On Mon, May 15, 2017 at 3:58 PM, Martin Sebor <mse...@gmail.com> wrote: >> So how about the following then? I stayed with the catch part and added >> a parameter to the warning to let the user decide on the warnings she/he >> wants to get: -Wcatch-value=n. >> -Wcatch-value=1 only warns for polymorphic classes that are caught by >> value (to avoid slicing), -Wcatch-value=2 warns for all classes that >> are caught by value (to avoid copies). And finally -Wcatch-value=3 >> warns for everything not caught by reference to find typos (like pointer >> instead of reference) and bad coding practices. > > It seems reasonable to me. I'm not too fond of multi-level > warnings since few users take advantage of anything but the > default, but this case is simple and innocuous enough that > I don't think it can do harm.
>> Bootstrapped and regtested on x86_64-pc-linux-gnu. >> OK for trunk? OK. >> If so, would it make sense to add -Wcatch-value=1 to -Wextra or even -Wall? >> I would do this in a seperate patch, becuase I haven't checked what that >> would mean for the testsuite. > > I can't think of a use case for polymorphic slicing that's not > harmful so unless there is a common one that escapes me, I'd say > -Wall. Agreed. But then you'll probably want to allow -Wno-catch-value to turn it off. Jason
