Export clang-format16 via ydblib project

6e6be3a95868fde888d801b7590af4044049563f

1 files changed, 601 insertions, 0 deletions

diff --git a/contrib/libs/clang16/lib/Tooling/Refactoring/Rename/USRLocFinder.cpp b/contrib/libs/clang16/lib/Tooling/Refactoring/Rename/USRLocFinder.cpp
new file mode 100644
index 0000000000..aecfffcbef
--- /dev/null
+++ b/contrib/libs/clang16/lib/Tooling/Refactoring/Rename/USRLocFinder.cpp
@@ -0,0 +1,601 @@
+//===--- USRLocFinder.cpp - Clang refactoring library ---------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Methods for finding all instances of a USR. Our strategy is very
+/// simple; we just compare the USR at every relevant AST node with the one
+/// provided.
+///
+//===----------------------------------------------------------------------===//
+
+#include "clang/Tooling/Refactoring/Rename/USRLocFinder.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/ParentMapContext.h"
+#include "clang/AST/RecursiveASTVisitor.h"
+#include "clang/Basic/LLVM.h"
+#include "clang/Basic/SourceLocation.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Lex/Lexer.h"
+#include "clang/Tooling/Refactoring/Lookup.h"
+#include "clang/Tooling/Refactoring/RecursiveSymbolVisitor.h"
+#include "clang/Tooling/Refactoring/Rename/SymbolName.h"
+#include "clang/Tooling/Refactoring/Rename/USRFinder.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Casting.h"
+#include <cstddef>
+#include <set>
+#include <string>
+#include <vector>
+
+using namespace llvm;
+
+namespace clang {
+namespace tooling {
+
+namespace {
+
+// Returns true if the given Loc is valid for edit. We don't edit the
+// SourceLocations that are valid or in temporary buffer.
+bool IsValidEditLoc(const clang::SourceManager& SM, clang::SourceLocation Loc) {
+  if (Loc.isInvalid())
+    return false;
+  const clang::FullSourceLoc FullLoc(Loc, SM);
+  std::pair<clang::FileID, unsigned> FileIdAndOffset =
+      FullLoc.getSpellingLoc().getDecomposedLoc();
+  return SM.getFileEntryForID(FileIdAndOffset.first) != nullptr;
+}
+
+// This visitor recursively searches for all instances of a USR in a
+// translation unit and stores them for later usage.
+class USRLocFindingASTVisitor
+    : public RecursiveSymbolVisitor<USRLocFindingASTVisitor> {
+public:
+  explicit USRLocFindingASTVisitor(const std::vector<std::string> &USRs,
+                                   StringRef PrevName,
+                                   const ASTContext &Context)
+      : RecursiveSymbolVisitor(Context.getSourceManager(),
+                               Context.getLangOpts()),
+        USRSet(USRs.begin(), USRs.end()), PrevName(PrevName), Context(Context) {
+  }
+
+  bool visitSymbolOccurrence(const NamedDecl *ND,
+                             ArrayRef<SourceRange> NameRanges) {
+    if (USRSet.find(getUSRForDecl(ND)) != USRSet.end()) {
+      assert(NameRanges.size() == 1 &&
+             "Multiple name pieces are not supported yet!");
+      SourceLocation Loc = NameRanges[0].getBegin();
+      const SourceManager &SM = Context.getSourceManager();
+      // TODO: Deal with macro occurrences correctly.
+      if (Loc.isMacroID())
+        Loc = SM.getSpellingLoc(Loc);
+      checkAndAddLocation(Loc);
+    }
+    return true;
+  }
+
+  // Non-visitors:
+
+  /// Returns a set of unique symbol occurrences. Duplicate or
+  /// overlapping occurrences are erroneous and should be reported!
+  SymbolOccurrences takeOccurrences() { return std::move(Occurrences); }
+
+private:
+  void checkAndAddLocation(SourceLocation Loc) {
+    const SourceLocation BeginLoc = Loc;
+    const SourceLocation EndLoc = Lexer::getLocForEndOfToken(
+        BeginLoc, 0, Context.getSourceManager(), Context.getLangOpts());
+    StringRef TokenName =
+        Lexer::getSourceText(CharSourceRange::getTokenRange(BeginLoc, EndLoc),
+                             Context.getSourceManager(), Context.getLangOpts());
+    size_t Offset = TokenName.find(PrevName.getNamePieces()[0]);
+
+    // The token of the source location we find actually has the old
+    // name.
