passed by reference. It has `Efail` set when an error is found, and
`Eretry` when the type for some element is set via propagation. If
any expression cannot be evaluated immediately, `Enoconst` is set.
passed by reference. It has `Efail` set when an error is found, and
`Eretry` when the type for some element is set via propagation. If
any expression cannot be evaluated immediately, `Enoconst` is set.