Worked on refining the internal array length representation within the rust-lang/rust-clippy repository, focusing on the HIR code path. The project involved removing the deprecated hir::ArrayLen and introducing ConstArgKind::Infer, which streamlined the handling of constant arguments and improved consistency for inferred array lengths in repeat expressions. This targeted refactor, implemented in Rust with a strong emphasis on AST manipulation and compiler development, aimed to reduce maintenance overhead and align rust-clippy’s internals with ongoing changes in the Rust core. The work prioritized correctness and maintainability, consolidating logic to minimize edge-case regressions and enhance the reliability of future lint checks.