| Message ID | 20240215221742.646761-1-polacek@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | c++: wrong looser excep spec for dep noexcept [PR113158] | expand |
On 2/15/24 17:17, Marek Polacek wrote: > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? > > By the ??? below I mean that maybe_instantiate_noexcept could return > a tristate, and then maybe_check_overriding_exception_spec could check > > if (maybe_instantiate_noexcept ().is_unknown ()) > return true; > > and we don't have to add any new checks to maybe_check_o_e_spec. > > -- >8 -- > Here we find ourselves in maybe_check_overriding_exception_spec in > a template context where we can't instantiate a dependent noexcept. > That's OK, but we have to defer the checking otherwise we give wrong > errors. > > PR c++/113158 > > gcc/cp/ChangeLog: > > * search.cc (maybe_check_overriding_exception_spec): Defer checking > when a noexcept couldn't be instantiated. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp0x/noexcept83.C: New test. > --- > gcc/cp/search.cc | 7 +++++ > gcc/testsuite/g++.dg/cpp0x/noexcept83.C | 37 +++++++++++++++++++++++++ > 2 files changed, 44 insertions(+) > create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept83.C > > diff --git a/gcc/cp/search.cc b/gcc/cp/search.cc > index c948839dc53..73d254d6b84 100644 > --- a/gcc/cp/search.cc > +++ b/gcc/cp/search.cc > @@ -1975,6 +1975,13 @@ maybe_check_overriding_exception_spec (tree overrider, tree basefn) > || UNPARSED_NOEXCEPT_SPEC_P (over_throw)) > return true; > > + /* We also have to defer checking when we're in a template and couldn't > + instantiate the noexcept yet. > + ??? maybe_instantiate_noexcept already checked these. Use tristate? */ > + if (type_dependent_expression_p (base_throw) > + || type_dependent_expression_p (over_throw)) I think we also want to avoid comparing value-dependent expressions, but actually checking either one seems like more work than needed here; I'd think we want to defer in a template if the specifiers aren't both exactly true or false. > + return true; > + > if (!comp_except_specs (base_throw, over_throw, ce_derived)) > { > auto_diagnostic_group d; > diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept83.C b/gcc/testsuite/g++.dg/cpp0x/noexcept83.C > new file mode 100644 > index 00000000000..47832bbb44d > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept83.C > @@ -0,0 +1,37 @@ > +// PR c++/113158 > +// { dg-do compile { target c++11 } } > + > +template<typename T> > +struct V { > + static constexpr bool t = false; > +}; > +struct base { > + virtual int f() = 0; > +}; > + > +template<typename T> > +struct derived : base { > + int f() noexcept(V<T>::t) override; > +}; > + > +struct base2 { > + virtual int f() noexcept = 0; > +}; > + > +template<bool B> > +struct W { > + static constexpr bool t = B; > +}; > + > +template<bool B> > +struct derived2 : base2 { > + int f() noexcept(W<B>::t) override; // { dg-error "looser exception specification" } > +}; > + > +void > +g () > +{ > + derived<int> d1; > + derived2<false> d2; // { dg-message "required from here" } > + derived2<true> d3; > +} > > base-commit: b3b3bd250f0a7c22b7d46d3522c8b94c6a35d22a > prerequisite-patch-id: 3beddc8cae6ef7f28cd7eac7240d5f4dad08e5f7
diff --git a/gcc/cp/search.cc b/gcc/cp/search.cc index c948839dc53..73d254d6b84 100644 --- a/gcc/cp/search.cc +++ b/gcc/cp/search.cc @@ -1975,6 +1975,13 @@ maybe_check_overriding_exception_spec (tree overrider, tree basefn) || UNPARSED_NOEXCEPT_SPEC_P (over_throw)) return true; + /* We also have to defer checking when we're in a template and couldn't + instantiate the noexcept yet. + ??? maybe_instantiate_noexcept already checked these. Use tristate? */ + if (type_dependent_expression_p (base_throw) + || type_dependent_expression_p (over_throw)) + return true; + if (!comp_except_specs (base_throw, over_throw, ce_derived)) { auto_diagnostic_group d; diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept83.C b/gcc/testsuite/g++.dg/cpp0x/noexcept83.C new file mode 100644 index 00000000000..47832bbb44d --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept83.C @@ -0,0 +1,37 @@ +// PR c++/113158 +// { dg-do compile { target c++11 } } + +template<typename T> +struct V { + static constexpr bool t = false; +}; +struct base { + virtual int f() = 0; +}; + +template<typename T> +struct derived : base { + int f() noexcept(V<T>::t) override; +}; + +struct base2 { + virtual int f() noexcept = 0; +}; + +template<bool B> +struct W { + static constexpr bool t = B; +}; + +template<bool B> +struct derived2 : base2 { + int f() noexcept(W<B>::t) override; // { dg-error "looser exception specification" } +}; + +void +g () +{ + derived<int> d1; + derived2<false> d2; // { dg-message "required from here" } + derived2<true> d3; +}
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? By the ??? below I mean that maybe_instantiate_noexcept could return a tristate, and then maybe_check_overriding_exception_spec could check if (maybe_instantiate_noexcept ().is_unknown ()) return true; and we don't have to add any new checks to maybe_check_o_e_spec. -- >8 -- Here we find ourselves in maybe_check_overriding_exception_spec in a template context where we can't instantiate a dependent noexcept. That's OK, but we have to defer the checking otherwise we give wrong errors. PR c++/113158 gcc/cp/ChangeLog: * search.cc (maybe_check_overriding_exception_spec): Defer checking when a noexcept couldn't be instantiated. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/noexcept83.C: New test. --- gcc/cp/search.cc | 7 +++++ gcc/testsuite/g++.dg/cpp0x/noexcept83.C | 37 +++++++++++++++++++++++++ 2 files changed, 44 insertions(+) create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept83.C base-commit: b3b3bd250f0a7c22b7d46d3522c8b94c6a35d22a prerequisite-patch-id: 3beddc8cae6ef7f28cd7eac7240d5f4dad08e5f7