Re: [Boost-users] Boost 1.54.0 Header Warnings: Shadowed Variables

Subject: Re: [Boost-users] Boost 1.54.0 Header Warnings: Shadowed Variables
From: Eric Prud'hommeaux (eric_at_[hidden])
Date: 2013-11-09 05:32:58

* Lars Viklund <zao_at_[hidden]> [2013-11-09 10:23+0100]
> On Fri, Nov 08, 2013 at 06:31:25PM -0600, Tom Browder wrote:
> > I am trying to use Boost 1.54.0 to replace a previous version (1.47)
> > and am using g++ 4.7 with  most warnings turned on.  I am getting many
> > -Wshadow errors and wonder why they exist.  Surely the developers test
> > for such.
> 
> Warning-free code is a pipe dream, particularly if you target an
> open-ended set of compilers and compiler versions.
> 
> Sure, it'd be "nice" if there were no warnings from third party code,
> but it's often detrimental to cover the code in warts that serve no
> actual purpose but to silence warnings, whether it's casting away return
> values, SAL-like annotations, etc.
> 
> > Here is one example from xpressive/detail/utility/hash_peek_bitset.hpp:
> >
> > Both 'icase' and 'count' are reported to shadow members of 'this'.
> >
> > isn't good practice IMHO to do such so that is why I like to use some
> 
> "Good practice" gets you deep into bikeshedding real quick. I'd say it's
> _more_ bug-prone if an author strays too far from his comfort zone in
> projects where it's not required.
> 
> > I could file many bugs but it begs the question of why the warnings
> > are allowed in the first place.
> 
> Different people have different conventions for things like member
> functions. In this case, the author seems to be a fan of the "access any
> members via this" approach, where it's perfectly fine to have shadowing.
> 
> If the whole reason for this hubbub is because you're one of those folks
> that use -Werror, it's your responsibility to tune your set of warnings
> to rule out the ones that cause excessive false positives.
> 
> Warnings are not errors for a reason, they exist as advice that may or
> may not apply.

Or they may, and any convention for managing shadowing applied to
headers would trivially enable a coder to enable shadowing warnings on
their own code. This potentially saves them mysterious bugs and
sniffing around in a debugger before finding that it was something the
compiler could have told them about if it weren't lost in the noise.

I agree with not being religious about it, but -Wshadow is a pretty
achievable goal.

> -- 
> Lars Viklund | zao_at_[hidden]
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