On 1/31/22 11:14, Patrick Palka wrote:
On Mon, Jan 31, 2022 at 11:07 AM Patrick Palka <ppa...@redhat.com> wrote:Here during deduction guide generation for the nested class template B<char(int)>::C, the computation of outer_targs yields the template arguments relative to the primary template for B (i.e. {char(int)}) but what we really what is those relative to the enclosing scope, the partial specialization of B (i.e. {char, int}). Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for trunk? PR c++/104294 gcc/cp/ChangeLog: * pt.cc (ctor_deduction_guides_for): Correct computation of outer_targs. gcc/testsuite/ChangeLog: * g++.dg/cpp1z/class-deduction106.C: New test. --- gcc/cp/pt.cc | 4 +++- .../g++.dg/cpp1z/class-deduction106.C | 19 +++++++++++++++++++ 2 files changed, 22 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/cpp1z/class-deduction106.C diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index f46a7ad6655..0fe0ad4e44e 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -29568,7 +29568,9 @@ ctor_deduction_guides_for (tree tmpl, tsubst_flags_t complain) if (DECL_CLASS_SCOPE_P (tmpl) && CLASSTYPE_TEMPLATE_INSTANTIATION (DECL_CONTEXT (tmpl))) { - outer_args = CLASSTYPE_TI_ARGS (DECL_CONTEXT (tmpl)); + outer_args = copy_node (CLASSTYPE_TI_ARGS (type)); + gcc_assert (TMPL_ARGS_HAVE_MULTIPLE_LEVELS (outer_args));Whoops, this assert should be slightly stronger: TMPL_ARGS_DEPTH (outer_args) > 1. Consider that fixed (pending another bootstrap/regtest cycle).
OK.
+ --TREE_VEC_LENGTH (outer_args); type = TREE_TYPE (most_general_template (tmpl)); } diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction106.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction106.C new file mode 100644 index 00000000000..382f6b70ef5 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction106.C @@ -0,0 +1,19 @@ +// PR c++/104294 +// { dg-do compile { target c++17 } } + +template<class> +struct B; + +template <class R, class... Args> +struct B<R(Args...)> { + template<class T> + struct C { C(T); }; + + C(decltype(nullptr)) -> C<void*>; +}; + +using ty1 = decltype(B<char(int)>::C{0}); +using ty1 = B<char(int)>::C<int>; + +using ty2 = decltype(B<char(int)>::C{nullptr}); +using ty2 = B<char(int)>::C<void*>; -- 2.35.0
