May 2025 Monthly report

Overview

Thanks again to Open Source Security, inc and Embecosm for their ongoing support for this project.

Project update

The past month of development was mostly focused on community outreach, with a talk from Pierre-Emmanuel and Arthur at RustWeek in Utrecht, available here. Here, we met with Miguel Ojeda from the Rust-for-Linux project, who informed us that the kernel no longer relies on the alloc standard crate for its function. This makes our job easier, as we are now tasked with compiling core and the kernel’s implementation of alloc, rather than having to catch up with the standard library’s alloc crate.

In practice, this means that gccrs should be useful for Rust-for-Linux in a shorter span of time than originally planned, and we will start integrating the kernel’s source code to our testing infrastructure in our efforts to target those crates. We spent some time last month establishing these milestones, which will be worked on as part of a further 6 months of support from Open Source Security, inc, until the end of Stage 1 for GCC 16.1.

Our next efforts will focus on finishing our name resolution pass for core, and fixing the remaining macro expansion bugs. As part of Google Summer of Code, we will work on improving our pattern matching backend which will allow us to covers all of the patterns used in core. Once that work is complete, we will spend time exploring the Pin semantics and making sure gccrs handles them correctly, as this data structure is used everywhere in the Linux kernel. This will then allow us to start testing the compiler on the kernel crates, hopefully by the end of the summer.

Work also continued on the name resolution rewrite, which is now frustratingly close to replacing our previous implementation. We are resuming work on all areas of the compiler in June. The project received contributions from the usual suspects, with around 25 pull requests from external contributors this month. We are also starting work with our two GSoC students, Zhi Heng and Ryutaro Okada. They will be working on improving our pattern matching backend and on reimplementing certain Rust lints within our front-end rather than by depending on the GCC common compiler framework.

Community call

We will have our next monthly community call on the 9th of June at 9am UTC. You can subscribe to our calendar to see when the next one will be held. The call is open to everyone, even if you would just like to sit-in and listen. You can also subscribe to our mailing-list or join our Zulip chat to be notified of upcoming events.

• Jitsi link
• Calendar ID: 7060a0923ffebd3cb52b1afef35a28ff7b64f05962c9af84c23b1847f1f5f894@group.calendar.google.com
• Google calendar link
• iCal link

Call for contribution

• https://github.com/Rust-GCC/gccrs/issues/2500

• https://github.com/Rust-GCC/gccrs/issues/2376

Completed Activities

• gccrs: Always emit the error highest in the type hierarchy PR3809
• Adjust included headers in `rust-lang.cc` PR3808
• gccrs: Initial support for Return Position Impl Trait PR3807
• gccrs: refactor default infer vars to be its own function PR3806
• gccrs: Remove unneeded clones untill we have an arena allocator for these temps PR3805
• nr2.0: Fix some paths in test files PR3803
• nr2.0: Fix `IfLet` pattern handling PR3802
• nr2.0: Fix test `builtin<sub>abort</sub>.rs` PR3800
• Remove rvalue reference binding PR3795
• Remove unused file PR3794
• gccrs: Fix NR2 ICE in visit_attributes PR3793
• gccrs: We cant clone types as it will dup the node-id PR3792
• Fix `Attr` metavariable binding PR3790
• nr2.0: Fix borrow checking PR3789
• Fix test `same<sub>fieldname</sub>.rs` PR3788
• Adapt attribute lang hook and do some cleanup PR3786
• Small improvements to `DefaultASTVisitor` and nr2.0 PR3784
• Fix ICE segfault on empty static loops PR3781
• gccrs: Prevent passing generic arguments to impl traits in argument position PR3780
• ast: collect InlineAsm node dump PR3779
• gccrs: desugar APIT impl traits PR3778
• gccrs: Emit error diagnostic for bad impl type usage PR3777
• nr2.0: Adjust enum item visitors PR3775
• Improve canonical path handling for impl items PR3774
• Improve struct pattern compilation PR3773
• nr2.0: Adjust resolution of impl items PR3768
• Handle const blocks PR3738

Contributors this month

• Tom Schollenberger (new contributor!)
• Marc Poulhiès
• Owen Avery
• Arthur Cohen
• Pierre-Emmanuel Patry
• Philip Herron
• Gyanendra Banjare

Overall Task Status

Bugs

Test Cases

Milestones Progress

Planned Activities

• Merge fixes in 15.2
• Continue working towards getting more features in 15.2

Risks

We must establish the list of GCC-common changes we need, as we will have to send them upstream before the start of Stage 3 around November. This is the only risk which could incur further problems and prevent more gccrs features from landing in 16.1.