Looks like this also works (might not have worked then, but it works with
current Nim devel):
proc foo(x: int) = echo x
template bar(x) = echo x
bar 10
And similarly (for future readers), this kind of usage also works, for
non-procs:
var a = 200
var b = addr a
b[] = 300
echo a
Though it's not entirely safe.
