This paper proposes a general semantic framework for verifying programs with arbitrary monadic side-effects using Dijkstra monads, which we define as monad-like structures indexed by a specification monad. We prove that any monad morphism between a computational monad and a specification monad gives rise to a Dijkstra monad, which provides great flexibility for obtaining Dijkstra monads tailored to the verification task at hand. We moreover show that a large variety of specification monads can be obtained by applying monad transformers to various base specification monads, including predicate transformers and Hoare-style pre- and postconditions. For defining correct monad transformers, we propose a language inspired by Moggi's monadic metalanguage that is parameterized by a dependent type theory. We also develop a notion of algebraic operations for Dijkstra monads, and start to investigate two ways of also accommodating effect handlers. We implement our framework in both Coq and F*, and illustrate that it supports a wide variety of verification styles for effects such as exceptions, nondeterminism, state, input-output, and general recursion.

@article{paperbot586,
  title = {Dijkstra monads for all},
  author = {Kenji Maillard and Danel Ahman and Robert Atkey and Guido Martínez and Cătălin Hriţcu and Exequiel Rivas and Éric Tanter},
  journal = {Proceedings of the ACM on Programming Languages},
  volume = {3},
  number = {ICFP},
  year = {2019},
  doi = {10.1145/3341708}
}