If I invoke vim foo/bar/somefile but foo/bar don\'t already exist, Vim refuses to save.
vim foo/bar/somefile
foo/bar
I know I could switch to a shell or do :!mkdi
:!mkdi
I made :saveas! create the directory if missing: https://github.com/henrik/dotfiles/commit/54cc9474b345332cf54cf25b51ddb8a9bd00a0bb
:saveas!