Workaround to avoid `injection` from unfolding equalities on `dom`
As reported by @vsiles and @msammler on Mattermost the tactics simplify_eq
and injection
accidentally unfold equalities dom (gset A) m1 = dom (gset A) m2
into merge ...
.
The culprit is that the definition of dom
on gmap
starts with a constructor MapSet
. This MR tweaks the definition a bit, by inserting an eta expansion, to avoid that.
Edited by Robbert Krebbers