diff --git a/clang/include/clang/Parse/Parser.h b/clang/include/clang/Parse/Parser.h
index 00e4b980bf44a..ab6927130bc2b 100644
--- a/clang/include/clang/Parse/Parser.h
+++ b/clang/include/clang/Parse/Parser.h
@@ -29,28 +29,28 @@
 #include <stack>
 
 namespace clang {
-  class PragmaHandler;
-  class Scope;
-  class BalancedDelimiterTracker;
-  class CorrectionCandidateCallback;
-  class DeclGroupRef;
-  class DiagnosticBuilder;
-  struct LoopHint;
-  class Parser;
-  class ParsingDeclRAIIObject;
-  class ParsingDeclSpec;
-  class ParsingDeclarator;
-  class ParsingFieldDeclarator;
-  class ColonProtectionRAIIObject;
-  class InMessageExpressionRAIIObject;
-  class PoisonSEHIdentifiersRAIIObject;
-  class OMPClause;
-  class OpenACCClause;
-  class ObjCTypeParamList;
-  struct OMPTraitProperty;
-  struct OMPTraitSelector;
-  struct OMPTraitSet;
-  class OMPTraitInfo;
+class PragmaHandler;
+class Scope;
+class BalancedDelimiterTracker;
+class CorrectionCandidateCallback;
+class DeclGroupRef;
+class DiagnosticBuilder;
+struct LoopHint;
+class Parser;
+class ParsingDeclRAIIObject;
+class ParsingDeclSpec;
+class ParsingDeclarator;
+class ParsingFieldDeclarator;
+class ColonProtectionRAIIObject;
+class InMessageExpressionRAIIObject;
+class PoisonSEHIdentifiersRAIIObject;
+class OMPClause;
+class OpenACCClause;
+class ObjCTypeParamList;
+struct OMPTraitProperty;
+struct OMPTraitSelector;
+struct OMPTraitSet;
+class OMPTraitInfo;
 
 enum class AnnotatedNameKind {
   /// Annotation has failed and emitted an error.
@@ -153,571 +153,438 @@ enum class CXX11AttributeKind {
 /// parsing units of the grammar, productions are invoked to handle whatever has
 /// been read.
 ///
+/// \nosubgrouping
 class Parser : public CodeCompletionHandler {
+  // Table of Contents
+  // -----------------
+  // 1. Parsing (Parser.cpp)
+  // 2. C++ Class Inline Methods (ParseCXXInlineMethods.cpp)
+  // 3. Declarations (ParseDecl.cpp)
+  // 4. C++ Declarations (ParseDeclCXX.cpp)
+  // 5. Expressions (ParseExpr.cpp)
+  // 6. C++ Expressions (ParseExprCXX.cpp)
+  // 7. HLSL Constructs (ParseHLSL.cpp)
+  // 8. Initializers (ParseInit.cpp)
+  // 9. Objective-C Constructs (ParseObjc.cpp)
+  // 10. OpenACC Constructs (ParseOpenACC.cpp)
+  // 11. OpenMP Constructs (ParseOpenMP.cpp)
+  // 12. Pragmas (ParsePragma.cpp)
+  // 13. Statements (ParseStmt.cpp)
+  // 14. `inline asm` Statement (ParseStmtAsm.cpp)
+  // 15. C++ Templates (ParseTemplate.cpp)
+  // 16. Tentative Parsing (ParseTentative.cpp)
+
+  /// \name Parsing
+  /// Implementations are in Parser.cpp
+  ///@{
+
+public:
   friend class ColonProtectionRAIIObject;
-  friend class ParsingOpenMPDirectiveRAII;
-  friend class ParsingOpenACCDirectiveRAII;
-  friend class InMessageExpressionRAIIObject;
-  friend class OffsetOfStateRAIIObject;
   friend class PoisonSEHIdentifiersRAIIObject;
-  friend class ObjCDeclContextSwitch;
   friend class ParenBraceBracketBalancer;
   friend class BalancedDelimiterTracker;
 
-  Preprocessor &PP;
+  Parser(Preprocessor &PP, Sema &Actions, bool SkipFunctionBodies);
+  ~Parser() override;
 
-  /// Tok - The current token we are peeking ahead.  All parsing methods assume
-  /// that this is valid.
-  Token Tok;
+  const LangOptions &getLangOpts() const { return PP.getLangOpts(); }
+  const TargetInfo &getTargetInfo() const { return PP.getTargetInfo(); }
+  Preprocessor &getPreprocessor() const { return PP; }
+  Sema &getActions() const { return Actions; }
+  AttributeFactory &getAttrFactory() { return AttrFactory; }
 
-  // PrevTokLocation - The location of the token we previously
-  // consumed. This token is used for diagnostics where we expected to
-  // see a token following another token (e.g., the ';' at the end of
-  // a statement).
-  SourceLocation PrevTokLocation;
+  const Token &getCurToken() const { return Tok; }
+  Scope *getCurScope() const { return Actions.getCurScope(); }
 
