[Coding Guidelines] Meeting notes for 2025-07-16 (#373)

* [Coding Guidelines] Add agenda for 2025-07-16

* [Coding Guidelines] Post-meeting notes for 2025-07-16

Author: AlexCeleste

subcommittee/coding-guidelines/meetings/2025-07-16/minutes.md

@@ -0,0 +1,107 @@
+# **Coding Guidelines Subcommittee Meeting on 2025-07-16 @ 1600 BST / 1700 CEST / 1100 EDT / 2025-07-17 @ 0000 JST**
+
+[Conversion](https://www.worldtimebuddy.com/?qm=1&lid=14,12,5,1850147&h=14&date=2025-7-16&sln=16-17&hf=1) between common time zones of attendees.
+
+| Search Key | Description |
+| ----- | ----- |
+| \[todo\] | Action Item |
+| \[decision\] | Something decided on |
+| \[important\] | Key information |
+
+## **Agenda**
+
+1. Solicitation of notetaker  
+2. Acceptance of [Previous Meeting Minutes](https://github.com/rustfoundation/safety-critical-rust-consortium/blob/main/subcommittee/coding-guidelines/meetings/2025-07-02/minutes.md)  
+3. Introduction of any new members  
+4. Review of [revised and rescoped milestone](https://github.com/rustfoundation/safety-critical-rust-coding-guidelines/milestone/1) focused on shaking out initial issues with coding guidelines process and philosophy \- 5 mins  
+5. Discussion \- 15 mins  
+   * Discuss provenance and the `std::ptr` API (Felix, David)  
+6. Working session \- 20 mins  
+   * Read through [CERT C rules](https://wiki.sei.cmu.edu/confluence/display/c/2+Rules) together a bit  
+   * Identify sections and folks that would like to translate these into the Rust coding guidelines  
+     * [Rule 04\. Integers (INT)](https://wiki.sei.cmu.edu/confluence/pages/viewpage.action?pageId=87152052)  
+     * [Rule 05\. Floating Point (FLP)](https://wiki.sei.cmu.edu/confluence/pages/viewpage.action?pageId=87152181)  
+     * [Rule 03\. Expressions (EXP)](https://wiki.sei.cmu.edu/confluence/pages/viewpage.action?pageId=87152200)  
+7. Review session \- 10 mins  
+   * Review open [PRs](https://github.com/rustfoundation/safety-critical-rust-coding-guidelines/pulls) & [issues](https://github.com/rustfoundation/safety-critical-rust-coding-guidelines/issues)  
+8. Round table \- 5 mins
+
+## **Check-in area**
+
+**Please add your name, and an emoji that describes your day.**
+
+* Alex Celeste ☕  
+* David Svoboda :)  
+* Enow Scott 🙂  
+* Andrew Fernandes ☕🥱  
+* [Robert C. Seacord](mailto:robert.seacord@woven-planet.global) 😣  
+* Douglas Deslauriers 🏙️  
+* Oreste Bernardi🫤  
+* Tiago Manczak ☺️  
+* Achim Kriso 🦆  
+* El Araby El Mahdi 🌋👍  
+* Christof Petig 🌧️
+
+**Notetaker:**
+
+* David Svoboda
+
+## **Housekeeping section**
+
+* Document space: [coding-guidelines](https://github.com/rustfoundation/safety-critical-rust-consortium/tree/main/subcommittee/coding-guidelines)  
+* Zulip: [safety-critical-consortium: Coding Guidelines](https://rust-lang.zulipchat.com/#narrow/channel/445688-safety-critical-consortium/topic/Coding.20Guidelines)  
+* [Early Alpha Milestone](https://github.com/rustfoundation/safety-critical-rust-coding-guidelines/milestone/1)
+
+## **Tasks**
+
+* Search for the \[todo\] markers
+
+## **Meeting Minutes**
+
+* Solicitation of notetaker  
+* Acceptance of [Previous Meeting Minutes](https://github.com/rustfoundation/safety-critical-rust-consortium/blob/main/subcommittee/coding-guidelines/meetings/2025-07-02/minutes.md)  
+* Introduction of any new members  
+* Review of [revised and rescoped milestone](https://github.com/rustfoundation/safety-critical-rust-coding-guidelines/milestone/1) focused on shaking out initial issues with coding guidelines process and philosophy \- 5 mins  
+* Discussion \- 15 mins  
+  * Discuss provenance and the `std::ptr` API (Felix, David), based on an informal discussion in the sync meeting yesterday after investigating INT36-C  
+  * Two forms of provenance, strict and exposed, investigated based on the last three clauses of INT36 \- the new API should make it unnecessary to go through bare integer representations in order to apply things like masks with the strict provenance option; there is also the exposed option for when this is absolutely necessary i.e. for hardcoded hardware addresses  
