On Sat, 22 Oct 2022 at 00:28, Marek Polacek wrote: > I've run the testsuite/bootstrap with the warning enabled by default. > There were just a few FAILs: > * g++.dg/warn/Wdangling-pointer-2.C > * 20_util/any/misc/any_cast.cc > * 20_util/forward/c_neg.cc > * 20_util/forward/f_neg.cc
These two are XFAIL tests, they're checking for a required static assert due to misusing std::forward, so I don't think we want to change them to remove a "bug" (they're meant to be buggy). I think they should use -Wno-dangling-reference > * experimental/any/misc/any_cast.cc > all of these look like genuine bugs. A bootstrap with the warning > enabled by default passed. I've attached a patch for the two any_cast.cc tests that avoids creating dangling references, without changing the intended behaviour of the tests.
diff --git a/libstdc++-v3/testsuite/20_util/any/misc/any_cast.cc b/libstdc++-v3/testsuite/20_util/any/misc/any_cast.cc index 8d63dfbba9b..43f90c336c9 100644 --- a/libstdc++-v3/testsuite/20_util/any/misc/any_cast.cc +++ b/libstdc++-v3/testsuite/20_util/any/misc/any_cast.cc @@ -93,7 +93,8 @@ void test03() MoveEnabled m; MoveEnabled m2 = any_cast<MoveEnabled>(any(m)); VERIFY(move_count == 1); - MoveEnabled&& m3 = any_cast<MoveEnabled&&>(any(m)); + auto rvalue = [](MoveEnabled&&) { }; + rvalue(any_cast<MoveEnabled&&>(any(m))); // No move construction, just a cast. VERIFY(move_count == 1); } diff --git a/libstdc++-v3/testsuite/experimental/any/misc/any_cast.cc b/libstdc++-v3/testsuite/experimental/any/misc/any_cast.cc index f3ce83ad702..98347f6d37d 100644 --- a/libstdc++-v3/testsuite/experimental/any/misc/any_cast.cc +++ b/libstdc++-v3/testsuite/experimental/any/misc/any_cast.cc @@ -92,7 +92,8 @@ void test03() MoveEnabled m; MoveEnabled m2 = any_cast<MoveEnabled>(any(m)); VERIFY(move_count == 1); - MoveEnabled&& m3 = any_cast<MoveEnabled&&>(any(m)); + auto rvalue = [](MoveEnabled&&) { }; // Can only be called with an rvalue. + rvalue(any_cast<MoveEnabled&&>(any(m))); // Doesn't move, just casts to rval. VERIFY(move_count == 1); struct MoveDeleted { @@ -101,8 +102,9 @@ void test03() MoveDeleted(const MoveDeleted&) = default; }; MoveDeleted md; - MoveDeleted&& md2 = any_cast<MoveDeleted>(any(std::move(md))); - MoveDeleted&& md3 = any_cast<MoveDeleted&&>(any(std::move(md))); + auto rvalue2 = [](MoveDeleted&&) { }; // Can only be called with an rvalue. + rvalue2(any_cast<MoveDeleted>(any(std::move(md)))); + rvalue2(any_cast<MoveDeleted&&>(any(std::move(md)))); } void test05()