-  /// Tracks an expected type for the current token when parsing an expression.
-  /// Used by code completion for ranking.
-  PreferredTypeBuilder PreferredType;
+  void incrementMSManglingNumber() const {
+    return Actions.incrementMSManglingNumber();
+  }
 
-  unsigned short ParenCount = 0, BracketCount = 0, BraceCount = 0;
-  unsigned short MisplacedModuleBeginCount = 0;
+  // Type forwarding.  All of these are statically 'void*', but they may all be
+  // different actual classes based on the actions in place.
+  typedef OpaquePtr<DeclGroupRef> DeclGroupPtrTy;
+  typedef OpaquePtr<TemplateName> TemplateTy;
 
-  /// Actions - These are the callbacks we invoke as we parse various constructs
-  /// in the file.
-  Sema &Actions;
+  /// Initialize - Warm up the parser.
+  ///
+  void Initialize();
 
-  DiagnosticsEngine &Diags;
+  /// Parse the first top-level declaration in a translation unit.
+  ///
+  /// \verbatim
+  ///   translation-unit:
+  /// [C]     external-declaration
+  /// [C]     translation-unit external-declaration
+  /// [C++]   top-level-declaration-seq[opt]
+  /// [C++20] global-module-fragment[opt] module-declaration
+  ///                 top-level-declaration-seq[opt] private-module-fragment[opt]
+  /// \endverbatim
+  ///
+  /// Note that in C, it is an error if there is no first declaration.
+  bool ParseFirstTopLevelDecl(DeclGroupPtrTy &Result,
+                              Sema::ModuleImportState &ImportState);
 
-  StackExhaustionHandler StackHandler;
+  /// ParseTopLevelDecl - Parse one top-level declaration, return whatever the
+  /// action tells us to.  This returns true if the EOF was encountered.
+  ///
+  /// \verbatim
+  ///   top-level-declaration:
+  ///           declaration
+  /// [C++20]   module-import-declaration
+  /// \endverbatim
+  bool ParseTopLevelDecl(DeclGroupPtrTy &Result,
+                         Sema::ModuleImportState &ImportState);
+  bool ParseTopLevelDecl() {
+    DeclGroupPtrTy Result;
+    Sema::ModuleImportState IS = Sema::ModuleImportState::NotACXX20Module;
+    return ParseTopLevelDecl(Result, IS);
+  }
 
-  /// ScopeCache - Cache scopes to reduce malloc traffic.
-  static constexpr int ScopeCacheSize = 16;
-  unsigned NumCachedScopes;
-  Scope *ScopeCache[ScopeCacheSize];
+  /// ConsumeToken - Consume the current 'peek token' and lex the next one.
+  /// This does not work with special tokens: string literals, code completion,
+  /// annotation tokens and balanced tokens must be handled using the specific
+  /// consume methods.
+  /// Returns the location of the consumed token.
+  SourceLocation ConsumeToken() {
+    assert(!isTokenSpecial() &&
+           "Should consume special tokens with Consume*Token");
+    PrevTokLocation = Tok.getLocation();
+    PP.Lex(Tok);
+    return PrevTokLocation;
+  }
 
-  /// Identifiers used for SEH handling in Borland. These are only
-  /// allowed in particular circumstances
-  // __except block
-  IdentifierInfo *Ident__exception_code,
-                 *Ident___exception_code,
-                 *Ident_GetExceptionCode;
-  // __except filter expression
-  IdentifierInfo *Ident__exception_info,
-                 *Ident___exception_info,
-                 *Ident_GetExceptionInfo;
-  // __finally
-  IdentifierInfo *Ident__abnormal_termination,
-                 *Ident___abnormal_termination,
-                 *Ident_AbnormalTermination;
+  bool TryConsumeToken(tok::TokenKind Expected) {
+    if (Tok.isNot(Expected))
+      return false;
+    assert(!isTokenSpecial() &&
+           "Should consume special tokens with Consume*Token");
+    PrevTokLocation = Tok.getLocation();
+    PP.Lex(Tok);
+    return true;
+  }
 
-  /// Contextual keywords for Microsoft extensions.
-  IdentifierInfo *Ident__except;
-  mutable IdentifierInfo *Ident_sealed;
-  mutable IdentifierInfo *Ident_abstract;
+  bool TryConsumeToken(tok::TokenKind Expected, SourceLocation &Loc) {
+    if (!TryConsumeToken(Expected))
+      return false;
+    Loc = PrevTokLocation;
+    return true;
+  }
 