+    if (Offset != StringRef::npos)
+      Occurrences.emplace_back(PrevName, SymbolOccurrence::MatchingSymbol,
+                               BeginLoc.getLocWithOffset(Offset));
+  }
+
+  const std::set<std::string> USRSet;
+  const SymbolName PrevName;
+  SymbolOccurrences Occurrences;
+  const ASTContext &Context;
+};
+
+SourceLocation StartLocationForType(TypeLoc TL) {
+  // For elaborated types (e.g. `struct a::A`) we want the portion after the
+  // `struct` but including the namespace qualifier, `a::`.
+  if (auto ElaboratedTypeLoc = TL.getAs<clang::ElaboratedTypeLoc>()) {
+    NestedNameSpecifierLoc NestedNameSpecifier =
+        ElaboratedTypeLoc.getQualifierLoc();
+    if (NestedNameSpecifier.getNestedNameSpecifier())
+      return NestedNameSpecifier.getBeginLoc();
+    TL = TL.getNextTypeLoc();
+  }
+  return TL.getBeginLoc();
+}
+
+SourceLocation EndLocationForType(TypeLoc TL) {
+  // Dig past any namespace or keyword qualifications.
+  while (TL.getTypeLocClass() == TypeLoc::Elaborated ||
+         TL.getTypeLocClass() == TypeLoc::Qualified)
+    TL = TL.getNextTypeLoc();
+
+  // The location for template specializations (e.g. Foo<int>) includes the
+  // templated types in its location range.  We want to restrict this to just
+  // before the `<` character.
+  if (TL.getTypeLocClass() == TypeLoc::TemplateSpecialization) {
+    return TL.castAs<TemplateSpecializationTypeLoc>()
+        .getLAngleLoc()
+        .getLocWithOffset(-1);
+  }
+  return TL.getEndLoc();
+}
+
+NestedNameSpecifier *GetNestedNameForType(TypeLoc TL) {
+  // Dig past any keyword qualifications.
+  while (TL.getTypeLocClass() == TypeLoc::Qualified)
+    TL = TL.getNextTypeLoc();
+
+  // For elaborated types (e.g. `struct a::A`) we want the portion after the
+  // `struct` but including the namespace qualifier, `a::`.
+  if (auto ElaboratedTypeLoc = TL.getAs<clang::ElaboratedTypeLoc>())
+    return ElaboratedTypeLoc.getQualifierLoc().getNestedNameSpecifier();
+  return nullptr;
+}
+
+// Find all locations identified by the given USRs for rename.
+//
+// This class will traverse the AST and find every AST node whose USR is in the
+// given USRs' set.
+class RenameLocFinder : public RecursiveASTVisitor<RenameLocFinder> {
+public:
+  RenameLocFinder(llvm::ArrayRef<std::string> USRs, ASTContext &Context)
+      : USRSet(USRs.begin(), USRs.end()), Context(Context) {}
+
+  // A structure records all information of a symbol reference being renamed.
+  // We try to add as few prefix qualifiers as possible.
+  struct RenameInfo {
+    // The begin location of a symbol being renamed.
+    SourceLocation Begin;
+    // The end location of a symbol being renamed.
+    SourceLocation End;
+    // The declaration of a symbol being renamed (can be nullptr).
+    const NamedDecl *FromDecl;
+    // The declaration in which the nested name is contained (can be nullptr).
+    const Decl *Context;
+    // The nested name being replaced (can be nullptr).
+    const NestedNameSpecifier *Specifier;
+    // Determine whether the prefix qualifiers of the NewName should be ignored.
+    // Normally, we set it to true for the symbol declaration and definition to
+    // avoid adding prefix qualifiers.
+    // For example, if it is true and NewName is "a::b::foo", then the symbol
+    // occurrence which the RenameInfo points to will be renamed to "foo".
+    bool IgnorePrefixQualifers;
+  };
+
+  bool VisitNamedDecl(const NamedDecl *Decl) {
+    // UsingDecl has been handled in other place.
+    if (llvm::isa<UsingDecl>(Decl))
+      return true;
+
+    // DestructorDecl has been handled in Typeloc.
+    if (llvm::isa<CXXDestructorDecl>(Decl))
+      return true;
+
+    if (Decl->isImplicit())
+      return true;
+
+    if (isInUSRSet(Decl)) {
+      // For the case of renaming an alias template, we actually rename the
+      // underlying alias declaration of the template.
