Future incompatibility warning `unsupported_fn_ptr_calling_conventions`: Also warn in dependencies #135767

tdittr · 2025-01-20T12:26:20Z

Tracking issue: #130260

As discussed in the previous PR now the future incompatibility warning is enabled in dependencies.

The warning was added in 1.83, while this change will get into stable in 1.86, which gives crate authors three versions to fix the warning.

r? compiler-errors

compiler-errors · 2025-01-20T13:05:42Z

@rustbot label: +I-lang-nominated +I-easy-decision

compiler-errors · 2025-01-23T18:12:48Z

Looks good to me but waiting on team approval

traviscross · 2025-02-05T16:42:43Z

@rfcbot fcp merge

rfcbot · 2025-02-05T16:42:46Z

Team member @traviscross has proposed to merge this. The next step is review by the rest of the tagged team members:

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

cc @rust-lang/lang-advisors: FCP proposed for lang, please feel free to register concerns.
See this document for info about what commands tagged team members can give me.

tmandry · 2025-02-05T16:43:23Z

@rfcbot reviewed

nikomatsakis · 2025-02-05T16:43:32Z

@rfcbot reviewed

As we decided in #128784, I think it makes sense to either accept invalid ABIs on fn-definitions and fn-pointers (but hard error on calls) or forbid them everywhere. Given that we already forbid them on definitions, this seems fine, we can always change if desired.

rfcbot · 2025-02-05T16:43:58Z

🔔 This is now entering its final comment period, as per the review above. 🔔

compiler-errors · 2025-02-05T16:47:49Z

r=me when FCP is over

bors · 2025-02-12T13:27:26Z

☔ The latest upstream changes (presumably #136897) made this pull request unmergeable. Please resolve the merge conflicts.

rfcbot · 2025-02-15T16:46:34Z

The final comment period, with a disposition to merge, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

This will be merged soon.

jieyouxu · 2025-03-01T10:57:57Z

#137599 merged, the tests probably need a rebless.
@rustbot label: -S-blocked
@rustbot author

This was left to only warn in the current crate to give users a chance to update their code. Now for 1.86 we also warn users depending on those crates.

Otherwise this test will include a future incompatibility warning on some targets but not others.

tdittr · 2025-03-03T08:05:57Z

No problem, indeed needed a re-bless.

@rustbot ready

bjorn3 · 2025-03-03T10:50:05Z

@bors r=compiler-errors

bors · 2025-03-03T10:50:08Z

📌 Commit 6657aa9 has been approved by compiler-errors

It is now in the queue for this repository.

bors · 2025-03-03T10:50:08Z

🌲 The tree is currently closed for pull requests below priority 100. This pull request will be tested once the tree is reopened.

…iaskrgr Rollup of 12 pull requests Successful merges: - rust-lang#135767 (Future incompatibility warning `unsupported_fn_ptr_calling_conventions`: Also warn in dependencies) - rust-lang#137852 (Remove layouting dead code for non-array SIMD types.) - rust-lang#137863 (Fix pretty printing of unsafe binders) - rust-lang#137882 (do not build additional stage on compiler paths) - rust-lang#137894 (Revert "store ScalarPair via memset when one side is undef and the other side can be memset") - rust-lang#137902 (Make `ast::TokenKind` more like `lexer::TokenKind`) - rust-lang#137921 (Subtree update of `rust-analyzer`) - rust-lang#137922 (A few cleanups after the removal of `cfg(not(parallel))`) - rust-lang#137939 (fix order on shl impl) - rust-lang#137946 (Fix docker run-local docs) - rust-lang#137955 (Always allow rustdoc-json tests to contain long lines) - rust-lang#137958 (triagebot.toml: Don't label `test/rustdoc-json` as A-rustdoc-search) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of rust-lang#135767 - tdittr:fn_ptr_calling_conventions-in-deps, r=compiler-errors Future incompatibility warning `unsupported_fn_ptr_calling_conventions`: Also warn in dependencies Tracking issue: rust-lang#130260 As discussed [in the previous PR](https://github.com/rust-lang/rust/pull/128784/files#r1752533758) now the future incompatibility warning is enabled in dependencies. The warning was added in 1.83, while this change will get into stable in 1.86, which gives crate authors three versions to fix the warning. r? compiler-errors