-  /// Ident_super - IdentifierInfo for "super", to support fast
-  /// comparison.
-  IdentifierInfo *Ident_super;
-  /// Ident_vector, Ident_bool, Ident_Bool - cached IdentifierInfos for "vector"
-  /// and "bool" fast comparison.  Only present if AltiVec or ZVector are
-  /// enabled.
-  IdentifierInfo *Ident_vector;
-  IdentifierInfo *Ident_bool;
-  IdentifierInfo *Ident_Bool;
-  /// Ident_pixel - cached IdentifierInfos for "pixel" fast comparison.
-  /// Only present if AltiVec enabled.
-  IdentifierInfo *Ident_pixel;
+  /// ConsumeAnyToken - Dispatch to the right Consume* method based on the
+  /// current token type.  This should only be used in cases where the type of
+  /// the token really isn't known, e.g. in error recovery.
+  SourceLocation ConsumeAnyToken(bool ConsumeCodeCompletionTok = false) {
+    if (isTokenParen())
+      return ConsumeParen();
+    if (isTokenBracket())
+      return ConsumeBracket();
+    if (isTokenBrace())
+      return ConsumeBrace();
+    if (isTokenStringLiteral())
+      return ConsumeStringToken();
+    if (Tok.is(tok::code_completion))
+      return ConsumeCodeCompletionTok ? ConsumeCodeCompletionToken()
+                                      : handleUnexpectedCodeCompletionToken();
+    if (Tok.isAnnotation())
+      return ConsumeAnnotationToken();
+    return ConsumeToken();
+  }
 
-  /// Objective-C contextual keywords.
-  IdentifierInfo *Ident_instancetype;
+  SourceLocation getEndOfPreviousToken() {
+    return PP.getLocForEndOfToken(PrevTokLocation);
+  }
 
-  /// Identifier for "introduced".
-  IdentifierInfo *Ident_introduced;
+  /// GetLookAheadToken - This peeks ahead N tokens and returns that token
+  /// without consuming any tokens.  LookAhead(0) returns 'Tok', LookAhead(1)
+  /// returns the token after Tok, etc.
+  ///
+  /// Note that this differs from the Preprocessor's LookAhead method, because
+  /// the Parser always has one token lexed that the preprocessor doesn't.
+  ///
+  const Token &GetLookAheadToken(unsigned N) {
+    if (N == 0 || Tok.is(tok::eof))
+      return Tok;
+    return PP.LookAhead(N - 1);
+  }
 
-  /// Identifier for "deprecated".
-  IdentifierInfo *Ident_deprecated;
+  /// NextToken - This peeks ahead one token and returns it without
+  /// consuming it.
+  const Token &NextToken() { return PP.LookAhead(0); }
 
-  /// Identifier for "obsoleted".
-  IdentifierInfo *Ident_obsoleted;
+  /// getTypeAnnotation - Read a parsed type out of an annotation token.
+  static TypeResult getTypeAnnotation(const Token &Tok) {
+    if (!Tok.getAnnotationValue())
+      return TypeError();
+    return ParsedType::getFromOpaquePtr(Tok.getAnnotationValue());
+  }
 
-  /// Identifier for "unavailable".
-  IdentifierInfo *Ident_unavailable;
+  /// TryAnnotateTypeOrScopeToken - If the current token position is on a
+  /// typename (possibly qualified in C++) or a C++ scope specifier not followed
+  /// by a typename, TryAnnotateTypeOrScopeToken will replace one or more tokens
+  /// with a single annotation token representing the typename or C++ scope
+  /// respectively.
+  /// This simplifies handling of C++ scope specifiers and allows efficient
+  /// backtracking without the need to re-parse and resolve nested-names and
+  /// typenames.
+  /// It will mainly be called when we expect to treat identifiers as typenames
+  /// (if they are typenames). For example, in C we do not expect identifiers
+  /// inside expressions to be treated as typenames so it will not be called
+  /// for expressions in C.
+  /// The benefit for C/ObjC is that a typename will be annotated and
+  /// Actions.getTypeName will not be needed to be called again (e.g.
+  /// getTypeName will not be called twice, once to check whether we have a
+  /// declaration specifier, and another one to get the actual type inside
+  /// ParseDeclarationSpecifiers).
+  ///
+  /// This returns true if an error occurred.
+  ///
+  /// Note that this routine emits an error if you call it with ::new or
+  /// ::delete as the current tokens, so only call it in contexts where these
+  /// are invalid.
+  bool
+  TryAnnotateTypeOrScopeToken(ImplicitTypenameContext AllowImplicitTypename =
+                                  ImplicitTypenameContext::No);
 
-  /// Identifier for "message".
-  IdentifierInfo *Ident_message;
+  /// Try to annotate a type or scope token, having already parsed an
+  /// optional scope specifier. \p IsNewScope should be \c true unless the scope
+  /// specifier was extracted from an existing tok::annot_cxxscope annotation.
+  bool TryAnnotateTypeOrScopeTokenAfterScopeSpec(
+      CXXScopeSpec &SS, bool IsNewScope,
+      ImplicitTypenameContext AllowImplicitTypename);
 
