Imported Upstream version 6.10.0.49

Former-commit-id: 1d6753294b2993e1fbf92de9366bb9544db4189b

external/llvm-project/clang-tools-extra/clang-tidy/cert/DontModifyStdNamespaceCheck.cpp

@@ -0,0 +1,49 @@
+//===--- DontModifyStdNamespaceCheck.cpp - clang-tidy----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DontModifyStdNamespaceCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace cert {
+
+void DontModifyStdNamespaceCheck::registerMatchers(MatchFinder *Finder) {
+  if (!getLangOpts().CPlusPlus)
+    return;
+
+  Finder->addMatcher(
+      namespaceDecl(unless(isExpansionInSystemHeader()),
+                    anyOf(hasName("std"), hasName("posix")),
+                    has(decl(unless(anyOf(
+                        functionDecl(isExplicitTemplateSpecialization()),
+                        cxxRecordDecl(isExplicitTemplateSpecialization()))))))
+          .bind("nmspc"),
+      this);
+}
+
+void DontModifyStdNamespaceCheck::check(
+    const MatchFinder::MatchResult &Result) {
+  const auto *N = Result.Nodes.getNodeAs<NamespaceDecl>("nmspc");
+
+  // Only consider top level namespaces.
+  if (N->getParent() != Result.Context->getTranslationUnitDecl())
+    return;
+
+  diag(N->getLocation(),
+       "modification of %0 namespace can result in undefined behavior")
+      << N;
+}
+
+} // namespace cert
+} // namespace tidy
+} // namespace clang