…iaskrgr Rollup of 12 pull requests Successful merges: - rust-lang#135767 (Future incompatibility warning `unsupported_fn_ptr_calling_conventions`: Also warn in dependencies) - rust-lang#137852 (Remove layouting dead code for non-array SIMD types.) - rust-lang#137863 (Fix pretty printing of unsafe binders) - rust-lang#137882 (do not build additional stage on compiler paths) - rust-lang#137894 (Revert "store ScalarPair via memset when one side is undef and the other side can be memset") - rust-lang#137902 (Make `ast::TokenKind` more like `lexer::TokenKind`) - rust-lang#137921 (Subtree update of `rust-analyzer`) - rust-lang#137922 (A few cleanups after the removal of `cfg(not(parallel))`) - rust-lang#137939 (fix order on shl impl) - rust-lang#137946 (Fix docker run-local docs) - rust-lang#137955 (Always allow rustdoc-json tests to contain long lines) - rust-lang#137958 (triagebot.toml: Don't label `test/rustdoc-json` as A-rustdoc-search) r? `@ghost` `@rustbot` modify labels: rollup

This MR contains the following updates: | Package | Update | Change | |---|---|---| | [rust](https://github.com/rust-lang/rust) | minor | `1.86.0` -> `1.87.0` | MR created with the help of [el-capitano/tools/renovate-bot](https://gitlab.com/el-capitano/tools/renovate-bot). **Proposed changes to behavior should be submitted there as MRs.** --- ### Release Notes <details> <summary>rust-lang/rust (rust)</summary> ### [`v1.87.0`](https://github.com/rust-lang/rust/blob/HEAD/RELEASES.md#Version-1870-2025-05-15) [Compare Source](rust-lang/rust@1.86.0...1.87.0) \========================== <a id="1.87.0-Language"></a> ## Language - [Stabilize `asm_goto` feature](rust-lang/rust#133870) - [Allow parsing open beginning ranges (`..EXPR`) after unary operators `!`, `-`, and `*`](rust-lang/rust#134900). - [Don't require method impls for methods with `Self: Sized` bounds in `impl`s for unsized types](rust-lang/rust#135480) - [Stabilize `feature(precise_capturing_in_traits)` allowing `use<...>` bounds on return position `impl Trait` in `trait`s](rust-lang/rust#138128) <a id="1.87.0-Compiler"></a> ## Compiler - [x86: make SSE2 required for i686 targets and use it to pass SIMD types](rust-lang/rust#135408) <a id="1.87.0-Platform-Support"></a> ## Platform Support - [Remove `i586-pc-windows-msvc` target](rust-lang/rust#137957) Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. [platform-support-doc]: https://doc.rust-lang.org/rustc/platform-support.html <a id="1.87.0-Libraries"></a> ## Libraries - [Stabilize the anonymous pipe API](rust-lang/rust#127154) - [Add support for unbounded left/right shift operations](rust-lang/rust#129375) - [Print pointer metadata in `Debug` impl of raw pointers](rust-lang/rust#135080) - [`Vec::with_capacity` guarantees it allocates with the amount requested, even if `Vec::capacity` returns a different number.](rust-lang/rust#135933) - Most `std::arch` intrinsics which don't take pointer arguments can now be called from safe code if the caller has the appropriate target features already enabled (rust-lang/stdarch#1714, rust-lang/stdarch#1716, rust-lang/stdarch#1717) - [Undeprecate `env::home_dir`](rust-lang/rust#137327) - [Denote `ControlFlow` as `#[must_use]`](rust-lang/rust#137449) - [Macros such as `assert_eq!` and `vec!` now support `const {...}` expressions](rust-lang/rust#138162) <a id="1.87.0-Stabilized-APIs"></a> ## Stabilized APIs - [`Vec::extract_if`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.extract_if) - [`vec::ExtractIf`](https://doc.rust-lang.org/stable/std/vec/struct.ExtractIf.html) - [`LinkedList::extract_if`](https://doc.rust-lang.org/stable/std/collections/struct.LinkedList.html#method.extract_if) - [`linked_list::ExtractIf`](https://doc.rust-lang.org/stable/std/collections/linked_list/struct.ExtractIf.html) - [`<[T]>::split_off`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_off) - [`<[T]>::split_off_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_off_mut) - [`<[T]>::split_off_first`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_off_first) - [`<[T]>::split_off_first_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_off_first_mut) - [`<[T]>::split_off_last`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_off_last) - [`<[T]>::split_off_last_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_off_last_mut) - [`String::extend_from_within`](https://doc.rust-lang.org/stable/alloc/string/struct.String.html#method.extend_from_within) - [`os_str::Display`](https://doc.rust-lang.org/stable/std/ffi/os_str/struct.Display.html) - [`OsString::display`](https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.display) - [`OsStr::display`](https://doc.rust-lang.org/stable/std/ffi/struct.OsStr.html#method.display) - [`io::pipe`](https://doc.rust-lang.org/stable/std/io/fn.pipe.html) - [`io::PipeReader`](https://doc.rust-lang.org/stable/std/io/struct.PipeReader.html) - [`io::PipeWriter`](https://doc.rust-lang.org/stable/std/io/struct.PipeWriter.html) - [`impl