-  /// Identifier for "strict".
-  IdentifierInfo *Ident_strict;
+  /// TryAnnotateScopeToken - Like TryAnnotateTypeOrScopeToken but only
+  /// annotates C++ scope specifiers and template-ids.  This returns
+  /// true if there was an error that could not be recovered from.
+  ///
+  /// Note that this routine emits an error if you call it with ::new or
+  /// ::delete as the current tokens, so only call it in contexts where these
+  /// are invalid.
+  bool TryAnnotateCXXScopeToken(bool EnteringContext = false);
 
-  /// Identifier for "replacement".
-  IdentifierInfo *Ident_replacement;
+  bool MightBeCXXScopeToken() {
+    return getLangOpts().CPlusPlus &&
+           (Tok.is(tok::identifier) || Tok.is(tok::coloncolon) ||
+            (Tok.is(tok::annot_template_id) &&
+             NextToken().is(tok::coloncolon)) ||
+            Tok.is(tok::kw_decltype) || Tok.is(tok::kw___super));
+  }
+  bool TryAnnotateOptionalCXXScopeToken(bool EnteringContext = false) {
+    return MightBeCXXScopeToken() && TryAnnotateCXXScopeToken(EnteringContext);
+  }
 
-  /// Identifier for "environment".
-  IdentifierInfo *Ident_environment;
+  //===--------------------------------------------------------------------===//
+  // Scope manipulation
 
-  /// Identifiers used by the 'external_source_symbol' attribute.
-  IdentifierInfo *Ident_language, *Ident_defined_in,
-      *Ident_generated_declaration, *Ident_USR;
+  /// ParseScope - Introduces a new scope for parsing. The kind of
+  /// scope is determined by ScopeFlags. Objects of this type should
+  /// be created on the stack to coincide with the position where the
+  /// parser enters the new scope, and this object's constructor will
+  /// create that new scope. Similarly, once the object is destroyed
+  /// the parser will exit the scope.
+  class ParseScope {
+    Parser *Self;
+    ParseScope(const ParseScope &) = delete;
+    void operator=(const ParseScope &) = delete;
 
-  /// C++11 contextual keywords.
-  mutable IdentifierInfo *Ident_final;
-  mutable IdentifierInfo *Ident_GNU_final;
-  mutable IdentifierInfo *Ident_override;
+  public:
+    // ParseScope - Construct a new object to manage a scope in the
+    // parser Self where the new Scope is created with the flags
+    // ScopeFlags, but only when we aren't about to enter a compound statement.
+    ParseScope(Parser *Self, unsigned ScopeFlags, bool EnteredScope = true,
+               bool BeforeCompoundStmt = false)
+        : Self(Self) {
+      if (EnteredScope && !BeforeCompoundStmt)
+        Self->EnterScope(ScopeFlags);
+      else {
+        if (BeforeCompoundStmt)
+          Self->incrementMSManglingNumber();
 
-  // C++2a contextual keywords.
-  mutable IdentifierInfo *Ident_import;
-  mutable IdentifierInfo *Ident_module;
+        this->Self = nullptr;
+      }
+    }
 
-  // C++ type trait keywords that can be reverted to identifiers and still be
-  // used as type traits.
-  llvm::SmallDenseMap<IdentifierInfo *, tok::TokenKind> RevertibleTypeTraits;
+    // Exit - Exit the scope associated with this object now, rather
+    // than waiting until the object is destroyed.
+    void Exit() {
+      if (Self) {
+        Self->ExitScope();
+        Self = nullptr;
+      }
+    }
 
