For subexpressions q and tag and pack args,
let TRY-QUERY(q, tag, args...) be expression-equivalent to
AS-CONST(q).query(tag, args...)
if that expression is well-formed, and
AS-CONST(q).query(tag) otherwise
except that args... is evaluated.
For subexpressions q and tag and pack args,
let HIDE-SCHED(q) be an object o such that
o.query(tag, args...) is ill-formed when the decayed type of tag is
get_scheduler_t or get_domain_t, and
q.query(tag, args...) otherwise.