--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang-tools-extra/clang-tidy/readability/NamespaceCommentCheck.h	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,43 @@
+//===--- NamespaceCommentCheck.h - clang-tidy -------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_NAMESPACECOMMENTCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_NAMESPACECOMMENTCHECK_H
+
+#include "../ClangTidyCheck.h"
+#include "llvm/Support/Regex.h"
+
+namespace clang {
+namespace tidy {
+namespace readability {
+
+/// Checks that long namespaces have a closing comment.
+///
+/// http://llvm.org/docs/CodingStandards.html#namespace-indentation
+///
+/// https://google.github.io/styleguide/cppguide.html#Namespaces
+class NamespaceCommentCheck : public ClangTidyCheck {
+public:
+  NamespaceCommentCheck(StringRef Name, ClangTidyContext *Context);
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+  void storeOptions(ClangTidyOptions::OptionMap &Options) override;
+
+  llvm::Regex NamespaceCommentPattern;
+  const unsigned ShortNamespaceLines;
+  const unsigned SpacesBeforeComments;
+  llvm::SmallVector<SourceLocation, 4> Ends;
+};
+
+} // namespace readability
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_NAMESPACECOMMENTCHECK_H