https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72457
--- Comment #6 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
So, perhaps simply:
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index 6bcb41a..83fd9a4 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -734,7 +734,7 @@ cx_check_missing_mem_inits (tree fun, tree body, bool
complain)
|| DECL_ARTIFICIAL (index))
continue;
}
- for (; field != index; field = DECL_CHAIN (field))
+ for (; field != NULL_TREE && field != index; field = DECL_CHAIN (field))
{
tree ftype;
if (TREE_CODE (field) != FIELD_DECL