-  std::unique_ptr<PragmaHandler> AlignHandler;
-  std::unique_ptr<PragmaHandler> GCCVisibilityHandler;
-  std::unique_ptr<PragmaHandler> OptionsHandler;
-  std::unique_ptr<PragmaHandler> PackHandler;
-  std::unique_ptr<PragmaHandler> MSStructHandler;
-  std::unique_ptr<PragmaHandler> UnusedHandler;
-  std::unique_ptr<PragmaHandler> WeakHandler;
-  std::unique_ptr<PragmaHandler> RedefineExtnameHandler;
-  std::unique_ptr<PragmaHandler> FPContractHandler;
-  std::unique_ptr<PragmaHandler> OpenCLExtensionHandler;
-  std::unique_ptr<PragmaHandler> OpenMPHandler;
-  std::unique_ptr<PragmaHandler> OpenACCHandler;
-  std::unique_ptr<PragmaHandler> PCSectionHandler;
-  std::unique_ptr<PragmaHandler> MSCommentHandler;
-  std::unique_ptr<PragmaHandler> MSDetectMismatchHandler;
-  std::unique_ptr<PragmaHandler> FPEvalMethodHandler;
-  std::unique_ptr<PragmaHandler> FloatControlHandler;
-  std::unique_ptr<PragmaHandler> MSPointersToMembers;
-  std::unique_ptr<PragmaHandler> MSVtorDisp;
-  std::unique_ptr<PragmaHandler> MSInitSeg;
-  std::unique_ptr<PragmaHandler> MSDataSeg;
-  std::unique_ptr<PragmaHandler> MSBSSSeg;
-  std::unique_ptr<PragmaHandler> MSConstSeg;
-  std::unique_ptr<PragmaHandler> MSCodeSeg;
-  std::unique_ptr<PragmaHandler> MSSection;
-  std::unique_ptr<PragmaHandler> MSStrictGuardStackCheck;
-  std::unique_ptr<PragmaHandler> MSRuntimeChecks;
-  std::unique_ptr<PragmaHandler> MSIntrinsic;
-  std::unique_ptr<PragmaHandler> MSFunction;
-  std::unique_ptr<PragmaHandler> MSOptimize;
-  std::unique_ptr<PragmaHandler> MSFenvAccess;
-  std::unique_ptr<PragmaHandler> MSAllocText;
-  std::unique_ptr<PragmaHandler> CUDAForceHostDeviceHandler;
-  std::unique_ptr<PragmaHandler> OptimizeHandler;
-  std::unique_ptr<PragmaHandler> LoopHintHandler;
-  std::unique_ptr<PragmaHandler> UnrollHintHandler;
-  std::unique_ptr<PragmaHandler> NoUnrollHintHandler;
-  std::unique_ptr<PragmaHandler> UnrollAndJamHintHandler;
-  std::unique_ptr<PragmaHandler> NoUnrollAndJamHintHandler;
-  std::unique_ptr<PragmaHandler> FPHandler;
-  std::unique_ptr<PragmaHandler> STDCFenvAccessHandler;
-  std::unique_ptr<PragmaHandler> STDCFenvRoundHandler;
-  std::unique_ptr<PragmaHandler> STDCCXLIMITHandler;
-  std::unique_ptr<PragmaHandler> STDCUnknownHandler;
-  std::unique_ptr<PragmaHandler> AttributePragmaHandler;
-  std::unique_ptr<PragmaHandler> MaxTokensHerePragmaHandler;
-  std::unique_ptr<PragmaHandler> MaxTokensTotalPragmaHandler;
-  std::unique_ptr<PragmaHandler> RISCVPragmaHandler;
+    ~ParseScope() { Exit(); }
+  };
 
-  std::unique_ptr<CommentHandler> CommentSemaHandler;
+  /// Introduces zero or more scopes for parsing. The scopes will all be exited
+  /// when the object is destroyed.
+  class MultiParseScope {
+    Parser &Self;
+    unsigned NumScopes = 0;
 
-  /// Whether the '>' token acts as an operator or not. This will be
-  /// true except when we are parsing an expression within a C++
-  /// template argument list, where the '>' closes the template
-  /// argument list.
-  bool GreaterThanIsOperator;
+    MultiParseScope(const MultiParseScope &) = delete;
 
-  /// ColonIsSacred - When this is false, we aggressively try to recover from
-  /// code like "foo : bar" as if it were a typo for "foo :: bar".  This is not
-  /// safe in case statements and a few other things.  This is managed by the
-  /// ColonProtectionRAIIObject RAII object.
-  bool ColonIsSacred;
+  public:
+    MultiParseScope(Parser &Self) : Self(Self) {}
+    void Enter(unsigned ScopeFlags) {
+      Self.EnterScope(ScopeFlags);
+      ++NumScopes;
+    }
+    void Exit() {
+      while (NumScopes) {
+        Self.ExitScope();
+        --NumScopes;
+      }
+    }
+    ~MultiParseScope() { Exit(); }
+  };
 
-  /// Parsing OpenMP directive mode.
-  bool OpenMPDirectiveParsing = false;
+  /// EnterScope - Start a new scope.
+  void EnterScope(unsigned ScopeFlags);
 
-  /// Parsing OpenACC directive mode.
-  bool OpenACCDirectiveParsing = false;
+  /// ExitScope - Pop a scope off the scope stack.
+  void ExitScope();
 
-  /// Currently parsing a situation where an OpenACC array section could be
-  /// legal, such as a 'var-list'.
-  bool AllowOpenACCArraySections = false;
+  //===--------------------------------------------------------------------===//
+  // Diagnostic Emission and Error recovery.
 
-  /// RAII object to set reset OpenACC parsing a context where Array Sections
-  /// are allowed.
-  class OpenACCArraySectionRAII {
-    Parser &P;
+  DiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID);
+  DiagnosticBuilder Diag(const Token...
[truncated]

