1 files changed, 81 insertions, 0 deletions
diff --git a/compilerplugins/clang/nestedunnamed.cxx b/compilerplugins/clang/nestedunnamed.cxx
new file mode 100644
index 000000000..adc4f81a8
--- /dev/null
+++ b/compilerplugins/clang/nestedunnamed.cxx
@@ -0,0 +1,81 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+#ifndef LO_CLANG_SHARED_PLUGINS
+
+#include <cassert>
+
+#include "plugin.hxx"
+
+// Warn about unnamed namespaces nested (directly) within unnamed namespaces.  (It can be hard to
+// keep track whether a certain spot in a source file is already in an unnamed namespace, so it
+// happens that additions to the source add redundant, nested unnamed namespaces.)
+
+namespace
+{
+class NestedUnnamed : public loplugin::FilteringPlugin<NestedUnnamed>
+{
+public:
+    explicit NestedUnnamed(loplugin::InstantiationData const& data)
+        : FilteringPlugin(data)
+    {
+    }
+
+    bool preRun() override { return compiler.getLangOpts().CPlusPlus; }
+
+    void run() override
+    {
+        if (preRun())
+        {
+            TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+        }
+    }
+
+    bool VisitNamespaceDecl(NamespaceDecl const* decl)
+    {
+        if (ignoreLocation(decl))
+        {
+            return true;
+        }
+        if (!decl->isAnonymousNamespace())
+        {
+            return true;
+        }
+        NamespaceDecl const* outer;
+        for (auto p = decl->getLexicalParent();; p = p->getLexicalParent())
+        {
+            outer = dyn_cast<NamespaceDecl>(p);
+            if (outer != nullptr)
+            {
+                break;
+            }
+            if (isa<TranslationUnitDecl>(p))
+            {
+                return true;
+            }
+        }
+        if (!outer->isAnonymousNamespace())
+        {
+            return true;
+        }
+        report(DiagnosticsEngine::Warning, "unnamed namespace directly nested in unnamed namespace",
+               decl->getLocation())
+            << decl->getSourceRange();
+        report(DiagnosticsEngine::Note, "outer namespace declared here", outer->getLocation())
+            << outer->getSourceRange();
+        return true;
+    }
+};
+
+loplugin::Plugin::Registration<NestedUnnamed> nestedunnamed("nestedunnamed");
+
+} // namespace
+
+#endif // LO_CLANG_SHARED_PLUGINS
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */