https://gcc.gnu.org/g:27d620d67697157f2269f3add4cb830540ac5795
commit r15-6740-g27d620d67697157f2269f3add4cb830540ac5795
Author: Patrick Palka <ppa...@redhat.com>
Date: Thu Jan 9 10:50:16 2025 -0500
c++: tf_partial and instantiate_template [PR117887]
Ever since r15-3530-gdfb63765e994be the extra-args mechanism now expects
to see tf_partial whenever doing a partial substitution containing
dependent arguments. The below testcases show that instantiate_template
for AT with args={T}/{T*} is neglecting to set it in that case, and we
end up ICEing from add_extra_args during the subsequent full substitution.
This patch makes instantiate_template set tf_partial accordingly.
PR c++/117887
gcc/cp/ChangeLog:
* pt.cc (instantiate_template): Set tf_partial if arguments are
dependent.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-requires39.C: New test.
* g++.dg/cpp2a/lambda-targ10.C: New test.
Reviewed-by: Jason Merrill <ja...@redhat.com>
Diff:
---
gcc/cp/pt.cc | 14 +++++++++++---
gcc/testsuite/g++.dg/cpp2a/concepts-requires39.C | 17 +++++++++++++++++
gcc/testsuite/g++.dg/cpp2a/lambda-targ10.C | 17 +++++++++++++++++
3 files changed, 45 insertions(+), 3 deletions(-)
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 081285ef7209..19df9ccb6afd 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -22437,7 +22437,10 @@ instantiate_template (tree tmpl, tree orig_args,
tsubst_flags_t complain)
substitution of a template variable, but the type of the variable
template may be auto, in which case we will call do_auto_deduction
in mark_used (which clears tf_partial) and the auto must be properly
- reduced at that time for the deduction to work. */
+ reduced at that time for the deduction to work.
+
+ Note that later below we set tf_partial iff there are dependent arguments;
+ the above is concerned specifically about the non-dependent case. */
complain &= tf_warning_or_error;
gcc_assert (TREE_CODE (tmpl) == TEMPLATE_DECL);
@@ -22516,9 +22519,14 @@ instantiate_template (tree tmpl, tree orig_args,
tsubst_flags_t complain)
template, not the context of the overload resolution we're doing. */
push_to_top_level ();
/* If there are dependent arguments, e.g. because we're doing partial
- ordering, make sure processing_template_decl stays set. */
+ ordering, make sure processing_template_decl stays set. And set
+ tf_partial mainly for benefit of instantiation of alias templates
+ that contain extra-args trees. */
if (uses_template_parms (targ_ptr))
- ++processing_template_decl;
+ {
+ ++processing_template_decl;
+ complain |= tf_partial;
+ }
if (DECL_CLASS_SCOPE_P (gen_tmpl))
{
tree ctx;
diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-requires39.C
b/gcc/testsuite/g++.dg/cpp2a/concepts-requires39.C
new file mode 100644
index 000000000000..b13682033dac
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-requires39.C
@@ -0,0 +1,17 @@
+// PR c++/117887
+// { dg-do compile { target c++20 } }
+
+template<bool V> struct A { static constexpr bool value = V; };
+
+template<class T>
+using AT = A<requires { requires sizeof(T) != sizeof(T*); }>;
+
+template<class T> struct B { using type = T; };
+
+template<class T>
+void f() {
+ static_assert( B<AT<T>>::type::value);
+ static_assert(!B<AT<T*>>::type::value);
+}
+
+template void f<char>();
diff --git a/gcc/testsuite/g++.dg/cpp2a/lambda-targ10.C
b/gcc/testsuite/g++.dg/cpp2a/lambda-targ10.C
new file mode 100644
index 000000000000..7f175c93062f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/lambda-targ10.C
@@ -0,0 +1,17 @@
+// PR c++/117887
+// { dg-do compile { target c++20 } }
+
+template<bool V, class T> struct A { static constexpr bool value = V; };
+
+template<class T>
+using AT = A<[]{return sizeof(T) != sizeof(T*); }(), T>;
+
+template<class T> struct B { using type = T; };
+
+template<class T>
+void f() {
+ static_assert( B<AT<T>>::type::value);
+ static_assert(!B<AT<T*>>::type::value);
+}
+
+template void f<char>();
