Rollup merge of #87601 - a1phyr:feature_uint_add_signed, r=kennytm
Add functions to add unsigned and signed integers
This PR adds methods to unsigned integers to add signed integers with good overflow semantics under `#![feature(mixed_integer_ops)]`.
The added API is:
```rust
// `uX` is `u8`, `u16`, `u32`, `u64`,`u128`, `usize`
impl uX {
pub const fn checked_add_signed(self, iX) -> Option<Self>;
pub const fn overflowing_add_signed(self, iX) -> (Self, bool);
pub const fn saturating_add_signed(self, iX) -> Self;
pub const fn wrapping_add_signed(self, iX) -> Self;
}
impl iX {
pub const fn checked_add_unsigned(self, uX) -> Option<Self>;
pub const fn overflowing_add_unsigned(self, uX) -> (Self, bool);
pub const fn saturating_add_unsigned(self, uX) -> Self;
pub const fn wrapping_add_unsigned(self, uX) -> Self;
pub const fn checked_sub_unsigned(self, uX) -> Option<Self>;
pub const fn overflowing_sub_unsigned(self, uX) -> (Self, bool);
pub const fn saturating_sub_unsigned(self, uX) -> Self;
pub const fn wrapping_sub_unsigned(self, uX) -> Self;
}
```
Maybe it would be interesting to also have `add_signed` that panics in debug and wraps in release ?
3209582a87