+      if (const auto* TAT = dyn_cast<TypeAliasTemplateDecl>(Decl))
+        Decl = TAT->getTemplatedDecl();
+
+      auto StartLoc = Decl->getLocation();
+      auto EndLoc = StartLoc;
+      if (IsValidEditLoc(Context.getSourceManager(), StartLoc)) {
+        RenameInfo Info = {StartLoc,
+                           EndLoc,
+                           /*FromDecl=*/nullptr,
+                           /*Context=*/nullptr,
+                           /*Specifier=*/nullptr,
+                           /*IgnorePrefixQualifers=*/true};
+        RenameInfos.push_back(Info);
+      }
+    }
+    return true;
+  }
+
+  bool VisitMemberExpr(const MemberExpr *Expr) {
+    const NamedDecl *Decl = Expr->getFoundDecl();
+    auto StartLoc = Expr->getMemberLoc();
+    auto EndLoc = Expr->getMemberLoc();
+    if (isInUSRSet(Decl)) {
+      RenameInfos.push_back({StartLoc, EndLoc,
+                            /*FromDecl=*/nullptr,
+                            /*Context=*/nullptr,
+                            /*Specifier=*/nullptr,
+                            /*IgnorePrefixQualifiers=*/true});
+    }
+    return true;
+  }
+
+  bool VisitDesignatedInitExpr(const DesignatedInitExpr *E) {
+    for (const DesignatedInitExpr::Designator &D : E->designators()) {
+      if (D.isFieldDesignator() && D.getField()) {
+        const FieldDecl *Decl = D.getField();
+        if (isInUSRSet(Decl)) {
+          auto StartLoc = D.getFieldLoc();
+          auto EndLoc = D.getFieldLoc();
+          RenameInfos.push_back({StartLoc, EndLoc,
+                                 /*FromDecl=*/nullptr,
+                                 /*Context=*/nullptr,
+                                 /*Specifier=*/nullptr,
+                                 /*IgnorePrefixQualifiers=*/true});
+        }
+      }
+    }
+    return true;
+  }
+
+  bool VisitCXXConstructorDecl(const CXXConstructorDecl *CD) {
+    // Fix the constructor initializer when renaming class members.
+    for (const auto *Initializer : CD->inits()) {
+      // Ignore implicit initializers.
+      if (!Initializer->isWritten())
+        continue;
+
+      if (const FieldDecl *FD = Initializer->getMember()) {
+        if (isInUSRSet(FD)) {
+          auto Loc = Initializer->getSourceLocation();
+          RenameInfos.push_back({Loc, Loc,
+                                 /*FromDecl=*/nullptr,
+                                 /*Context=*/nullptr,
+                                 /*Specifier=*/nullptr,
+                                 /*IgnorePrefixQualifiers=*/true});
+        }
+      }
+    }
+    return true;
+  }
+
+  bool VisitDeclRefExpr(const DeclRefExpr *Expr) {
+    const NamedDecl *Decl = Expr->getFoundDecl();
+    // Get the underlying declaration of the shadow declaration introduced by a
+    // using declaration.
+    if (auto *UsingShadow = llvm::dyn_cast<UsingShadowDecl>(Decl)) {
+      Decl = UsingShadow->getTargetDecl();
+    }
+
+    auto StartLoc = Expr->getBeginLoc();
+    // For template function call expressions like `foo<int>()`, we want to
+    // restrict the end of location to just before the `<` character.
+    SourceLocation EndLoc = Expr->hasExplicitTemplateArgs()
+                                ? Expr->getLAngleLoc().getLocWithOffset(-1)
+                                : Expr->getEndLoc();
+
+    if (const auto *MD = llvm::dyn_cast<CXXMethodDecl>(Decl)) {
+      if (isInUSRSet(MD)) {
+        // Handle renaming static template class methods, we only rename the
+        // name without prefix qualifiers and restrict the source range to the
+        // name.
+        RenameInfos.push_back({EndLoc, EndLoc,
+                               /*FromDecl=*/nullptr,
+                               /*Context=*/nullptr,
+                               /*Specifier=*/nullptr,
+                               /*IgnorePrefixQualifiers=*/true});
+        return true;
+      }
+    }
+
+    // In case of renaming an enum declaration, we have to explicitly handle
+    // unscoped enum constants referenced in expressions (e.g.
+    // "auto r = ns1::ns2::Green" where Green is an enum constant of an unscoped
+    // enum decl "ns1::ns2::Color") as these enum constants cannot be caught by
+    // TypeLoc.
