c++/modules: Fix stream-in of member using-decls [PR120414]

When streaming in a reference to a data member, we have an oversight
where we did not consider USING_DECLs, despite otherwise handling them
here the same as fields.  This patch corrects that mistake.

	PR c++/120414

gcc/cp/ChangeLog:

	* module.cc (trees_in::tree_node): Allow reading a USING_DECL
	when streaming tt_data_member.

gcc/testsuite/ChangeLog:

	* g++.dg/modules/using-31_a.C: New test.
	* g++.dg/modules/using-31_b.C: New test.

Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
Reviewed-by: Jason Merrill <jason@redhat.com>
(cherry picked from commit 43dddeef7a870ce4db7407f73660504b67a0a919)

diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index f8fa7f14b033e985d1c94e22cb20766d4e488191..e66f725c20d33c3d7b577482d151ef424f517ace 100644 (file)
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -10522,7 +10522,8 @@ trees_in::tree_node (bool is_use)
              res = lookup_field_ident (ctx, u ());
 
            if (!res
-               || TREE_CODE (res) != FIELD_DECL
+               || (TREE_CODE (res) != FIELD_DECL
+                   && TREE_CODE (res) != USING_DECL)
                || DECL_CONTEXT (res) != ctx)
              res = NULL_TREE;
          }

diff --git a/gcc/testsuite/g++.dg/modules/using-31_a.C b/gcc/testsuite/g++.dg/modules/using-31_a.C
new file mode 100644 (file)
index 0000000..75bd872
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/using-31_a.C
@@ -0,0 +1,18 @@
+// PR c++/120414
+// { dg-additional-options "-fmodules" }
+// { dg-module-cmi m }
+
+export module m;
+
+template <int n>
+struct Base {
+  static constexpr int base_static_mbr_n = n;
+};
+
+template <int n>
+struct Derived : Base<n> {
+  using Base<n>::base_static_mbr_n;
+  static constexpr int go(int x = base_static_mbr_n) { return x; }
+};
+
+template struct Derived<1>;

diff --git a/gcc/testsuite/g++.dg/modules/using-31_b.C b/gcc/testsuite/g++.dg/modules/using-31_b.C
new file mode 100644 (file)
index 0000000..e913a77
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/using-31_b.C
@@ -0,0 +1,5 @@
+// PR c++/120414
+// { dg-additional-options "-fmodules" }
+
+module m;
+static_assert(Derived<1>::go() == 1);