Fixed by r12-7264.
PR c++/103443
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/consteval29.C: New test.
---
gcc/testsuite/g++.dg/cpp2a/consteval29.C | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/consteval29.C
diff --git a/gcc/testsuite/g++.dg/cpp2a/consteval29.C
b/gcc/testsuite/g++.dg/cpp2a/consteval29.C
new file mode 100644
index 00000000000..61590225bd6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/consteval29.C
@@ -0,0 +1,20 @@
+// PR c++/103443
+// { dg-do compile { target c++20 } }
+
+template<int...>
+struct A { };
+
+template<int... Is>
+consteval unsigned index_sequence2mask(A<Is...>) {
+ if constexpr (sizeof...(Is) == 0u)
+ return 0u;
+ else
+ return ((1u << Is) | ...);
+}
+
+template<unsigned Mask = index_sequence2mask(A<1,2,3>{})>
+void use_mask();
+
+int main() {
+ use_mask();
+}
--
2.35.1.354.g715d08a9e5
