compiler/rustc_hir_analysis/README.md

For high-level intro to how type checking works in rustc, see the
[hir typeck] chapter of the [rustc dev guide].

[hir typeck]: https://rustc-dev-guide.rust-lang.org/hir-typeck/summary.html
[rustc dev guide]: https://rustc-dev-guide.rust-lang.org/