# Request the presence of a global declaration
fun require_declaration(key: String)
do
var reqs = self.writer.file.required_declarations
if reqs.has(key) then return
reqs.add(key)
var node = current_node
if node != null then compiler.requirers_of_declarations[key] = node
end
src/compiler/abstract_compiler.nit:1861,2--1869,4