+    if (const auto *T = llvm::dyn_cast<EnumConstantDecl>(Decl)) {
+      // FIXME: Handle the enum constant without prefix qualifiers (`a = Green`)
+      // when renaming an unscoped enum declaration with a new namespace.
+      if (!Expr->hasQualifier())
+        return true;
+
+      if (const auto *ED =
+              llvm::dyn_cast_or_null<EnumDecl>(getClosestAncestorDecl(*T))) {
+        if (ED->isScoped())
+          return true;
+        Decl = ED;
+      }
+      // The current fix would qualify "ns1::ns2::Green" as
+      // "ns1::ns2::Color::Green".
+      //
+      // Get the EndLoc of the replacement by moving 1 character backward (
+      // to exclude the last '::').
+      //
+      //    ns1::ns2::Green;
+      //    ^      ^^
+      // BeginLoc  |EndLoc of the qualifier
+      //           new EndLoc
+      EndLoc = Expr->getQualifierLoc().getEndLoc().getLocWithOffset(-1);
+      assert(EndLoc.isValid() &&
+             "The enum constant should have prefix qualifers.");
+    }
+    if (isInUSRSet(Decl) &&
+        IsValidEditLoc(Context.getSourceManager(), StartLoc)) {
+      RenameInfo Info = {StartLoc,
+                         EndLoc,
+                         Decl,
+                         getClosestAncestorDecl(*Expr),
+                         Expr->getQualifier(),
+                         /*IgnorePrefixQualifers=*/false};
+      RenameInfos.push_back(Info);
+    }
+
+    return true;
+  }
+
+  bool VisitUsingDecl(const UsingDecl *Using) {
+    for (const auto *UsingShadow : Using->shadows()) {
+      if (isInUSRSet(UsingShadow->getTargetDecl())) {
+        UsingDecls.push_back(Using);
+        break;
+      }
+    }
+    return true;
+  }
+
+  bool VisitNestedNameSpecifierLocations(NestedNameSpecifierLoc NestedLoc) {
+    if (!NestedLoc.getNestedNameSpecifier()->getAsType())
+      return true;
+
+    if (const auto *TargetDecl =
+            getSupportedDeclFromTypeLoc(NestedLoc.getTypeLoc())) {
+      if (isInUSRSet(TargetDecl)) {
+        RenameInfo Info = {NestedLoc.getBeginLoc(),
+                           EndLocationForType(NestedLoc.getTypeLoc()),
+                           TargetDecl,
+                           getClosestAncestorDecl(NestedLoc),
+                           NestedLoc.getNestedNameSpecifier()->getPrefix(),
+                           /*IgnorePrefixQualifers=*/false};
+        RenameInfos.push_back(Info);
+      }
+    }
+    return true;
+  }
+
+  bool VisitTypeLoc(TypeLoc Loc) {
+    auto Parents = Context.getParents(Loc);
+    TypeLoc ParentTypeLoc;
+    if (!Parents.empty()) {
+      // Handle cases of nested name specificier locations.
+      //
+      // The VisitNestedNameSpecifierLoc interface is not impelmented in
+      // RecursiveASTVisitor, we have to handle it explicitly.
+      if (const auto *NSL = Parents[0].get<NestedNameSpecifierLoc>()) {
+        VisitNestedNameSpecifierLocations(*NSL);
+        return true;
+      }
+
+      if (const auto *TL = Parents[0].get<TypeLoc>())
+        ParentTypeLoc = *TL;
+    }
+
+    // Handle the outermost TypeLoc which is directly linked to the interesting
+    // declaration and don't handle nested name specifier locations.
+    if (const auto *TargetDecl = getSupportedDeclFromTypeLoc(Loc)) {
+      if (isInUSRSet(TargetDecl)) {
+        // Only handle the outermost typeLoc.
+        //
+        // For a type like "a::Foo", there will be two typeLocs for it.
+        // One ElaboratedType, the other is RecordType:
+        //
+        //   ElaboratedType 0x33b9390 'a::Foo' sugar
+        //   `-RecordType 0x338fef0 'class a::Foo'
+        //     `-CXXRecord 0x338fe58 'Foo'
+        //
+        // Skip if this is an inner typeLoc.
+        if (!ParentTypeLoc.isNull() &&
+            isInUSRSet(getSupportedDeclFromTypeLoc(ParentTypeLoc)))
+          return true;
+
+        auto StartLoc = StartLocationForType(Loc);
+        auto EndLoc = EndLocationForType(Loc);
+        if (IsValidEditLoc(Context.getSourceManager(), StartLoc)) {
+          RenameInfo Info = {StartLoc,
+                             EndLoc,
+                             TargetDecl,
+                             getClosestAncestorDecl(Loc),
+                             GetNestedNameForType(Loc),
+                             /*IgnorePrefixQualifers=*/false};
+          RenameInfos.push_back(Info);
+        }
+        return true;
+      }
+    }
+
+    // Handle specific template class specialiation cases.
+    if (const auto *TemplateSpecType =
+            dyn_cast<TemplateSpecializationType>(Loc.getType())) {
+      TypeLoc TargetLoc = Loc;
+      if (!ParentTypeLoc.isNull()) {
+        if (llvm::isa<ElaboratedType>(ParentTypeLoc.getType()))
+          TargetLoc = ParentTypeLoc;
+      }
+
+      if (isInUSRSet(TemplateSpecType->getTemplateName().getAsTemplateDecl())) {
+        TypeLoc TargetLoc = Loc;
+        // FIXME: Find a better way to handle this case.
+        // For the qualified template class specification type like
+        // "ns::Foo<int>" in "ns::Foo<int>& f();", we want the parent typeLoc
+        // (ElaboratedType) of the TemplateSpecializationType in order to
+        // catch the prefix qualifiers "ns::".
+        if (!ParentTypeLoc.isNull() &&
+            llvm::isa<ElaboratedType>(ParentTypeLoc.getType()))
+          TargetLoc = ParentTypeLoc;
+
+        auto StartLoc = StartLocationForType(TargetLoc);
+        auto EndLoc = EndLocationForType(TargetLoc);
+        if (IsValidEditLoc(Context.getSourceManager(), StartLoc)) {
+          RenameInfo Info = {
+              StartLoc,
+              EndLoc,
+              TemplateSpecType->getTemplateName().getAsTemplateDecl(),
+              getClosestAncestorDecl(DynTypedNode::create(TargetLoc)),
+              GetNestedNameForType(TargetLoc),
+              /*IgnorePrefixQualifers=*/false};
+          RenameInfos.push_back(Info);
+        }
+      }
+    }
+    return true;
+  }
+
+  // Returns a list of RenameInfo.
+  const std::vector<RenameInfo> &getRenameInfos() const { return RenameInfos; }
+
+  // Returns a list of using declarations which are needed to update.
+  const std::vector<const UsingDecl *> &getUsingDecls() const {
+    return UsingDecls;
+  }
+
+private:
+  // Get the supported declaration from a given typeLoc. If the declaration type
+  // is not supported, returns nullptr.
+  const NamedDecl *getSupportedDeclFromTypeLoc(TypeLoc Loc) {
+    if (const auto* TT = Loc.getType()->getAs<clang::TypedefType>())
+      return TT->getDecl();
+    if (const auto *RD = Loc.getType()->getAsCXXRecordDecl())
+      return RD;
+    if (const auto *ED =
+            llvm::dyn_cast_or_null<EnumDecl>(Loc.getType()->getAsTagDecl()))
+      return ED;
+    return nullptr;
+  }
+
+  // Get the closest ancester which is a declaration of a given AST node.
+  template <typename ASTNodeType>
+  const Decl *getClosestAncestorDecl(const ASTNodeType &Node) {
+    auto Parents = Context.getParents(Node);
+    // FIXME: figure out how to handle it when there are multiple parents.
+    if (Parents.size() != 1)
+      return nullptr;
+    if (ASTNodeKind::getFromNodeKind<Decl>().isBaseOf(Parents[0].getNodeKind()))
+      return Parents[0].template get<Decl>();
+    return getClosestAncestorDecl(Parents[0]);
+  }
+
+  // Get the parent typeLoc of a given typeLoc. If there is no such parent,
+  // return nullptr.
+  const TypeLoc *getParentTypeLoc(TypeLoc Loc) const {
+    auto Parents = Context.getParents(Loc);
+    // FIXME: figure out how to handle it when there are multiple parents.
+    if (Parents.size() != 1)
+      return nullptr;
+    return Parents[0].get<TypeLoc>();
+  }
+
+  // Check whether the USR of a given Decl is in the USRSet.
