[Bug c++/66472] -Wshadow gets confused by using statements in template classes

["manu at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66472

Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |manu at gcc dot gnu.org

--- Comment #4 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
> As suggested there https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57709#c16, I
> tried to break at the call to warning_at to give you more input, but with no
> luck, as if warning_at was not called at all. (I also tried to break at any
> *warning* symbol with same result).

Probably because you are debugging the driver instead of the compiler proper:
https://gcc.gnu.org/wiki/DebuggingGCC

Sorry, I should have mentioned that.
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To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/66472] -Wshadow gets confused by using statements in template classes
Date: Tue, 09 Jun 2015 13:15:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66472

--- Comment #5 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
(In reply to Marc Glisse from comment #3)
> I compile with g++ -wrapper gdb,--args ... where this gcc was compile with
> -O0 -g. Breaking on warning_at shows that member is a using_decl.

Is there anyway to tell what the using_decl is actually representing? Perhaps
via its type?

I think this is one of those cases where false negatives are more annoying than
false positives are dangerous, thus maybe the warning should be silent for all
using_decl.
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Subject: [Bug c++/66472] -Wshadow gets confused by using statements in template classes
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idf472

--- Comment #6 from Christoph Hertzberg <chtz at informatik dot uni-bremen.de> ---
Ok, good point on shadowing free functions.
Next pathological example: If you have a template specialization of your Base
with a static member variable called `size`, wouldn't the warning make sense?

template <class T>
struct Base {
  Base(int y) {std::cout << "y=" <<y <<"\n";}
  T size();
};

template<class T>
struct Bar : Base<T> {
  using Base<T>::size;
  Bar(int size) : Base<T>(size) {}
  Bar() : Base<T>(size) {} // only works for T==int
};

// Specialization, probably not visible when Bar is defined:
template<>
struct Base<int> {
  Base<int>(int x) {std::cout << "x=" <<x <<"\n";}
  const static int sizeB;
};