The D programming language has a magic tool called DustMite. It's a so called, source code minimizer. It's inspired by the, seemingly abanded, project Tigris Delta. This whole concept is called delta debugging.
A source code minimizer is used for isolating bugs through successive removal of sub-trees in the ASTs of a set of files, typically placed under a version-controlled project tree.
Does Rust have something similar?
If not, it should definitely invest money in building it. It's a fantastic idea for all languages.
Update: When searching for delta debugging I found this project C-Reduce. It claims to have Rust support!
Note: An important part of the language support is to not reduce assert expressions in unittests 