https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57632
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |diagnostic
Resolution|INVALID |---
Ever confirmed|0 |1
Last reconfirmed| |2022-01-07
Status|RESOLVED |NEW
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I agree with comment 3 that the current diagnostic is poor:
#include <new>
void* operator new(std::size_t mem) throw(std::bad_alloc);
void* operator new(std::size_t mem) throw(std::bad_alloc);
g++ -std=c++11 -c new.cc -Wno-deprecated
new.cc:3:7: error: declaration of ‘void* operator new(std::size_t) throw
(std::bad_alloc)’ has a different exception specifier
3 | void* operator new(std::size_t mem) throw(std::bad_alloc);
| ^~~~~~~~
new.cc:2:7: note: from previous declaration ‘void* operator new(std::size_t)’
2 | void* operator new(std::size_t mem) throw(std::bad_alloc);
| ^~~~~~~~
Why does it accept the incorrect exception specification on line 2, but then
give an error for an identical one on line 3? Why do we refer to line 2 in the
note and say it's different, when it's not?
Paolo's explanation in comment 1 doesn't make the behaviour correct, it just
explains why we behave like that. Either both redeclarations should be valid or
neither should be valid.
So I think either we should either:
- accept both redeclarations (as Clang does), or
- give a diagnostic (maybe a pedwarn) for the first redeclaration because it
doesn't match the one in <new> (and the implicit one predefined by the
compiler), and fix the diagnostic to refer to the previous declaration in <new>
instead of the one on line 2.
