On Fri, 16 Feb 2024, Marek Polacek wrote: > On Fri, Feb 16, 2024 at 03:58:02PM -0500, Jason Merrill wrote: > > 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. > > Yeah, that'll work too. So like this? > > Bootstrap/regtest running; dg.exp passed. FWIW, the new check only > triggered on the new test. > > Thanks, > > -- >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 & evaluated to false/true. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp0x/noexcept83.C: New test. > --- > gcc/cp/search.cc | 11 ++++++++ > gcc/testsuite/g++.dg/cpp0x/noexcept83.C | 37 +++++++++++++++++++++++++ > 2 files changed, 48 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..554ba71f4a7 100644 > --- a/gcc/cp/search.cc > +++ b/gcc/cp/search.cc > @@ -1975,6 +1975,17 @@ 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 & evaluate the noexcept to true/false. */ > + if (processing_template_decl) > + if ((base_throw > + && (base_throw != noexcept_true_spec > + || base_throw != noexcept_false_spec))
Shouldn't these innermost || be &&? > + || (over_throw > + && (over_throw != noexcept_true_spec > + || over_throw != noexcept_false_spec))) > + 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: 40b8d7b73ad2ce498758c1d9bd38ebdbc26b918b > -- > 2.43.2 > >