[Issue 9872] format should include class field values

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=9872

--- Comment #5 from Andrej Mitrovic <andrej.mitrovich at gmail.com> ---
I think the really consistent part about formatting in Phobos is that the
output tends to be semantically-correct syntax.

S(0, 0) is correct as you can construct an instance of `S` this way. But `C(0,
0)` would be semantically incorrect as that's not how classes are constructed.
You'd (likely) need to use `new C` and you'd have to care about which
constructors are actually implemented, so `new C(0, 0)` might not even be
semantically correct either.

Perhaps instead of changing default formatting a better option would be to have
a format spec that dumps out the entire representation of the aggregate. "%s"
is taken but we could introduce something else.

We could also just close this as WONTFIX.

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