From<PipeReader> for OwnedHandle`](https://doc.rust-lang.org/stable/std/os/windows/io/struct.OwnedHandle.html#impl-From%3CPipeReader%3E-for-OwnedHandle) - [`impl From<PipeWriter> for OwnedHandle`](https://doc.rust-lang.org/stable/std/os/windows/io/struct.OwnedHandle.html#impl-From%3CPipeWriter%3E-for-OwnedHandle) - [`impl From<PipeReader> for Stdio`](https://doc.rust-lang.org/stable/std/process/struct.Stdio.html) - [`impl From<PipeWriter> for Stdio`](https://doc.rust-lang.org/stable/std/process/struct.Stdio.html#impl-From%3CPipeWriter%3E-for-Stdio) - [`impl From<PipeReader> for OwnedFd`](https://doc.rust-lang.org/stable/std/os/fd/struct.OwnedFd.html#impl-From%3CPipeReader%3E-for-OwnedFd) - [`impl From<PipeWriter> for OwnedFd`](https://doc.rust-lang.org/stable/std/os/fd/struct.OwnedFd.html#impl-From%3CPipeWriter%3E-for-OwnedFd) - [`Box<MaybeUninit<T>>::write`](https://doc.rust-lang.org/stable/std/boxed/struct.Box.html#method.write) - [`impl TryFrom<Vec<u8>> for String`](https://doc.rust-lang.org/stable/std/string/struct.String.html#impl-TryFrom%3CVec%3Cu8%3E%3E-for-String) - [`<*const T>::offset_from_unsigned`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.offset_from_unsigned) - [`<*const T>::byte_offset_from_unsigned`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.byte_offset_from_unsigned) - [`<*mut T>::offset_from_unsigned`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.offset_from_unsigned-1) - [`<*mut T>::byte_offset_from_unsigned`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.byte_offset_from_unsigned-1) - [`NonNull::offset_from_unsigned`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.offset_from_unsigned) - [`NonNull::byte_offset_from_unsigned`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.byte_offset_from_unsigned) - [`<uN>::cast_signed`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.cast_signed) - [`NonZero::<uN>::cast_signed`](https://doc.rust-lang.org/stable/std/num/struct.NonZero.html#method.cast_signed-5). - [`<iN>::cast_unsigned`](https://doc.rust-lang.org/stable/std/primitive.isize.html#method.cast_unsigned). - [`NonZero::<iN>::cast_unsigned`](https://doc.rust-lang.org/stable/std/num/struct.NonZero.html#method.cast_unsigned-5). - [`<uN>::is_multiple_of`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.is_multiple_of) - [`<uN>::unbounded_shl`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.unbounded_shl) - [`<uN>::unbounded_shr`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.unbounded_shr) - [`<iN>::unbounded_shl`](https://doc.rust-lang.org/stable/std/primitive.isize.html#method.unbounded_shl) - [`<iN>::unbounded_shr`](https://doc.rust-lang.org/stable/std/primitive.isize.html#method.unbounded_shr) - [`<iN>::midpoint`](https://doc.rust-lang.org/stable/std/primitive.isize.html#method.midpoint) - [`<str>::from_utf8`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.from_utf8) - [`<str>::from_utf8_mut`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.from_utf8\_mut) - [`<str>::from_utf8_unchecked`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.from_utf8\_unchecked) - [`<str>::from_utf8_unchecked_mut`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.from_utf8\_unchecked_mut) These previously stable APIs are now stable in const contexts: - [`core::str::from_utf8_mut`](https://doc.rust-lang.org/stable/std/str/fn.from_utf8\_mut.html) - [`<[T]>::copy_from_slice`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.copy_from_slice) - [`SocketAddr::set_ip`](https://doc.rust-lang.org/stable/std/net/enum.SocketAddr.html#method.set_ip) - [`SocketAddr::set_port`](https://doc.rust-lang.org/stable/std/net/enum.SocketAddr.html#method.set_port), - [`SocketAddrV4::set_ip`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV4.html#method.set_ip) - [`SocketAddrV4::set_port`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV4.html#method.set_port), - [`SocketAddrV6::set_ip`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV6.html#method.set_ip) - [`SocketAddrV6::set_port`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV6.html#method.set_port) - [`SocketAddrV6::set_flowinfo`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV6.html#method.set_flowinfo) - [`SocketAddrV6::set_scope_id`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV6.html#method.set_scope_id) - [`char::is_digit`](https://doc.rust-lang.org/stable/std/primitive.char.html#method.is_digit) - [`char::is_whitespace`](https://doc.rust-lang.org/stable/std/primitive.char.html#method.is_whitespace) - [`<[[T; N]]>::as_flattened`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_flattened) - [`<[[T; N]]>::as_flattened_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_flattened_mut) - [`String::into_bytes`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.into_bytes) - [`String::as_str`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.as_str) - [`String::capacity`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.capacity) - [`String::as_bytes`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.as_bytes) - [`String::len`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.len) - [`String::is_empty`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.is_empty) - [`String::as_mut_str`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.as_mut_str) - [`String::as_mut_vec`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.as_mut_vec) - [`Vec::as_ptr`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.as_ptr) - [`Vec::as_slice`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.as_slice) - [`Vec::capacity`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.capacity) - [`Vec::len`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.len) - [`Vec::is_empty`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.is_empty) - [`Vec::as_mut_slice`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.as_mut_slice) - [`Vec::as_mut_ptr`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.as_mut_ptr) <a id="1.87.0-Cargo"></a> ## Cargo - [Add terminal integration via ANSI OSC 9;4 sequences](rust-lang/cargo#14615) - [chore: bump openssl to v3](rust-lang/cargo#15232) - [feat(package): add --exclude-lockfile flag](rust-lang/cargo#15234) <a id="1.87.0-Compatibility-Notes"></a> ## Compatibility Notes - [Rust now raises an error for macro invocations inside the `#![crate_name]` attribute](rust-lang/rust#127581) - [Unstable fields are now always considered to be inhabited](rust-lang/rust#133889) - [Macro arguments of unary operators followed by open beginning ranges may now be matched differently](rust-lang/rust#134900) - [Make `Debug` impl of raw pointers print metadata if present](rust-lang/rust#135080) - [Warn against function pointers using unsupported ABI strings in dependencies](rust-lang/rust#135767) - [Associated types on `dyn` types are no longer deduplicated](rust-lang/rust#136458) - [Forbid attributes on `..` inside of struct patterns (`let Struct { #[attribute] .. }) =`](rust-lang/rust#136490) - [Make `ptr_cast_add_auto_to_object` lint into hard error](rust-lang/rust#136764) - Many `std::arch` intrinsics are now safe to call in some contexts, there may now be new `unused_unsafe` warnings in existing codebases. - [Limit `width` and `precision` formatting options to 16 bits on all targets](rust-lang/rust#136932) - [Turn order dependent trait objects future incompat warning into a hard error](rust-lang/rust#136968) - [Denote `ControlFlow` as `#[must_use]`](rust-lang/rust#137449) - [Windows: The standard library no longer links `advapi32`, except on win7.](rust-lang/rust#138233) Code such as C libraries that were relying on this assumption may need to explicitly link advapi32. - [Proc macros can no longer observe expanded `cfg(true)` attributes.](rust-lang/rust#138844) - [Start changing the internal representation of pasted tokens](rust-lang/rust#124141). Certain invalid declarative macros that were previously accepted in obscure circumstances are now correctly rejected by the compiler. Use of a `tt` fragment specifier can often fix these macros. - [Don't allow flattened format_args in const.](rust-lang/rust#139624) <a id="1.87.0-Internal-Changes"></a> ## Internal Changes These changes do not affect any public interfaces of Rust, but they represent significant improvements to the performance or internals of rustc and related tools. - [Update to LLVM 20](rust-lang/rust#135763) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever MR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this MR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this MR, check this box --- This MR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).

