int {
fn add(&mut self, other: i64) {
self.value.wrapping_add(other);
}
}
```
Will produce a warning like:
```
warning: unused return value of `core::num::<impl i64>::wrapping_add` that must be used
--> src/main.rs:7:7
|
7 | self.value.wrapping_add(other);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: #[warn(unused_must_use)] on by default
= note: this returns the result of the operation, without modifying the original
```
If this is something we're on board with, we could do something similar for `f32` and `f64` too. There are probably other methods on integers that make sense.
Add FromStr impl for NonZero types
This is a WIP implementation because I do have some questions regarding the solution.
Somebody should ping the lang team on this I guess.
Please see the annotations on the code for more details.
Closes#58604
Fix documentation of from_ne_bytes and from_le_bytes
Copypasta mistake, the documentation of `from_ne_bytes` and `from_le_bytes` used the big-endian variant in the example snippets.
Expand docs for `TryFrom` and `TryInto`.
The examples are still lacking for now, both for module docs and for methods/impl's. Will be adding those in further pushes.
Should hopefully resolve the doc concern in #33417 when finished?
