[Bug c/79586] New: missing -Wdeprecated depending on position of attribute

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79586

            Bug ID: 79586
           Summary: missing -Wdeprecated depending on position of
                    attribute
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: msebor at gcc dot gnu.org
  Target Milestone: ---

GCC (in both C and C++ modes) is inconsistent in warning for uses of entities
declared with attribute deprecated.  In the following program the first four of
all uses of the deprecated variables and types should be diagnosed.  Instead,
only two of them are.  Both Clang and Intel ICC diagnose all four of them as
expected.

$ cat u.C && gcc -O2 -S -Wall -Wextra -Wpedantic -Wunused -xc u.C
int* f0 (void)
{
  int* p __attribute__ ((deprecated)) = 0;

  return p;   // warning, ok
}

int* f1 (void)
{
  int* __attribute__ ((deprecated)) p = 0;

  return p;   // no warning, bug
}

int* f2 (void)
{
  typedef int* P __attribute__ ((deprecated));
  P p = 0;   // warning, ok

  return p;
}

int* f3 (void)
{
  typedef int* __attribute__ ((deprecated)) P;
  P p = 0;   // no warning, bug

  return p;
}
u.C: In function ‘f0’:
u.C:5:3: warning: ‘p’ is deprecated [-Wdeprecated-declarations]
   return p;   // warning, ok
   ^~~~~~
u.C:3:8: note: declared here
   int* p __attribute__ ((deprecated)) = 0;
        ^
u.C: In function ‘f2’:
u.C:18:3: warning: ‘P’ is deprecated [-Wdeprecated-declarations]
   P p = 0;   // warning, ok
   ^