Reject `extern "{abi}"` when the target does not support it ## What Promote [`unsupported_fn_ptr_calling_conventions`] from a warning to a hard error, making sure edge-cases will not escape. We now emit hard errors for every case we would return `Invalid` from `AbiMap::canonize_abi` during AST to HIR lowering. In particular, these architecture-specific ABIs now only compile on their architectures[^1]: - amdgpu: "gpu-kernel" - arm: "aapcs", "C-cmse-nonsecure-entry" - avr: "avr-interrupt", "avr-non-blocking-interrupt" - msp430: "msp430-interrupt" - nvptx64: "gpu-kernel", "ptx-kernel" - riscv32 and riscv64: "riscv-interrupt-machine", "riscv-interrupt-supervisor" - x86: "thiscall" - x86 and x86_64: "x86-interrupt" - x86_64: "sysv64", "win64" The panoply of ABIs that are logically x86-specific but actually permitted on all Windows targets remain supported on Windows, as they were before. For non-Windows targets they error if the architecture does not match. Moving the check into AST lowering **is itself a breaking change in rare cases**, above and beyond the cases rustc currently warns about. See "Why or Why Not" for details. ## How We modify rustc_ast_lowering to prevent unsupported ABIs from leaking through the HIR without being checked for target support. Previously ad-hoc checking on various HIR items required making sure we check every HIR item which could contain an `extern "{abi}"` string. This is a losing proposition compared to gating the lowering itself. As a consequence, unsupported ABI strings will now hard-error instead of triggering the FCW `unsupported_fn_ptr_calling_conventions`. However, per #86232 this does cause errors for rare usages of `extern "{abi}"` that were theoretically possible to write in Rust source, without previous warning or error. For instance, trait declarations without impls were never checked. These are the exact kinds of leakages that this new approach prevents. This differs from the following PRs: - #141435 is orthogonal, as it adds a new lint for ABIs we have not warned on and are not touched by this PR - #141877 is subsumed by this, in that this simply cuts out bad functionality instead of adding epicycles for stable code ## Why or Why Not We already made the decision to issue the `unsupported_fn_ptr_calling_conventions` future compatibility warning. It has warned in dependencies since #135767, which reached stable with Rust 1.87. That was released on 2025 May 17, and it is now June. As we already had erred on these ABI strings in most other positions, and warn on stable for function pointer types, this breakage has had reasonable foreshadowing. Upgrading the warning to an error addresses a real problem. In some cases the Rust compiler can attempt to actually compute the ABI for calling a function. We could accept this case and compute unsupported ABIs according to some other ABI, silently[^0]. However, this obviously exposes Rust to errors in codegen. We cannot lower directly to the "obvious" ABI and then trust code generators like LLVM to reliably error on these cases, either. Refactoring the compiler so we could defer more ABI computations would be possible, but seems weakly motivated. Even if we succeeded, we would at minimum risk: - exposing the "whack-a-mole" problem but "approaching linking" instead of "leaving AST" - making it harder to reason about functions we *can* lower further - complicating the compiler for no clear benefit A deprecation cycle for the edge-cases could be implemented first, but it is not very useful for such marginal cases, like this trait declaration without a definition: ```rust pub trait UsedToSneakBy { pub extern "gpu-kernel" fn sneaky(); } ``` Upon any impl, even for provided fn within trait declarations, e.g. `pub extern "gpu-kernel" fn sneaky() {}`, different HIR types were used which would, in fact, get checked. Likewise with anything with function pointers. Thus we would be discussing deprecation cycles for code that is impotent or forewarned[^2]. Implementing a deprecation cycle _is_ possible, but it would likely require emitting multiple of a functionally identical warning or error on code that would not have multiple warnings or errors before. It is also not clear to me we would not find **another**, even more marginal edge-case that slipped through, as "things slip through" is the motivation for checking earlier. Additional effort spent on additional warnings should require committing to a hard limit first. r? lang Fixes #86232 Fixes #132430 Fixes #138738 Fixes #142107 [`unsupported_fn_ptr_calling_conventions`]: #130260 [^1]: Some already will not compile, due to reaching ICEs or LLVM errors. [^0]: We already do this for all `AbiStr` we cannot parse, pretending they are `ExternAbi::Rust`, but we also emit an error to prevent reaching too far into codegen. [^2]: It actually did appear in two cases in rustc's test suite because we are a collection of Rust edge-cases by the simple fact that we don't care if the code actually runs. These cases were excised in c1db989.

