diff --git a/gcc/c-family/c-ada-spec.cc b/gcc/c-family/c-ada-spec.cc
index b50b38775..b95fae0cc 100644
--- a/gcc/c-family/c-ada-spec.cc
+++ b/gcc/c-family/c-ada-spec.cc
@@ -37,6 +37,7 @@ along with GCC; see the file COPYING3.  If not see
 static int  dump_ada_node (pretty_printer *, tree, tree, int, bool, bool);
 static int  dump_ada_declaration (pretty_printer *, tree, tree, int);
 static void dump_ada_structure (pretty_printer *, tree, tree, bool, int);
+static void dump_nested_types (pretty_printer *, tree, int);
 static char *to_ada_name (const char *, bool *);
 
 #define INDENT(SPACE) \
@@ -1909,2 +1910,3 @@ dump_ada_template (pretty_printer *buffer, tree t, int spc)
       TREE_VISITED (get_underlying_decl (instance)) = 1;
+      dump_nested_types (buffer, TYPE_NAME (instance), spc);
       pp_string (buffer, "type ");
diff --git a/gcc/testsuite/g++.dg/ada-spec/template-nested-types.C b/gcc/testsuite/g++.dg/ada-spec/template-nested-types.C
new file mode 100644
index 000000000..d4ca15a51
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ada-spec/template-nested-types.C
@@ -0,0 +1,37 @@
+/* { dg-do compile } */
+/* { dg-options "-std=gnu++20 -fdump-ada-spec-slim" } */
+/* { dg-final { scan-file template_nested_types_c.ads "package Buffer_int_4 is" } } */
+/* { dg-final { scan-file template_nested_types_c.ads "package Defaults_int_2 is" } } */
+/* { dg-final { scan-file template_nested_types_c.ads "type anon_array[0-9]+ is array \(0 \.\. 3\) of aliased int;" } } */
+/* { dg-final { scan-file template_nested_types_c.ads "type anon_array[0-9]+ is array \(0 \.\. 1\) of aliased int;" } } */
+
+template <typename T, unsigned N>
+struct Buffer
+{
+  T values[N];
+};
+
+template struct Buffer<int, 4>;
+
+template <typename T = int, unsigned N = 2>
+struct Defaults
+{
+  T values[N];
+};
+
+template struct Defaults<>;
+
+extern "C" int
+buffer_sum (const Buffer<int, 4> *value)
+{
+  return value->values[0] + value->values[1]
+    + value->values[2] + value->values[3];
+}
+
+extern "C" int
+defaults_sum (const Defaults<> *value)
+{
+  return value->values[0] + value->values[1];
+}
+
+/* { dg-final { cleanup-ada-spec } } */