-We have to set the #:allocation to either @verb{~#:each-subclass~} or
-@verb{~#:class~}.@footnote{#:class should be fine, except there is @uref{https://debbugs.gnu.org/cgi/bugreport.cgi?bug=25211,a bug in Guile} which keeps
-us from using it for now.}
+We have to set the #:allocation to either @verb{~#:each-subclass~}
+and use @verb{~#:init-thunk~}.@footnote{@verb{~build-subclass~} returns
+a thunk to be called later so that each subclass may correctly build
+its own instance. This is important because the structure returned
+contains a cache, which may vary from subclass to subclass based on
+its inheritance structure.}