https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90992
--- Comment #5 from adrien.hamelin at gmail dot com --- The noexcept(false) is just to be extra obvious, we see the same behaviour if we don't mark the function at all. Regards, Adrien Hamelin Le mar. 25 juin 2019 à 14:30, redi at gcc dot gnu.org < gcc-bugzi...@gcc.gnu.org> a écrit : > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90992 > > --- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> --- > This suppresses the second warning if the first is suppressed: > > --- a/gcc/cp/except.c > +++ b/gcc/cp/except.c > @@ -1158,11 +1158,11 @@ maybe_noexcept_warning (tree fn) > { > if (TREE_NOTHROW (fn)) > { > - warning (OPT_Wnoexcept, "noexcept-expression evaluates to %<false%> > " > - "because of a call to %qD", fn); > - warning_at (DECL_SOURCE_LOCATION (fn), OPT_Wnoexcept, > - "but %qD does not throw; perhaps " > - "it should be declared %<noexcept%>", fn); > + if (warning (OPT_Wnoexcept, "noexcept-expression evaluates to > %<false%> > " > + "because of a call to %qD", fn)) > + warning_at (DECL_SOURCE_LOCATION (fn), OPT_Wnoexcept, > + "but %qD does not throw; perhaps " > + "it should be declared %<noexcept%>", fn); > } > } > > > > And this makes the first warning depend on whether the second one is in a > system header: > > --- a/gcc/cp/except.c > +++ b/gcc/cp/except.c > @@ -1158,11 +1158,20 @@ maybe_noexcept_warning (tree fn) > { > if (TREE_NOTHROW (fn)) > { > + location_t loc = DECL_SOURCE_LOCATION (fn); > + > + const bool warn_in_system_headers = > global_dc->dc_warn_system_headers; > + if (in_system_header_at (input_location) && !in_system_header_at > (loc) > + && !warn_in_system_headers) > + global_dc->dc_warn_system_headers = 1; > warning (OPT_Wnoexcept, "noexcept-expression evaluates to %<false%> > " > "because of a call to %qD", fn); > - warning_at (DECL_SOURCE_LOCATION (fn), OPT_Wnoexcept, > + warning_at (loc, OPT_Wnoexcept, > "but %qD does not throw; perhaps " > "it should be declared %<noexcept%>", fn); > + if (in_system_header_at (input_location) && !in_system_header_at > (loc) > + && !warn_in_system_headers) > + global_dc->dc_warn_system_headers = 0; > } > } > > > I don't know which of these is preferable, because I'm not sure if the > point of > the warning is to suggest changing Automatic, or the code in the system > header. > > Tangentially, maybe the warning should not be given when a function is > explicitly marked noexcept(false). That's not the same as an implicit > potentially-throwing exception specification, and presumably the author did > that for a reason. > > -- > You are receiving this mail because: > You reported the bug.
