If you've got:

use expiration

import "./foo.zed"

definition resource {}

in one file and then this in foo.zed:

use expiration

definition user {}

The compiler will yell at you about multiple use expiration directives. The "normal" behavior for use directives in other languages is that they apply to the file, not to the entire bundled whole, but that's not the way our system behaves.

The simplest way to do this is likely to allow for duplicates and then merge them.