diff --git a/libstdc++-v3/testsuite/20_util/optional/cons/value_neg.cc b/libstdc++-v3/testsuite/20_util/optional/cons/value_neg.cc
index d3abd03c01a..f6b1886efb9 100644
--- a/libstdc++-v3/testsuite/20_util/optional/cons/value_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/optional/cons/value_neg.cc
@@ -37,3 +37,4 @@ int main()
   }
 }
 // { dg-prune-output "no type .*enable_if" }
+// { dg-prune-output "no matching function for call to 'main..::U::U..'" }
diff --git a/libstdc++-v3/testsuite/20_util/scoped_allocator/69293_neg.cc b/libstdc++-v3/testsuite/20_util/scoped_allocator/69293_neg.cc
index d4be08671f5..a3fbeba79c8 100644
--- a/libstdc++-v3/testsuite/20_util/scoped_allocator/69293_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/scoped_allocator/69293_neg.cc
@@ -42,6 +42,8 @@ static_assert(uses_allocator<X, inner_alloc_type>{}, "");
 static_assert(!is_constructible<X, allocator_arg_t, inner_alloc_type>{}, "");
 static_assert(!is_constructible<X, inner_alloc_type>{}, "");
 
+// { dg-error "too many initializers" "" { target c++20 } 0 }
+
 void
 test01()
 {