As ZyX said, it looks like you want find.
set wildmenu
set wildmode=longest:full
set path+=.
:find so<Tab>, , so, ( pwd). (<Tab> wildchar.)
:
set wildmode=list:longest
path, .
set path+=~/code
, :
:edit **/so<Tab>
. :help {file} **, . :help starstar-wildcard.