diff --git a/clang/include/clang/Parse/Parser.h b/clang/include/clang/Parse/Parser.h
index ab6927130..2702fd299 100644
--- a/clang/include/clang/Parse/Parser.h
+++ b/clang/include/clang/Parse/Parser.h
@@ -217,7 +217,8 @@ public:
   /// [C]     translation-unit external-declaration
   /// [C++]   top-level-declaration-seq[opt]
   /// [C++20] global-module-fragment[opt] module-declaration
-  ///                 top-level-declaration-seq[opt] private-module-fragment[opt]
+  ///                 top-level-declaration-seq[opt]
+  ///                 private-module-fragment[opt]
   /// \endverbatim
   ///
   /// Note that in C, it is an error if there is no first declaration.
@@ -912,15 +913,16 @@ private:
   ///
   /// \verbatim
   ///       function-definition: [C99 6.9.1]
-  ///         decl-specs      declarator declaration-list[opt] compound-statement
+  ///         decl-specs      declarator declaration-list[opt]
+  ///         compound-statement
   /// [C90] function-definition: [C99 6.7.1] - implicit int result
-  /// [C90]   decl-specs[opt] declarator declaration-list[opt] compound-statement
+  /// [C90]   decl-specs[opt] declarator declaration-list[opt]
+  /// compound-statement
   ///
   ///       declaration: [C99 6.7]
   ///         declaration-specifiers init-declarator-list[opt] ';'
-  /// [!C99]  init-declarator-list ';'                   [TODO: warn in c99 mode]
-  /// [OMP]   threadprivate-directive
-  /// [OMP]   allocate-directive                         [TODO]
+  /// [!C99]  init-declarator-list ';'                   [TODO: warn in c99
+  /// mode] [OMP]   threadprivate-directive [OMP]   allocate-directive [TODO]
   /// \endverbatim
   ///
   DeclGroupPtrTy ParseDeclOrFunctionDefInternal(ParsedAttributes &Attrs,
@@ -939,10 +941,11 @@ private:
   ///
   /// \verbatim
   ///       function-definition: [C99 6.9.1]
-  ///         decl-specs      declarator declaration-list[opt] compound-statement
+  ///         decl-specs      declarator declaration-list[opt]
+  ///         compound-statement
   /// [C90] function-definition: [C99 6.7.1] - implicit int result
-  /// [C90]   decl-specs[opt] declarator declaration-list[opt] compound-statement
-  /// [C++] function-definition: [C++ 8.4]
+  /// [C90]   decl-specs[opt] declarator declaration-list[opt]
+  /// compound-statement [C++] function-definition: [C++ 8.4]
   ///         decl-specifier-seq[opt] declarator ctor-initializer[opt]
   ///         function-body
   /// [C++] function-definition: [C++ 8.4]
@@ -1783,9 +1786,7 @@ private:
   /// [C++] initializer:
   /// [C++]   '=' initializer-clause
   /// [C++]   '(' expression-list ')'
-  /// [C++0x] '=' 'default'                                                [TODO]
-  /// [C++0x] '=' 'delete'
-  /// [C++0x] braced-init-list
+  /// [C++0x] '=' 'default' [TODO] [C++0x] '=' 'delete' [C++0x] braced-init-list
   /// \endverbatim
   ///
   /// According to the standard grammar, =default and =delete are function
@@ -1902,9 +1903,11 @@ private:
   ///       enum-specifier: [C99 6.7.2.2]
   ///         'enum' identifier[opt] '{' enumerator-list '}'
   ///[C99/C++]'enum' identifier[opt] '{' enumerator-list ',' '}'
-  /// [GNU]   'enum' attributes[opt] identifier[opt] '{' enumerator-list ',' [opt]
+  /// [GNU]   'enum' attributes[opt] identifier[opt] '{' enumerator-list ','
+  /// [opt]
   ///                                                 '}' attributes[opt]
-  /// [MS]    'enum' __declspec[opt] identifier[opt] '{' enumerator-list ',' [opt]
+  /// [MS]    'enum' __declspec[opt] identifier[opt] '{' enumerator-list ','
+  /// [opt]
   ///                                                 '}'
   ///         'enum' identifier
   /// [GNU]   'enum' attributes[opt] identifier
@@ -1913,8 +1916,9 @@ private:
   /// [C++11] enum-head '{' enumerator-list ','  '}'
   ///
   ///       enum-head: [C++11]
-  ///         enum-key attribute-specifier-seq[opt] identifier[opt] enum-base[opt]
-  ///         enum-key attribute-specifier-seq[opt] nested-name-specifier
+  ///         enum-key attribute-specifier-seq[opt] identifier[opt]
+  ///         enum-base[opt] enum-key attribute-specifier-seq[opt]
+  ///         nested-name-specifier
   ///             identifier enum-base[opt]
   ///
   ///       enum-key: [C++11]
@@ -2389,8 +2393,8 @@ private:
 
