On Tue, Sep 29, 2015 at 2:58 PM, Gabriel Scherer <gabriel.scherer@gmail.com>
wrote:

> Note that the polymorphic sets (or maps) are less statically-safe than
> their functorized counterpart, because they are parametrized over their
> comparison function at creation time


The only point in time I've had troubles is when you have a map where its
values and keys range over a type that can recursively contain that map of
the same type. This required a polymorphic compare (from Core) to pull off.


-- 
J.