[gcc r16-3558] c++/modules: Mark implicit inline namespaces as purview [PR121724]

[Nathaniel Shead via Gcc-cvs]

https://gcc.gnu.org/g:03505e5b93e635907ed5ef7edac11da4026655e2

commit r16-3558-g03505e5b93e635907ed5ef7edac11da4026655e2
Author: Nathaniel Shead <nathanielosh...@gmail.com>
Date:   Mon Sep 1 21:28:03 2025 +1000

    c++/modules: Mark implicit inline namespaces as purview [PR121724]
    
    When we push an existing namespace within the module purview for the
    first time, we also need to mark any parent inline namespaces as purview
    to not confuse the streaming logic.
    
            PR c++/121724
    
    gcc/cp/ChangeLog:
    
            * name-lookup.cc (push_namespace): Mark inline namespace
            contexts as purview if needed.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/modules/namespace-12_a.C: New test.
            * g++.dg/modules/namespace-12_b.C: New test.
    
    Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com>

Diff:
---
 gcc/cp/name-lookup.cc                         |  3 +++
 gcc/testsuite/g++.dg/modules/namespace-12_a.C | 17 +++++++++++++++++
 gcc/testsuite/g++.dg/modules/namespace-12_b.C |  6 ++++++
 3 files changed, 26 insertions(+)

diff --git a/gcc/cp/name-lookup.cc b/gcc/cp/name-lookup.cc
index ba6246776258..f5e80503678e 100644
--- a/gcc/cp/name-lookup.cc
+++ b/gcc/cp/name-lookup.cc
@@ -9273,6 +9273,9 @@ push_namespace (tree name, bool make_inline)
                  gcc_checking_assert (!(tree)slot || (tree)slot == ctx);
                  slot = ctx;
                }
+
+             if (module_purview_p ())
+               DECL_MODULE_PURVIEW_P (ctx) = true;
            }
        }
 
diff --git a/gcc/testsuite/g++.dg/modules/namespace-12_a.C 
b/gcc/testsuite/g++.dg/modules/namespace-12_a.C
new file mode 100644
index 000000000000..a43262638f12
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/namespace-12_a.C
@@ -0,0 +1,17 @@
+// PR c++/121724
+// { dg-additional-options "-fmodules -Wno-global-module" }
+// { dg-module-cmi foo }
+
+module;
+namespace A {
+  inline namespace X {
+    namespace B {
+    }
+  }
+}
+export module foo;
+export namespace A {
+  namespace B {
+    struct S {};
+  }
+}
diff --git a/gcc/testsuite/g++.dg/modules/namespace-12_b.C 
b/gcc/testsuite/g++.dg/modules/namespace-12_b.C
new file mode 100644
index 000000000000..8c429ba9e73b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/namespace-12_b.C
@@ -0,0 +1,6 @@
+// PR c++/121724
+// { dg-additional-options "-fmodules" }
+
+import foo;
+using T = A::B::S;
+using T = A::X::B::S;