From: Jason Merrill <jason@redhat.com>
Date: Mon, 3 Nov 2025 14:51:38 +0000 (+0300)
Subject: c++: modules and deprecated namespaces
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ca554581288fc27559df8150c1a5a915b915bc2b;p=thirdparty%2Fgcc.git

c++: modules and deprecated namespaces

20_util/rel_ops.cc was failing because the gcm didn't represent
[[deprecated]] on a namespace.  Are there any other attributes we're
missing?

gcc/cp/ChangeLog:

	* module.cc (module_state::write_namespaces): Handle
	TREE_DEPRECATED.
	(module_state::read_namespaces): Likewise.

gcc/testsuite/ChangeLog:

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

diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index e0b9efa02b6..b475b07dcb1 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -17246,13 +17246,16 @@ module_state::write_namespaces (elf_out *to, vec<depset *> spaces,
 	flags |= 4;
       if (DECL_MODULE_EXPORT_P (ns))
 	flags |= 8;
+      if (TREE_DEPRECATED (ns))
+	flags |= 16;
 
       dump () && dump ("Writing namespace:%u %N%s%s%s%s",
 		       b->cluster, ns,
 		       flags & 1 ? ", public" : "",
 		       flags & 2 ? ", inline" : "",
 		       flags & 4 ? ", purview" : "",
-		       flags & 8 ? ", export" : "");
+		       flags & 8 ? ", export" : "",
+		       flags & 16 ? ", deprecated" : "");
       sec.u (b->cluster);
       sec.u (to->name (DECL_NAME (ns)));
       write_namespace (sec, b->deps[0]);
@@ -17328,7 +17331,8 @@ module_state::read_namespaces (unsigned num)
 		       flags & 1 ? ", public" : "",
 		       flags & 2 ? ", inline" : "",
 		       flags & 4 ? ", purview" : "",
-		       flags & 8 ? ", export" : "");
+		       flags & 8 ? ", export" : "",
+		       flags & 16 ? ", deprecated" : "");
       bool visible_p = ((flags & 8)
 			|| ((flags & 1)
 			    && (flags & 4)
@@ -17349,6 +17353,9 @@ module_state::read_namespaces (unsigned num)
 	    DECL_MODULE_EXPORT_P (inner) = true;
 	}
 
+      if (flags & 16)
+	TREE_DEPRECATED (inner) = true;
+
       if (tags)
 	DECL_ATTRIBUTES (inner)
 	  = tree_cons (get_identifier ("abi_tag"), tags, DECL_ATTRIBUTES (inner));
diff --git a/gcc/testsuite/g++.dg/modules/namespace-15_a.C b/gcc/testsuite/g++.dg/modules/namespace-15_a.C
new file mode 100644
index 00000000000..7c0c0e684e2
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/namespace-15_a.C
@@ -0,0 +1,9 @@
+// Test that namespace deprecation is represented in the gcm.
+
+// { dg-additional-options "-fmodules" }
+
+export module M;
+
+export {
+  namespace [[deprecated]] N { }
+}
diff --git a/gcc/testsuite/g++.dg/modules/namespace-15_b.C b/gcc/testsuite/g++.dg/modules/namespace-15_b.C
new file mode 100644
index 00000000000..5128e826602
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/namespace-15_b.C
@@ -0,0 +1,5 @@
+// { dg-additional-options -fmodules }
+
+import M;
+
+using namespace N;		// { dg-warning "deprecated" }