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diff --git a/clang-tools-extra/cpp11-migrate/Core/CustomMatchers.h b/clang-tools-extra/cpp11-migrate/Core/CustomMatchers.h
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+++ b/clang-tools-extra/cpp11-migrate/Core/CustomMatchers.h
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+//===-- Core/CustomMatchers.h - Perf measurement helpers -----------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief This file provides custom matchers to be used by different
+/// transforms that requier the same matchers.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef CPP11_MIGRATE_CUSTOMMATCHERS_H
+#define CPP11_MIGRATE_CUSTOMMATCHERS_H
+
+#include "clang/ASTMatchers/ASTMatchers.h"
+
+namespace clang {
+namespace ast_matchers {
+
+/// \brief Matches declarations whose declaration context is the C++ standard
+/// library namespace \c std.
+///
+/// Note that inline namespaces are silently ignored during the lookup since
+/// both libstdc++ and libc++ are known to use them for versioning purposes.
+///
+/// Given
+/// \code
+///   namespace ns {
+///     struct my_type {};
+///     using namespace std;
+///   }
+///
+///   using std::vector;
+///   using ns::my_type;
+///   using ns::list;
+/// \endcode
+/// usingDecl(hasAnyUsingShadowDecl(hasTargetDecl(isFromStdNamespace())))
+///   matches "using std::vector" and "using ns::list".
+AST_MATCHER(Decl, isFromStdNamespace) {
+  const DeclContext *D = Node.getDeclContext();
+
+  while (D->isInlineNamespace())
+    D = D->getParent();
+
+  if (!D->isNamespace() || !D->getParent()->isTranslationUnit())
+    return false;
+
+  const IdentifierInfo *Info = cast<NamespaceDecl>(D)->getIdentifier();
+
+  return Info && Info->isStr("std");
+}
+} // namespace ast_matchers
+} // namespace clang
+
+#endif // CPP11_MIGRATE_CUSTOMMATCHERS_H