Add `must_use` on pointer equality functions
`ptr == ptr` (like all use of `==`) has a similar warning, and these functions are simple convenience wrappers over that.
Correct misleading std::fmt::Binary example (#116165)
Nothing too crazy...
- Add two to the width specifier (so all 32 bits are correctly displayed)
- Pad out the compared string so the assert passes
- Add `// Note` comment highlighting the need for the extra width when using the `#` flag.
The exact contents (and placement?) of the note are, of course, highly bikesheddable.
Partially outline code inside the panic! macro
This outlines code inside the panic! macro in some cases. This is split out from https://github.com/rust-lang/rust/pull/115562 to exclude changes to rustc.
Add "integer square root" method to integer primitive types
For every suffix `N` among `8`, `16`, `32`, `64`, `128` and `size`, this PR adds the methods
```rust
const fn uN::isqrt() -> uN;
const fn iN::isqrt() -> iN;
const fn iN::checked_isqrt() -> Option<iN>;
```
to compute the [integer square root](https://en.wikipedia.org/wiki/Integer_square_root), addressing issue #89273.
The implementation is based on the [base 2 digit-by-digit algorithm](https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Binary_numeral_system_(base_2)) on Wikipedia, which after some benchmarking has proved to be faster than both binary search and Heron's/Newton's method. I haven't had the time to understand and port [this code](http://atoms.alife.co.uk/sqrt/SquareRoot.java) based on lookup tables instead, but I'm not sure whether it's worth complicating such a function this much for relatively little benefit.
fix a comment about assert_receiver_is_total_eq
"a type implements #[deriving]" doesn't make any sense, so I assume they meant "implement `Eq`"? Also the attribute is called `derive`.
error: unresolved link to `std::fmt::Error`
--> library/core/src/fmt/mod.rs:115:52
|
115 | /// This function will return an instance of [`std::fmt::Error`] on error.
|
|
= note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`
ConstParamTy: require Eq as supertrait
As discussed with `@BoxyUwu` [on Zulip](https://rust-lang.zulipchat.com/#narrow/stream/260443-project-const-generics/topic/.60ConstParamTy.60.20and.20.60Eq.60).
We want to say that valtree equality on const generic params agrees with `==`, but that only makes sense if `==` actually exists, hence we should have an appropriate bound. Valtree equality is an equivalence relation, so such a type can always be `Eq` and not just `PartialEq`.
Clarify example in `Pin::new_unchecked` docs
This example in the docs of `Pin::new_unchecked` puzzled me for a relatively long time. Now I understand that it comes down to the difference between dropping the `Pin` vs dropping the pinned value.
I have extended the explanation to highlight this difference. In my opinion it is clearer now, and I hope it helps others understand `Pin` better.
Document panics on unsigned wrapping_div/rem calls (#116063)
Add missing `# Panics` sections to the `uint_impl!` macro, documenting that the `wrapping_rem/div` calls will panic if passed zero.
Call panic_display directly in const_panic_fmt.
`panic_str` just directly calls `panic_display`. The only reason `panic_str` exists, is for a lint to detect an expansion of `panic_2015!(expr)` (which expands to `panic_str`).
It is `panic_display` that is hooked by const-eval, which is the reason we call it here.
Part of https://github.com/rust-lang/rust/issues/116005
r? ``@oli-obk``
