| Message ID | 20230502211310.220156-1-ppalka@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | c++: satisfaction of non-dep member alias template-id | expand |
On 5/2/23 17:13, Patrick Palka wrote: > constraints_satisfied_p already carefully checks dependence of template > arguments before proceeding with satisfaction, so the dependence check > in instantiate_alias_template is unnecessary and overly conservative. > Getting rid of it allows us to check satisfaction ahead of time in more > cases as in the below testcase. > > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for > trunk? OK. > gcc/cp/ChangeLog: > > * pt.cc (instantiate_alias_template): Exit early upon > error from coerce_template_parms. Remove dependence test > guarding constraints_satisfied_p. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp2a/concepts-alias6.C: New test. > --- > gcc/cp/pt.cc | 6 +++--- > gcc/testsuite/g++.dg/cpp2a/concepts-alias6.C | 15 +++++++++++++++ > 2 files changed, 18 insertions(+), 3 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-alias6.C > > diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc > index 3f1cf139bbd..930291917f2 100644 > --- a/gcc/cp/pt.cc > +++ b/gcc/cp/pt.cc > @@ -22178,11 +22178,11 @@ instantiate_alias_template (tree tmpl, tree args, tsubst_flags_t complain) > > args = coerce_template_parms (DECL_TEMPLATE_PARMS (tmpl), > args, tmpl, complain); > + if (args == error_mark_node) > + return args; > > /* FIXME check for satisfaction in check_instantiated_args. */ > - if (flag_concepts > - && !any_dependent_template_arguments_p (args) > - && !constraints_satisfied_p (tmpl, args)) > + if (!constraints_satisfied_p (tmpl, args)) > { > if (complain & tf_error) > { > diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-alias6.C b/gcc/testsuite/g++.dg/cpp2a/concepts-alias6.C > new file mode 100644 > index 00000000000..4acd57d36e6 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-alias6.C > @@ -0,0 +1,15 @@ > +// Verify we can check satisfaction of non-dependent member alias > +// template-ids whose constraints don't depend on outer template > +// arguments ahead of time. > +// { dg-do compile { target c++20 } } > + > +template<class T> > +struct A { > + template<int N> requires (N > 0) > + using at = T; > + > + void f() { > + using ty1 = at<0>; // { dg-error "constraint" } > + using ty2 = at<1>; > + } > +};
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index 3f1cf139bbd..930291917f2 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -22178,11 +22178,11 @@ instantiate_alias_template (tree tmpl, tree args, tsubst_flags_t complain) args = coerce_template_parms (DECL_TEMPLATE_PARMS (tmpl), args, tmpl, complain); + if (args == error_mark_node) + return args; /* FIXME check for satisfaction in check_instantiated_args. */ - if (flag_concepts - && !any_dependent_template_arguments_p (args) - && !constraints_satisfied_p (tmpl, args)) + if (!constraints_satisfied_p (tmpl, args)) { if (complain & tf_error) { diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-alias6.C b/gcc/testsuite/g++.dg/cpp2a/concepts-alias6.C new file mode 100644 index 00000000000..4acd57d36e6 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-alias6.C @@ -0,0 +1,15 @@ +// Verify we can check satisfaction of non-dependent member alias +// template-ids whose constraints don't depend on outer template +// arguments ahead of time. +// { dg-do compile { target c++20 } } + +template<class T> +struct A { + template<int N> requires (N > 0) + using at = T; + + void f() { + using ty1 = at<0>; // { dg-error "constraint" } + using ty2 = at<1>; + } +};