ocaml -rectypes is unsound wrt module subtyping #5343
Original bug ID: 5343
The following example should not be accepted...
module M : sig
let h x = M.g (M.f x);;
val h : int -> bool =
Comment author: @garrigue
Fixed again in trunk, revision 13107.
Abstract types in the current module were assumed to be contractive, which is not true in the case of signatures.