[Bug c++/96310] New: Ignoring Wnonnull via pragma gcc diagnostics still produces a unwanted note

[romain.geissler at amadeus dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96310

            Bug ID: 96310
           Summary: Ignoring Wnonnull via pragma gcc diagnostics still
                    produces a unwanted note
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: romain.geissler at amadeus dot com
  Target Milestone: ---

Hi,

When trying to ignore some uses of null object which apparently are done on
purpose in Boost::concept, I noticed that ignoring the Wnonnull warning via
pragmas still produces an unwanted note giving the details of the callstack.

See this (compiled with -Wnonnull):

struct C {
    void method() {}
};

void f()
{
#pragma GCC diagnostic push                                                     
#pragma GCC diagnostic ignored "-Wnonnull" 
    static_cast<C*>(0)->method();
#pragma GCC diagnostic pop
}

generates the following compiler note output, while we did expect none:

<source>: In function 'void f()':
<source>:2:10: note: in a call to non-static member function 'void C::method()'
    2 |     void method() {}
      |          ^~~~~~
Compiler returned: 0

Cheers,
Romain