Rust 1.98.1 fixes incorrect trait-object vtable generation

Rust released version 1.98.1 on September 3 to fix a compiler correctness issue in the preceding release. The announcement says Rust 1.98.0 could, in some circumstances, put a null pointer into a trait-object vtable where a function pointer belonged.

The problem is in emitted code

The Rust team describes the result as undefined behavior, with crashes among the possible outcomes. The announcement does not characterize every program compiled with 1.98.0 as affected.

The immediate engineering task is therefore an artifact inventory. Identify which shipped binaries were built with that compiler version and which build configurations produced them. A workstation’s current compiler version does not establish the provenance of a container image, downloadable executable, or cached release artifact.

Connect the fix to a rebuilt artifact

Updating the toolchain prepares future compilations; a release process should also decide which existing artifacts need rebuilding and replacement. Keep the source revision and dependency inputs fixed where possible, so the corrected compiler is the meaningful difference in the replacement build.

For a suspected regression, preserve the failing input and the old binary while verifying the rebuilt result. That evidence can help distinguish the compiler issue from an unrelated failure that happens to appear during the same rollout.

Release metadata is particularly valuable here. A compiler version recorded alongside an artifact digest gives maintainers a direct way to scope work without reconstructing old CI logs. The point release demonstrates why build provenance is useful for correctness incidents as well as dependency updates: the source can remain unchanged while the generated program needs replacement.