Warnings about shadowed members

[dhaumann]

Issue description

Compiling under Linux, we get many warnings of the following form:

pybind11/detail/common.h(782): warning #1944: declaration of "v" shadows a member of 'this'
the shadowed declaration is at line 764
 any_container(std::vector<T> &&v) : v(std::move(v)) { }

pybind11/detail/common.h(782): warning #3280: declaration hides member "pybind11::detail::any_container<T>::v" (declared at line 764)
 any_container(std::vector<T> &&v) : v(std::move(v)) { }

pybind11/buffer_info.h(28): warning #1944: declaration of "ptr" shadows a member of 'this'
the shadowed declaration is at line 18
 buffer_info(void *ptr, ssize_t itemsize, const std::string &format, ssize_t ndim,

pybind11/buffer_info.h(28): warning #3280: declaration hides member "pybind11::buffer_info::ptr" (declared at line 18)
 buffer_info(void *ptr, ssize_t itemsize, const std::string &format, ssize_t ndim,

pybind11/buffer_info.h(28): warning #1944: declaration of "itemsize" shadows a member of 'this'
 the shadowed declaration is at line 19
 buffer_info(void *ptr, ssize_t itemsize, const std::string &format, ssize_t ndim,

pybind11/buffer_info.h(28): warning #3280: declaration hides member "pybind11::buffer_info::itemsize" (declared at line 19)
 buffer_info(void *ptr, ssize_t itemsize, const std::string &format, ssize_t ndim,

...and many more...

Would it be possible to get this fixed, or what is the best practice here?

[jagerman]

I'm guessing from the warning numbers that this is ICC?

Those warnings, specifically when in a constructor like ctor(a) : a(a) {}; SomeType a;, are pretty useless. There are legitimate cases for avoiding variable masking, but this really isn't one of them. Even MSVC, which is stricter about masking than gcc/clang, doesn't generate them (though I think it would--justifiably so--if a was used in the body rather than merely as member initializers).

Anyway, rant aside, I'd happily merge a PR to disable those warnings within pybind for ICC.

[wojdyr]

GCC and Clang also show such warnings when using -Wshadow (which not many people use, though).