Add `known-bug` tests for all(?) I-unsound issues

[jackh726]

I'll come back at some point and create an actual list. However, we should aim to add known-bug tests (or work to finding MCVEs) for all the I-unsound issues.

The list of issues remaining: https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AI-unsound+-label%3AS-bug-has-test+

The list of completed issues: https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AI-unsound+label%3AS-bug-has-test+

[sladyn98]

@jackh726 I would like to give this a shot, any hints on where I could begin

[jackh726]

@sladyn98 sure!

Okay, so we have a concept of known-bug tests. Here's an example: https://github.com/rust-lang/rust/blob/18a6d911caba59605eb03db1452848a85d2e5879/tests/ui/coherence/coherence-overlap-negative-impls.rs

Note the // known-bug: #101350 at the top. There is also // check-pass, which means that this test currently passes under during check (though that test shouldn't pass, hence the known-bug)

The goal for this issue is to go through the open I-unsound issues (https://github.com/rust-lang/rust/issues?page=1&q=is%3Aopen+is%3Aissue+label%3AI-unsound), identify a minimal reproduction that shouldn't pass, but does, and add a known-bug test for each one.

Nearly all of the issues should have a minimal repro in the comments somewhere, so I would start with those. Tests should go in src/test/ui in an appropriate directory. Test names should likely be meaningful compared to the open issue. Any comments at the top of the file briefly explaining the problem would also be helpful.

Let me know if that helps!

[sladyn98]

#105084
I found this issue, and planning to a PR with a known test bug

[KenCox94]

is there anything a new contributor can do for this? any help still needed @sladyn98 @jackh726

[jackh726]

My previous comment still applies; there haven't been any PRs opened for this.

If anything is confusing, please let me know.

[gburgessiv]

If it helps, the listing I was able to scrape is:

• Collisions in type_id #10389 (maybe a no-go? we'd need to test for TypeId collisions)
• Investigate how LLVM deals with huge stack frames #18072
• Implied bounds on nested references + variance = soundness hole #25860
• set_var/remove_var are unsound in combination with C code that reads the environment #27970
• #[no_mangle] is unsafe in the presence of name collisions #28179
• Tracking issue for specialization (RFC 1210) #31844
• Specialization and lifetime dispatch #40582
• Extend stack probe support to non-tier-1 platforms, and clarify policy for mitigating LLVM-dependent unsafety #43241
• ill-typed unused FFI declarations can cause UB #46188
• Panics in destructors can cause the return value to be leaked #47949
• Constants can contain references that are not Sync #49206
• Keeping references to #[thread_local] statics is allowed across yields. #49682
• Trait objects can call nonexistent concrete methods #50781
• Abort instead of unwinding past FFI functions #52652
• repr(simd) is unsound in C FFI #53346
• Coherence can be bypassed by an indirect impl for a trait object #57893
• Resolve unsound interaction between noalias and self-referential data (incl. generators, async fn) #63818
• -C target-feature/-C target-cpu are unsound #64609
• std::process::Command doesn't follow Unix signal safety in forked child #64718
• Switching to opt-level=z on i686-windows-msvc triggers STATUS_ACCESS_VIOLATION #67497
• Pin is unsound due to transitive effects of CoerceUnsized #68015
• Statics don't support alignments larger than the page size #70022
• Locals aligned to greater than page size can cause unsound behavior #70143
• unsized_locals fails to uphold alignment requirements #71416
• Comparing to infinity is buggy on x87 #72327
• error: could not compile gkrust since Rust 1.43 on SPARC Solaris #74551
• negative_impls and auto_traits experimental features allow trait impls to overlap #74629
• AVR: Miscompilation with Trait Object in Option #74743
• #[link_section] is unsound on Harvard architectures #76507
• With min_specialization enabled, an incomplete impl for a non-static type will delegate method calls to a less-specific impl with a 'static bound #79457
• Miscompilation of AVX2 code under --release #79865
• rustc has wrong signature for C function with 16-byte aligned stack argument in x86_64 Linux #80127
• Unsoundness in type checking of trait impls. Differences in implied lifetime bounds are not considered. #80176
• Accessing DST field of packed struct calculates the wrong field address #80925
• repr(C) on MSVC targets does not always match MSVC type layout when ZST are involved #81996
• Regressions with large (2-4GB) stack arrays on large stacks #83060
• 'static closures/FnDefs/futures with non-'static return type are unsound #84366
• Functions, closures, and HRTB-trait-objects can implement traits such that validity of associated types is never checked. #84533
• HRTB on subtrait unsoundly provides HTRB on supertrait with weaker implied bounds #84591
• auto trait candidate selection is unsound #84857
• A Pin unsoundness involving an impl DerefMut for Pin<&dyn LocalTrait> #85099
• SpecExtend for TrustedLen is unsound #89948
• TypeId exposes equality-by-subtyping vs normal-form-syntactic-equality unsoundness. #97156
• Unsoundness due to where clauses not checked for well-formedness #98117
• orphan check incorrectly handles projections #99554
• Normalization can skip WF #100041
• implied bounds from projections in impl header can be unsound #100051
• LLVM miscompiles large stack allocations #100914
• Incorrect handling of lateout pairs in inline asm #101346
• relating projection substs is unsound during coherence #102048
• extern "C" functions don't generate the same IR definitions as clang on x86, causing problems with cross-language LTO #102174
• prevent negative impl cycles #102678
• function type params are not checked for well-formedness #104005
• Box syntax and generator_clone can lead to double free #105084
• Arguments of an impl method may have stronger implied bounds than trait method  #105295
• specialization: default items completely drop candidates instead of ambiguity #105782
• occurs check with aliases results in error, not ambiguity #105787
• Miscompilation: Equal pointers comparing as unequal #107975
• TAIT shouldn't constrain impl generics #108425

rging for the list of I-Unsound issues makes it seem that there're no tests for any of these ATM, so I left them unpopulated. I added a few tests while I was in the area, which I'll build a PR for now. :)