“Modular Implicits”, Leo White, Frédéric Bour, Jeremy Yallop2015-12-07 (Haskell)⁠:

We present modular implicits, an extension to the OCaml language for ad-hoc polymorphism inspired by Scala implicits and modular type classes.

Modular implicits are based on type-directed implicit module parameters, and elaborate straightforwardly into OCaml’s first-class functors.

Basing the design on OCaml’s modules leads to a system that naturally supports many features from other languages with systematic ad-hoc overloading, including inheritance, instance constraints, constructor classes, and associated types.