c++: Propagate using decls from partitions [PR114868]

The modules code currently neglects to set OVL_USING_P on the dependency
created for a using-decl, which causes it not to remember that the
OVL_EXPORT_P flag had been set on it when emitted from the primary
interface unit. This patch ensures that it occurs.

	PR c++/114868

gcc/cp/ChangeLog:

	* module.cc (depset::hash::add_binding_entity): Propagate
	OVL_USING_P for using-declarations.

gcc/testsuite/ChangeLog:

	* g++.dg/modules/using-15_a.C: New test.
	* g++.dg/modules/using-15_b.C: New test.
	* g++.dg/modules/using-15_c.C: New test.

Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>

4 files changed, 34 insertions, 0 deletions

diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index 5b8ff5b..fac0301 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -13150,10 +13150,14 @@ depset::hash::add_binding_entity (tree decl, WMB_Flags flags, void *data_)
 	/* Ignore NTTP objects.  */
 	return false;
 
+      bool unscoped_enum_const_p = false;
       if (!(flags & WMB_Using) && CP_DECL_CONTEXT (decl) != data->ns)
 	{
 	  /* A using that lost its wrapper or an unscoped enum
 	     constant.  */
+	  /* FIXME: Ensure that unscoped enums are differentiated from
+	     'using enum' declarations when PR c++/114683 is fixed.  */
+	  unscoped_enum_const_p = (TREE_CODE (decl) == CONST_DECL);
 	  flags = WMB_Flags (flags | WMB_Using);
 	  if (DECL_MODULE_EXPORT_P (TREE_CODE (decl) == CONST_DECL
 				    ? TYPE_NAME (TREE_TYPE (decl))
@@ -13214,6 +13218,8 @@ depset::hash::add_binding_entity (tree decl, WMB_Flags flags, void *data_)
       if (flags & WMB_Using)
 	{
 	  decl = ovl_make (decl, NULL_TREE);
+	  if (!unscoped_enum_const_p)
+	    OVL_USING_P (decl) = true;
 	  if (flags & WMB_Export)
 	    OVL_EXPORT_P (decl) = true;
 	}
diff --git a/gcc/testsuite/g++.dg/modules/using-15_a.C b/gcc/testsuite/g++.dg/modules/using-15_a.C
new file mode 100644
index 0000000..3f4bb6c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/using-15_a.C
@@ -0,0 +1,14 @@
+// PR c++/114868
+// { dg-additional-options "-fmodules-ts -Wno-global-module" }
+// { dg-module-cmi M:a }
+
+module;
+namespace foo {
+  void a();
+}
+export module M:a;
+
+namespace bar {
+  // propagate usings from partitions
+  export using foo::a;
+}
diff --git a/gcc/testsuite/g++.dg/modules/using-15_b.C b/gcc/testsuite/g++.dg/modules/using-15_b.C
new file mode 100644
index 0000000..4b0cb74
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/using-15_b.C
@@ -0,0 +1,6 @@
+// PR c++/114868
+// { dg-additional-options "-fmodules-ts" }
+// { dg-module-cmi M }
+
+export module M;
+export import :a;
diff --git a/gcc/testsuite/g++.dg/modules/using-15_c.C b/gcc/testsuite/g++.dg/modules/using-15_c.C
new file mode 100644
index 0000000..74dd10a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/using-15_c.C
@@ -0,0 +1,8 @@
+// PR c++/114868
+// { dg-additional-options "-fmodules-ts" }
+import M;
+
+int main() {
+  bar::a();
+  foo::a();  // { dg-error "not been declared" }
+}