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tdittr force-pushed the fn_ptr_calling_conventions-in-deps branch from 739dd7a to 55dc131 Compare January 21, 2025 09:33

rfcbot added proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. disposition-merge This issue / PR is in PFCP or FCP with a disposition to merge it. labels Feb 5, 2025

rfcbot added final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. and removed proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. labels Feb 5, 2025

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tdittr added 4 commits March 3, 2025 08:52

After introducing the warning in 1.83, now also warn in deps

9b78d48

This was left to only warn in the current crate to give users a chance to update their code. Now for 1.86 we also warn users depending on those crates.

Bless UI tests

2bf5cc9

Change variadic-ffi-2 to use a platform independant ABI

310f837

Otherwise this test will include a future incompatibility warning on some targets but not others.

Bless UI tests

6657aa9

tdittr force-pushed the fn_ptr_calling_conventions-in-deps branch from ab4ad6b to 6657aa9 Compare March 3, 2025 08:04

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matthiaskrgr mentioned this pull request Mar 3, 2025

Rollup of 12 pull requests #137959

Merged

bors merged commit 1b4e66e into rust-lang:master Mar 4, 2025
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rustbot added this to the 1.87.0 milestone Mar 4, 2025

BoxyUwU mentioned this pull request Apr 21, 2025

Draft release notes for 1.87 #140133

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workingjubilee mentioned this pull request Jun 6, 2025

Reject extern "{abi}" when the target does not support it #142134

Open

Future incompatibility warning unsupported_fn_ptr_calling_conventions: Also warn in dependencies #135767

Future incompatibility warning unsupported_fn_ptr_calling_conventions: Also warn in dependencies #135767

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Future incompatibility warning `unsupported_fn_ptr_calling_conventions`: Also warn in dependencies #135767

Future incompatibility warning `unsupported_fn_ptr_calling_conventions`: Also warn in dependencies #135767

rfcbot commented Feb 5, 2025 •

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