fact: Definition crunret (A B : UU0) (m : M A) (s : B) : crun m -> crun (m >> Ret s) = Some s.
imports: JMeq mathcomp(all_ssreflect) mathcomp(finmap) mathcomp(classical_sets) monae_lib HB(structures) hierarchy monad_lib fail_lib state_lib trace_lib monad_transformer