The bottlenecks in Rust builds arent't type checking/borrow checking. It's things like macro expansion, module resolution and compilation, codegen from LLVM IR,

The bottlenecks in Rust builds arent't type checking/borrow checking. It's things like macro expansion, module resolution and compilation, codegen from LLVM IR, and linking. Some of these things have workarounds like sccache, using mold instead of the system linker, etc but others are problems that not only remain unsolved but are actively getting worse in the ecosystem.