ea0b6504fa
Add `ascii::Char` (ACP#179) ACP second: https://github.com/rust-lang/libs-team/issues/179#issuecomment-1527900570 New tracking issue: https://github.com/rust-lang/rust/issues/110998 For now this is an `enum` as `@kupiakos` [suggested](https://github.com/rust-lang/libs-team/issues/179#issuecomment-1527959724), with the variants under a different feature flag. There's lots more things that could be added here, and place for further doc updates, but this seems like a plausible starting point PR. I've gone through and put an `as_ascii` next to every `is_ascii`: on `u8`, `char`, `[u8]`, and `str`. As a demonstration, made a commit updating some formatting code to use this: https://github.com/scottmcm/rust/commit/ascii-char-in-fmt (I don't want to include that in this PR, though, because that brings in perf questions that don't exist if this is just adding new unstable APIs.)
The files here use the LLVM FileCheck framework, documented at https://llvm.org/docs/CommandGuide/FileCheck.html.
One extension worth noting is the use of revisions as custom prefixes for FileCheck. If your codegen test has different behavior based on the chosen target or different compiler flags that you want to exercise, you can use a revisions annotation, like so:
// revisions: aaa bbb
// [bbb] compile-flags: --flags-for-bbb
After specifying those variations, you can write different expected, or
explicitly unexpected output by using <prefix>-SAME: and <prefix>-NOT:,
like so:
// CHECK: expected code
// aaa-SAME: emitted-only-for-aaa
// aaa-NOT: emitted-only-for-bbb
// bbb-NOT: emitted-only-for-aaa
// bbb-SAME: emitted-only-for-bbb