Guillaume Boisseau f70f13a1d3
Rollup merge of #120932 - RalfJung:mut-ptr-to-static, r=oli-obk
const_mut_refs: allow mutable pointers to statics

Fixes https://github.com/rust-lang/rust/issues/118447

Writing this PR became a bit messy, see [Zulip](https://rust-lang.zulipchat.com/#narrow/stream/146212-t-compiler.2Fconst-eval/topic/Statics.20pointing.20to.20interior.20mutable.20statics) for some of my journey.^^ Turns out there was a long-standing bug in our qualif logic that led to us incorrectly classifying certain places as "no interior mut" when they actually had interior mut. Due to that the `const_refs_to_cell` feature gate was required far less often than it otherwise would, e.g. in [this code](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=9e0c042c451b3d11d64dd6263679a164). Fixing this however would be a massive breaking change all over libcore and likely the wider ecosystem. So I also changed the const-checking logic to just not require the feature gate for the affected cases. While doing so I discovered a bunch of logic that is not explained and that I could not explain. However I think stabilizing some const-eval feature will make most of that logic inconsequential so I just added some FIXMEs and left it at that.

r? `@oli-obk`
2024-02-17 11:23:03 +01:00
..
2024-02-01 03:31:03 +00:00
2024-02-17 10:44:46 +05:30
2024-02-07 10:42:01 +08:00
2024-02-07 10:42:01 +08:00

UI Tests

This folder contains rustc's UI tests.

Test Directives (Headers)

Typically, a UI test will have some test directives / headers which are special comments that tell compiletest how to build and intepret a test.

As part of an on-going effort to rewrite compiletest (see https://github.com/rust-lang/compiler-team/issues/536), a major change proposal to change legacy compiletest-style headers // <directive> to ui_test-style headers //@ <directive> was accepted (see https://github.com/rust-lang/compiler-team/issues/512.

An example directive is ignore-test. In legacy compiletest style, the header would be written as

// ignore-test

but in ui_test style, the header would be written as

//@ ignore-test

compiletest is changed to accept only //@ directives for UI tests (currently), and will reject and report an error if it encounters any comments // <content> that may be parsed as an legacy compiletest-style test header. To fix this, you should migrate to the ui_test-style header //@ <content>.