func /*test:def*/<base>`foo`</base>(<arglabel index=0>`x`</arglabel><param index=0></param>: Int) {}
/*test:call*/<base>`foo`</base>(<callarg index=0>`x`</callarg><callcolon index=0>: </callcolon>2)
_ = /*test:ref*/<base>`foo`</base>(<sel index=0>`x`</sel>:)