Example: ```coq From Coq Require Import ssreflect ssrfun. From HB Require Import structures. #[primitive] HB.mixin Record AddMonoid_of_TYPE S := { zero : S; add : S -> S -> S; addrA : associative add; add0r : left_id zero add; addr0 : right_id zero add; }. HB.structure Definition AddMonoid := { A of AddMonoid_of_TYPE A }. Check addrA. (* addrA : associative (AddMonoid_of_TYPE.add _ (AddMonoid.class ?s)) where ?s : [ |- AddMonoid.type] *) ``` The type of `addrA` should be `associative add`.