Rust proposes cross-crate forward declarations to replace weak symbols

At Kangrejos 2026, Jana Dönszelmann presented a new Rust language feature: a safer, checked analogue of C's weak symbol linking for registering functions that core standard library code calls. She proposed using it to clean up the kernel's handling of integer overflows in Rust.

• Generalizes registration of panic handlers and allocators in std
• Checked analogue of C weak symbols
• Proposed for integer overflow handling in the Rust kernel code