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Re: [PATCH] c++/65579 - set readonly bit on static constexpr members of templates


On 03/17/2016 08:07 AM, Jason Merrill wrote:
On 03/09/2016 05:09 PM, Martin Sebor wrote:
While going through constexpr bugs looking for background
on one I'm currently working on I came across bug 65579 -
[C++11] gcc requires definition of a static constexpr member
even though it is not odr-used.

The bug points out that GCC (sometimes) emits references to
static constexpr data members of class templates even when
they aren't odr-used.  (A more detailed analysis of why this
happens is in my comment #1 on the bug.)

This should have been fixed up in complete_vars; why didn't it work?

IIUC, the job of complete_vars(CLASS) is to complete the type of
variables of class CLASS.  In the test case from the bug (below),
the type of constexpr_member is not CLASS (struct B) but rather
struct A<0>, so its type is never completed there, or apparently
anywhere else.

  template <int> struct A { int i; };
  struct B {
      static constexpr A<0> constexpr_member = { 1 };
  };

Martin


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