+  bool isInUSRSet(const Decl *Decl) const {
+    auto USR = getUSRForDecl(Decl);
+    if (USR.empty())
+      return false;
+    return llvm::is_contained(USRSet, USR);
+  }
+
+  const std::set<std::string> USRSet;
+  ASTContext &Context;
+  std::vector<RenameInfo> RenameInfos;
+  // Record all interested using declarations which contains the using-shadow
+  // declarations of the symbol declarations being renamed.
+  std::vector<const UsingDecl *> UsingDecls;
+};
+
+} // namespace
+
+SymbolOccurrences getOccurrencesOfUSRs(ArrayRef<std::string> USRs,
+                                       StringRef PrevName, Decl *Decl) {
+  USRLocFindingASTVisitor Visitor(USRs, PrevName, Decl->getASTContext());
+  Visitor.TraverseDecl(Decl);
+  return Visitor.takeOccurrences();
+}
+
+std::vector<tooling::AtomicChange>
+createRenameAtomicChanges(llvm::ArrayRef<std::string> USRs,
+                          llvm::StringRef NewName, Decl *TranslationUnitDecl) {
+  RenameLocFinder Finder(USRs, TranslationUnitDecl->getASTContext());
+  Finder.TraverseDecl(TranslationUnitDecl);
+
+  const SourceManager &SM =
+      TranslationUnitDecl->getASTContext().getSourceManager();
+
+  std::vector<tooling::AtomicChange> AtomicChanges;
+  auto Replace = [&](SourceLocation Start, SourceLocation End,
+                     llvm::StringRef Text) {
+    tooling::AtomicChange ReplaceChange = tooling::AtomicChange(SM, Start);
+    llvm::Error Err = ReplaceChange.replace(
+        SM, CharSourceRange::getTokenRange(Start, End), Text);
+    if (Err) {
+      llvm::errs() << "Failed to add replacement to AtomicChange: "
+                   << llvm::toString(std::move(Err)) << "\n";
+      return;
+    }
+    AtomicChanges.push_back(std::move(ReplaceChange));
+  };
+
+  for (const auto &RenameInfo : Finder.getRenameInfos()) {
+    std::string ReplacedName = NewName.str();
+    if (RenameInfo.IgnorePrefixQualifers) {
+      // Get the name without prefix qualifiers from NewName.
+      size_t LastColonPos = NewName.find_last_of(':');
+      if (LastColonPos != std::string::npos)
+        ReplacedName = std::string(NewName.substr(LastColonPos + 1));
+    } else {
+      if (RenameInfo.FromDecl && RenameInfo.Context) {
+        if (!llvm::isa<clang::TranslationUnitDecl>(
+                RenameInfo.Context->getDeclContext())) {
+          ReplacedName = tooling::replaceNestedName(
+              RenameInfo.Specifier, RenameInfo.Begin,
+              RenameInfo.Context->getDeclContext(), RenameInfo.FromDecl,
+              NewName.startswith("::") ? NewName.str()
+                                       : ("::" + NewName).str());
+        } else {
+          // This fixes the case where type `T` is a parameter inside a function
+          // type (e.g. `std::function<void(T)>`) and the DeclContext of `T`
+          // becomes the translation unit. As a workaround, we simply use
+          // fully-qualified name here for all references whose `DeclContext` is
+          // the translation unit and ignore the possible existence of
+          // using-decls (in the global scope) that can shorten the replaced
+          // name.
+          llvm::StringRef ActualName = Lexer::getSourceText(
+              CharSourceRange::getTokenRange(
+                  SourceRange(RenameInfo.Begin, RenameInfo.End)),
+              SM, TranslationUnitDecl->getASTContext().getLangOpts());
+          // Add the leading "::" back if the name written in the code contains
+          // it.
+          if (ActualName.startswith("::") && !NewName.startswith("::")) {
+            ReplacedName = "::" + NewName.str();
+          }
+        }
+      }
+      // If the NewName contains leading "::", add it back.
+      if (NewName.startswith("::") && NewName.substr(2) == ReplacedName)
+        ReplacedName = NewName.str();
+    }
+    Replace(RenameInfo.Begin, RenameInfo.End, ReplacedName);
+  }
+
+  // Hanlde using declarations explicitly as "using a::Foo" don't trigger
+  // typeLoc for "a::Foo".
+  for (const auto *Using : Finder.getUsingDecls())
+    Replace(Using->getBeginLoc(), Using->getEndLoc(), "using " + NewName.str());
+
+  return AtomicChanges;
+}
+
+} // end namespace tooling
+} // end namespace clang