[Issue 3378] [tdpl] ++x should be an lvalue

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http://d.puremagic.com/issues/show_bug.cgi?id=3378



--- Comment #4 from Andrei Alexandrescu <andrei at metalanguage.com> 2009-11-22 17:32:49 PST ---
(In reply to comment #3)
> I guess, why? Why does ++x need to be an lvalue?

1. It's a departure from C. If we do make that departure, we need a good
reason, which I don't know of. (Before you reply with that, I do remember you
mentioned that dmc yields an rvalue and no client every filed a bug.)

2. For most user-defined types returning a value is considerably more expensive
than returning a reference and nontrivial to remove for the compiler when
unused (requires context sensitivity). If built-ins return an rvalue and
user-defined return a reference, generic code will be gratuitously incompatible
across such types.

For me reason #2 is the more important.

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