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diff --git a/clang-tools-extra/clang-tidy/misc/NewDeleteOverloadsCheck.cpp b/clang-tools-extra/clang-tidy/misc/NewDeleteOverloadsCheck.cpp
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+//===--- NewDeleteOverloadsCheck.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 "NewDeleteOverloadsCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace {
+AST_MATCHER(FunctionDecl, isPlacementOverload) {
+  bool New;
+  switch (Node.getOverloadedOperator()) {
+  default:
+    return false;
+  case OO_New:
+  case OO_Array_New:
+    New = true;
+    break;
+  case OO_Delete:
+  case OO_Array_Delete:
+    New = false;
+    break;
+  }
+
+  // Variadic functions are always placement functions.
+  if (Node.isVariadic())
+    return true;
+
+  // Placement new is easy: it always has more than one parameter (the first
+  // parameter is always the size). If it's an overload of delete or delete[]
+  // that has only one parameter, it's never a placement delete.
+  if (New)
+    return Node.getNumParams() > 1;
+  if (Node.getNumParams() == 1)
+    return false;
+
+  // Placement delete is a little more challenging. They always have more than
+  // one parameter with the first parameter being a pointer. However, the
+  // second parameter can be a size_t for sized deallocation, and that is never
+  // a placement delete operator.
+  if (Node.getNumParams() <= 1 || Node.getNumParams() > 2)
+    return true;
+
+  const auto *FPT = Node.getType()->castAs<FunctionProtoType>();
+  ASTContext &Ctx = Node.getASTContext();
+  if (Ctx.getLangOpts().SizedDeallocation &&
+      Ctx.hasSameType(FPT->getParamType(1), Ctx.getSizeType()))
+    return false;
+
+  return true;
+}
+} // namespace
+
+namespace tidy {
+namespace misc {
+
+namespace {
+OverloadedOperatorKind getCorrespondingOverload(const FunctionDecl *FD) {
+  switch (FD->getOverloadedOperator()) {
+  default: break;
+  case OO_New:
+    return OO_Delete;
+  case OO_Delete:
+    return OO_New;
+  case OO_Array_New:
+    return OO_Array_Delete;
+  case OO_Array_Delete:
+    return OO_Array_New;
+  }
+  llvm_unreachable("Not an overloaded allocation operator");
+}
+
+const char *getOperatorName(OverloadedOperatorKind K) {
+  switch (K) {
+  default: break;
+  case OO_New:
+    return "operator new";
+  case OO_Delete:
+    return "operator delete";
+  case OO_Array_New:
+    return "operator new[]";
+  case OO_Array_Delete:
+    return "operator delete[]";
+  }
+  llvm_unreachable("Not an overloaded allocation operator");
+}
+
+bool areCorrespondingOverloads(const FunctionDecl *LHS,
+                               const FunctionDecl *RHS) {
+  return RHS->getOverloadedOperator() == getCorrespondingOverload(LHS);
+}
+
+bool hasCorrespondingOverloadInOneClass(const CXXRecordDecl *RD,
+                                        const CXXMethodDecl *MD) {
+  // Check the methods in the given class and accessible to derived classes.
+  for (const auto *BMD : RD->methods())
+    if (BMD->isOverloadedOperator() && BMD->getAccess() != AS_private &&
+        areCorrespondingOverloads(MD, BMD))
+      return true;
+
+  // Check base classes.
+  for (const auto &BS : RD->bases())
+    if (hasCorrespondingOverloadInOneClass(BS.getType()->getAsCXXRecordDecl(),
+                                           MD))
+      return true;
+
+  return false;
+}
+bool hasCorrespondingOverloadInBaseClass(const CXXMethodDecl *MD) {
+  // Get the parent class of the method; we do not need to care about checking
+  // the methods in this class as the caller has already done that by looking
+  // at the declaration contexts.
+  const CXXRecordDecl *RD = MD->getParent();
+
+  for (const auto &BS : RD->bases())
+    if (hasCorrespondingOverloadInOneClass(BS.getType()->getAsCXXRecordDecl(),
+                                           MD))
+      return true;
+
+  return false;
+}
+} // anonymous namespace
+
+void NewDeleteOverloadsCheck::registerMatchers(MatchFinder *Finder) {
+  if (!getLangOpts().CPlusPlus)
+    return;
+
+  // Match all operator new and operator delete overloads (including the array
+  // forms). Do not match implicit operators, placement operators, or
+  // deleted/private operators.
+  //
+  // Technically, trivially-defined operator delete seems like a reasonable
+  // thing to also skip. e.g., void operator delete(void *) {}
+  // However, I think it's more reasonable to warn in this case as the user
+  // should really be writing that as a deleted function.
+  Finder->addMatcher(
+      functionDecl(
+          unless(anyOf(isImplicit(), isPlacementOverload(), isDeleted(),
+                       cxxMethodDecl(isPrivate()))),
+          anyOf(hasOverloadedOperatorName("new"),
+                hasOverloadedOperatorName("new[]"),
+                hasOverloadedOperatorName("delete"),
+                hasOverloadedOperatorName("delete[]")))
+          .bind("func"),
+      this);
+}
+
+void NewDeleteOverloadsCheck::check(const MatchFinder::MatchResult &Result) {
+  // Add any matches we locate to the list of things to be checked at the
+  // end of the translation unit.
+  const auto *FD = Result.Nodes.getNodeAs<FunctionDecl>("func");
+  const CXXRecordDecl *RD = nullptr;
+  if (const auto *MD = dyn_cast<CXXMethodDecl>(FD))
+    RD = MD->getParent();
+  Overloads[RD].push_back(FD);
+}
+
+void NewDeleteOverloadsCheck::onEndOfTranslationUnit() {
+  // Walk over the list of declarations we've found to see if there is a
+  // corresponding overload at the same declaration context or within a base
+  // class. If there is not, add the element to the list of declarations to
+  // diagnose.
+  SmallVector<const FunctionDecl *, 4> Diagnose;
+  for (const auto &RP : Overloads) {
+    // We don't care about the CXXRecordDecl key in the map; we use it as a way
+    // to shard the overloads by declaration context to reduce the algorithmic
+    // complexity when searching for corresponding free store functions.
+    for (const auto *Overload : RP.second) {
+      const auto *Match = std::find_if(
+          RP.second.begin(), RP.second.end(), [&](const FunctionDecl *FD) {
+            if (FD == Overload)
+              return false;
+            // If the declaration contexts don't match, we don't
+            // need to check
+            // any further.
+            if (FD->getDeclContext() != Overload->getDeclContext())
+              return false;
+
+            // Since the declaration contexts match, see whether
+            // the current
+            // element is the corresponding operator.
+            if (!areCorrespondingOverloads(Overload, FD))
+              return false;
+
+            return true;
+          });
+
+      if (Match == RP.second.end()) {
+        // Check to see if there is a corresponding overload in a base class
+        // context. If there isn't, or if the overload is not a class member
+        // function, then we should diagnose.
+        const auto *MD = dyn_cast<CXXMethodDecl>(Overload);
+        if (!MD || !hasCorrespondingOverloadInBaseClass(MD))
+          Diagnose.push_back(Overload);
+      }
+    }
+  }
+
+  for (const auto *FD : Diagnose)
+    diag(FD->getLocation(), "declaration of %0 has no matching declaration "
+                            "of '%1' at the same scope")
+        << FD << getOperatorName(getCorrespondingOverload(FD));
+}
+
+} // namespace misc
+} // namespace tidy
+} // namespace clang