I am working on branch XYZ. I want to know how foo.c in this branch compares with stash{0} on master. Something like
git diff master@stash@{0} foo.c
which does not work. Now I want that stashes foo.c to replace my local file. Something like
git checkout master@stash@{0} foo.c
Edit: I did not realize that stashes aren't owned by a branch, but the stash itself identifies which branch it is a stash of. Problem solved.