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Jonathan Brouwer
932d807e7e
Add `TryFromIntError::kind` method and `IntErrorKind::NotAPowerOfTwo` variant - ACP: rust-lang/libs-team#746 - Tracking issue: rust-lang/rust#153978 This pull request adds `kind` method to [`TryFromIntError`](https://doc.rust-lang.org/core/num/struct.TryFromIntError.html), which outputs the detailed cause of converting an integer failing. This is primarily intended for use in cases where there are multiple causes for failure, such as converting from a large signed integer type to a small signed integer type. At the moment, this method returns [`&IntErrorKind`](https://doc.rust-lang.org/core/num/enum.IntErrorKind.html). This type implements the `Copy` trait and could return `IntErrorKind`, but returns a reference to align with the behavior of [`ParseIntError::kind`](https://doc.rust-lang.org/core/num/struct.ParseIntError.html#method.kind). If it is not necessary to align the behavior of `TryFromIntError::kind` with `ParseIntError::kind`, I'll change this method to return `IntErrorKind`. Before this pull request, `IntErrorKind` was only used by [`ParseIntError`](https://doc.rust-lang.org/core/num/struct.ParseIntError.html), but I changed it to be used by `TryFromIntError` as well, so I updated `IntErrorKind`'s documentation. [`impl TryFrom<usize> for Alignment`](https://doc.rust-lang.org/std/ptr/struct.Alignment.html#impl-TryFrom%3Cusize%3E-for-Alignment) returns `TryFromIntError` as an error if the given value is not a power of two. However, `IntErrorKind` does not have a variant that represents this. So I added the variant `NotAPowerOfTwo` to represent this. For this variant to stabilize, both `try_from_int_error_kind` and `ptr_alignment_type` features must be stabilized.