   /// Parse the contents of the "objc_bridge_related" attribute.
   /// \verbatim
-  /// objc_bridge_related '(' related_class ',' opt-class_method ',' opt-instance_method ')'
-  /// related_class:
+  /// objc_bridge_related '(' related_class ',' opt-class_method ','
+  /// opt-instance_method ')' related_class:
   ///     Identifier
   ///
   /// opt-class_method:
@@ -3342,8 +3346,10 @@ private:
   ///       struct-or-union-specifier: [C99 6.7.2.1]
   ///         struct-or-union identifier[opt] '{' struct-contents '}'
   ///         struct-or-union identifier
-  /// [GNU]   struct-or-union attributes[opt] identifier[opt] '{' struct-contents
-  ///                                                         '}' attributes[opt]
+  /// [GNU]   struct-or-union attributes[opt] identifier[opt] '{'
+  /// struct-contents
+  ///                                                         '}'
+  ///                                                         attributes[opt]
   /// [GNU]   struct-or-union attributes[opt] identifier
   ///       struct-or-union:
   ///         'struct'
@@ -3415,8 +3421,8 @@ private:
   ///         decl-specifier-seq[opt] member-declarator-list[opt] ';'
   ///         function-definition ';'[opt]
   /// [C++26] friend-type-declaration
-  ///         ::[opt] nested-name-specifier template[opt] unqualified-id ';'[TODO]
-  ///         using-declaration                                            [TODO]
+  ///         ::[opt] nested-name-specifier template[opt] unqualified-id
+  ///         ';'[TODO] using-declaration [TODO]
   /// [C++0x] static_assert-declaration
   ///         template-declaration
   /// [GNU]   '__extension__' member-declaration
@@ -3870,8 +3876,9 @@ private:
   /// [GNU]   '__PRETTY_FUNCTION__'
   /// [GNU]   '(' compound-statement ')'
   /// [GNU]   '__builtin_va_arg' '(' assignment-expression ',' type-name ')'
-  /// [GNU]   '__builtin_offsetof' '(' type-name ',' offsetof-member-designator')'
-  /// [GNU]   '__builtin_choose_expr' '(' assign-expr ',' assign-expr ','
+  /// [GNU]   '__builtin_offsetof' '(' type-name ','
+  /// offsetof-member-designator')' [GNU]   '__builtin_choose_expr' '('
+  /// assign-expr ',' assign-expr ','
   ///                                     assign-expr ')'
   /// [GNU]   '__builtin_FILE' '(' ')'
   /// [CLANG] '__builtin_FILE_NAME' '(' ')'
@@ -3887,21 +3894,19 @@ private:
   /// [OBJC]  '\@protocol' '(' identifier ')'
   /// [OBJC]  '\@encode' '(' type-name ')'
   /// [OBJC]  objc-string-literal
-  /// [C++]   simple-type-specifier '(' expression-list[opt] ')'      [C++ 5.2.3]
-  /// [C++11] simple-type-specifier braced-init-list                  [C++11 5.2.3]
-  /// [C++]   typename-specifier '(' expression-list[opt] ')'         [C++ 5.2.3]
-  /// [C++11] typename-specifier braced-init-list                     [C++11 5.2.3]
-  /// [C++]   'const_cast' '<' type-name '>' '(' expression ')'       [C++ 5.2p1]
-  /// [C++]   'dynamic_cast' '<' type-name '>' '(' expression ')'     [C++ 5.2p1]
-  /// [C++]   'reinterpret_cast' '<' type-name '>' '(' expression ')' [C++ 5.2p1]
-  /// [C++]   'static_cast' '<' type-name '>' '(' expression ')'      [C++ 5.2p1]
-  /// [C++]   'typeid' '(' expression ')'                             [C++ 5.2p1]
-  /// [C++]   'typeid' '(' type-id ')'                                [C++ 5.2p1]
-  /// [C++]   'this'          [C++ 9.3.2]
-  /// [G++]   unary-type-trait '(' type-id ')'
-  /// [G++]   binary-type-trait '(' type-id ',' type-id ')'           [TODO]
-  /// [EMBT]  array-type-trait '(' type-id ',' integer ')'
-  /// [clang] '^' block-literal
+  /// [C++]   simple-type-specifier '(' expression-list[opt] ')' [C++ 5.2.3]
+  /// [C++11] simple-type-specifier braced-init-list [C++11 5.2.3] [C++]
+  /// typename-specifier '(' expression-list[opt] ')'         [C++ 5.2.3]
+  /// [C++11] typename-specifier braced-init-list [C++11 5.2.3] [C++]
+  /// 'const_cast' '<' type-name '>' '(' expression ')'       [C++ 5.2p1] [C++]
+  /// 'dynamic_cast' '<' type-name '>' '(' expression ')'     [C++ 5.2p1] [C++]
+  /// 'reinterpret_cast' '<' type-name '>' '(' expression ')' [C++ 5.2p1] [C++]
+  /// 'static_cast' '<' type-name '>' '(' expression ')'      [C++ 5.2p1] [C++]
+  /// 'typeid' '(' expression ')'                             [C++ 5.2p1] [C++]
+  /// 'typeid' '(' type-id ')'                                [C++ 5.2p1] [C++]
