https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97675
Bug ID: 97675
Summary: GCC does not allow turning off the warning for
exceptions being caught by an earlier handler
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ldionne.2 at gmail dot com
Target Milestone: ---
In the LLVM libc++abi test suite, we test that an exception of type 'Child' is
being caught by an earlier handler of type 'Base'. As a result, GCC (and Clang)
produce a warning saying that the later catch clause (of type 'Child') will
never
be used. This is fine.
However, Clang allows turning off that specific warning using -Wno-exceptions
(or the appropriate warning pragma). GCC doesn't provide that option, which is
problematic because we compile our test suite with -Werror. The options that
are left are:
- To disable these tests with GCC altogether
- To disable -Werror on these tests
Instead, it would be nice if GCC allowed controlling that warning (and perhaps
other related warnings I'm not aware of) using a compiler flag.
Reproducer:
cat <<EOF | g++ -xc++ - -fsyntax-only
struct Base { };
struct Child : Base { };
int main() {
try { throw Child(); }
catch (Base const&) { }
catch (Child const&) { }
}
EOF
Output:
<stdin>: In function 'int main()':
<stdin>:6:5: warning: exception of type 'Child' will be caught
<stdin>:5:5: warning: by earlier handler for 'Base'
Expectation:
Some warning flag (e.g. -Wno-exceptions) allows turning off that warning.
