HB.mixin anomaly when a parameter with structure is reused as a subject. about hierarchy-builder HOT 2 OPEN

From HB Require Import structures.

HB.mixin Record Interval_of I := {}.
HB.structure Definition Interval := {I of Interval_of I}.
HB.mixin Record Baryspace_of (I : Interval.type) A := {}.
HB.structure Definition Baryspace I := {A of @Baryspace_of I A}.

Fail HB.mixin Record barycentric_interval_of (I : Interval.type) of
  Baryspace_of I I := {}.
(* The error message should be that the head of the subject of
   a structure (here Interval.sort) should probably not be a
   projection from the hierarchy. This will probably cause
   forgetful inheritance problems *)

(* This is the alternative we should strive to suggest, however
   for some reason I failed to diagnose, it fails *)
Fail HB.mixin Record barycentric_interval_of I of
   Interval I & @Baryspace_of I I := {}.

(* This should be also be possible, but fails too *)
Fail HB.structure Definition SelfBaryspace :=
  {I of Interval I & @Baryspace_of I I}.