Dicebot:
It would be weird exception of general type system rules with no practical justification I can readily imagine.
I partially disagree. It could be useful to have structural typing (http://en.wikipedia.org/wiki/Structural_type_system ) only on tuples (and not on structs), because the formal definition of tuple goes well with structural typing. This also implies the type equivalence of const tuple with a tuple of const fields.
Bye, bearophile
