T'REFLECT should require T is fully constrained
The attribute T'REFLECT
is defined for "any type or subtype T". However that allows one to write string'reflect
where the prefix is unconstrained. What should the result of calling left
, length
, etc. on the resultant array_subtype_mirror
be? It seems like the most sensible behaviour would be to raise an error for this and change the LRM text to something like "any fully-constrained type or subtype T".