+  * Rust has the same concepts of alignment as C does; same concepts of “pointing to an entity” as C does; trap representations are more specific to C  
+  * Leads to a question: does this group care about \`unsafe\` as well as safe code? Should there be a distinction in the rules? Are we currently creating guidelines applicable to \`unsafe\`? Current consensus is that the group has not yet made this distinction  
+  * The second paragraph raises some interesting questions about the permissiveness of the \`as\` operator and what can be converted to/from a pointer; exposes older assumptions that \`usize\` will always be the right size for pointers; want a Clippy lint for conversions between \_any\_ pointer and integer pairings \- \`usize\` is no longer guaranteed to be sufficient for this  
+  * Third paragraph is less concerning for guidelines  
+  * A lot of the knowledge about this is centralized into individuals \- an issue for many aspects of the language and its operational semantics  
+  * Three tiers of support, documented in https://doc.rust-lang.org/rustc/platform-support.html  
+  * tier 1 \= Intel & ARM (no embedded systems)  
+  * Indicates a model of support for platforms; does not indicate what Rust aims to support.  
+  * Do we want a rule "use only tier 1 platforms"?  
+  * This would rule out lots of embedded platforms.  
+* Working session \- 20 mins  
+  * Read through [CERT C rules](https://wiki.sei.cmu.edu/confluence/display/c/2+Rules) together a bit  
+  * Identify sections and folks that would like to translate these into the Rust coding guidelines  
+    * [Rule 04\. Integers (INT)](https://wiki.sei.cmu.edu/confluence/pages/viewpage.action?pageId=87152052)  
+    * [Rule 05\. Floating Point (FLP)](https://wiki.sei.cmu.edu/confluence/pages/viewpage.action?pageId=87152181)  
+    * [Rule 03\. Expressions (EXP)](https://wiki.sei.cmu.edu/confluence/pages/viewpage.action?pageId=87152200)  
+* Review session \- 10 mins  
+  * Review open [PRs](https://github.com/rustfoundation/safety-critical-rust-coding-guidelines/pulls) & [issues](https://github.com/rustfoundation/safety-critical-rust-coding-guidelines/issues)  
+    * [https://github.com/rustfoundation/safety-critical-rust-coding-guidelines/pull/132](https://github.com/rustfoundation/safety-critical-rust-coding-guidelines/pull/132) (do not divide by zero)  
+      * The spec does not indicate what x / 0 actually does, but it seems to panic on some platforms.  
+      * Been reviewed by Felix, please look offline & provide feedback.  
+    * Request for action item to create issue about unsafe vs. safe tag on guidelines.  
+* Round table \- 5 mins  
+  * Seacord: For https://github.com/rustfoundation/safety-critical-rust-coding-guidelines/issues/137  
+  * (Use matching types at the language boundary)  
+    * Seacord: Interface using\_matching\_types at language boundaries. How concerned are we about portability? At CERT we limit "safe" labels to working on a particular platform. An interface that uses C short or char would never be portable?  
+    * Alex: This might warrant a guideline  
+    * Svoboda: yes. There is no C interface. Instead there is one interface to x86-64-Linux-GCC C, one to x86-32-Linux-Clang, and so on. Each has implementation-defined integer sizes, and most functions rely on them.  
+    * Seacord: We could use several more code examples: one with static assertions, one with fixed-width C types.  
+    * Alex: This is a rich area for mistakes.  
+  * Douglas: FLS Speclock file is out of date.  I will update.
+
+## **Material**
+
+Any material to read before the meeting should be included here.
+
+### **GitHub Project Board for Work Items**
+
+* [Work Item Board](https://github.com/orgs/rustfoundation/projects/1)
+