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Re: How to let C++ compiler raise a warning or error when a const is assigned to a const reference?
On 9/18/06, Miles Bader <miles@gnu.org> wrote:
"Peng Yu" <pengyu.ut@gmail.com> writes:
> I think the compiler should suspect there is something wrong, because
> the buggy code assigns the reference of a temp variable to a const
> reference. It should be that a const reference be assigned to another
> const reference.
It's not "assigning a temp to a const reference" (that's done all the
time, and is perfectly innocent), it's "assigning a reference to a
variable with a certain extent to a reference with a longer-lived
extent." Does gcc have the information easily available to detect that?
Assuming it happens in part of a program we can see, we could detect
that it is stored away in a variable that may live longer than the
original reference.
We could prove that in this case, the store always happens, and thus,
there will always be a dangling reference.
However, unless you made this a flow-sensitive, context-sensitive
interprocedural analysis (which would probably be darn slow given a
large amount of code), it would be very easy to turn that "must"
information into "may" information.