Top 6 hindley-milner open source projects

Building a modern functional compiler from first principles. (http://dev.stephendiehl.com/fun/)

自作言語処理系のコンパイラ制作

Swift type checking and semantic analysis for developer tools

Interpreter of the ITGL with dynamic type inference

shapechecking neural net DSL using Hindley-Milner type system(compiles to pytorch as proof of concept)

ftor enables ML-like type-directed, functional programming with Javascript including reasonable debugging.