+  /// 'this'          [C++ 9.3.2] [G++]   unary-type-trait '(' type-id ')' [G++]
+  /// binary-type-trait '(' type-id ',' type-id ')'           [TODO] [EMBT]
+  /// array-type-trait '(' type-id ',' integer ')' [clang] '^' block-literal
   ///
   ///       constant: [C99 6.4.4]
   ///         integer-constant
@@ -4066,8 +4071,9 @@ private:
   /// \verbatim
   ///       primary-expression: [C99 6.5.1]
   /// [GNU]   '__builtin_va_arg' '(' assignment-expression ',' type-name ')'
-  /// [GNU]   '__builtin_offsetof' '(' type-name ',' offsetof-member-designator')'
-  /// [GNU]   '__builtin_choose_expr' '(' assign-expr ',' assign-expr ','
+  /// [GNU]   '__builtin_offsetof' '(' type-name ','
+  /// offsetof-member-designator')' [GNU]   '__builtin_choose_expr' '('
+  /// assign-expr ',' assign-expr ','
   ///                                     assign-expr ')'
   /// [GNU]   '__builtin_types_compatible_p' '(' type-name ',' type-name ')'
   /// [GNU]   '__builtin_FILE' '(' ')'
@@ -4769,16 +4775,8 @@ private:
   /// \verbatim
   ///       simple-type-specifier:
   ///         '::'[opt] nested-name-specifier[opt] type-name
-  ///         '::'[opt] nested-name-specifier 'template' simple-template-id [TODO]
-  ///         char
-  ///         wchar_t
-  ///         bool
-  ///         short
-  ///         int
-  ///         long
-  ///         signed
-  ///         unsigned
-  ///         float
+  ///         '::'[opt] nested-name-specifier 'template' simple-template-id
+  ///         [TODO] char wchar_t bool short int long signed unsigned float
   ///         double
   ///         void
   /// [GNU]   typeof-specifier
@@ -5429,7 +5427,8 @@ private:
   ///     '<' objc-type-parameter (',' objc-type-parameter)* '>'
   ///
   ///   objc-type-parameter:
-  ///     objc-type-parameter-variance? identifier objc-type-parameter-bound[opt]
+  ///     objc-type-parameter-variance? identifier
+  ///     objc-type-parameter-bound[opt]
   ///
   ///   objc-type-parameter-bound:
   ///     ':' type-name
@@ -5700,8 +5699,8 @@ private:
   ///     objc-keyword-selector objc-keyword-decl
   ///
   ///   objc-keyword-decl:
-  ///     objc-selector ':' objc-type-name objc-keyword-attributes[opt] identifier
-  ///     objc-selector ':' objc-keyword-attributes[opt] identifier
+  ///     objc-selector ':' objc-type-name objc-keyword-attributes[opt]
+  ///     identifier objc-selector ':' objc-keyword-attributes[opt] identifier
   ///     ':' objc-type-name objc-keyword-attributes[opt] identifier
   ///     ':' objc-keyword-attributes[opt] identifier
   ///
@@ -5775,7 +5774,8 @@ private:
   /// \verbatim
   /// objc-scalar-literal : '@' scalar-literal
   ///                        ;
-  /// scalar-literal : | numeric-constant			/* any numeric constant. */
+  /// scalar-literal : | numeric-constant			/* any numeric
+  /// constant. */
   ///                    ;
   /// \endverbatim
   ExprResult ParseObjCNumericLiteral(SourceLocation AtLoc);
@@ -5919,11 +5919,13 @@ private:
   /// \verbatim
   ///  objc-try-catch-statement:
   ///    @try compound-statement objc-catch-list[opt]
-  ///    @try compound-statement objc-catch-list[opt] @finally compound-statement
+  ///    @try compound-statement objc-catch-list[opt] @finally
+  ///    compound-statement
   ///
   ///  objc-catch-list:
   ///    @catch ( parameter-declaration ) compound-statement
-  ///    objc-catch-list @catch ( catch-parameter-declaration ) compound-statement
+  ///    objc-catch-list @catch ( catch-parameter-declaration )
+  ///    compound-statement
   ///  catch-parameter-declaration:
   ///     parameter-declaration
   ///     '...' [OBJC2]
@@ -6320,7 +6322,8 @@ private:
   /// Parses an OpenMP context selector set.
   ///
   /// \verbatim
-  /// <trait-set-selector-name> '=' '{' <trait-selector> [, <trait-selector>]* '}'
+  /// <trait-set-selector-name> '=' '{' <trait-selector> [, <trait-selector>]*
+  /// '}'
   /// \endverbatim
   void parseOMPContextSelectorSet(OMPTraitSet &TISet,
                                   llvm::StringMap<SourceLocation> &SeenSets);
@@ -6425,8 +6428,8 @@ private:
   ///        annot_pragma_openmp_end
   ///
   ///       declare-mapper-directive:
-  ///         annot_pragma_openmp 'declare' 'mapper' '(' [<mapper-identifer> ':']
-  ///         <type> <var> ')' [<clause>[[,] <clause>] ... ]
+  ///         annot_pragma_openmp 'declare' 'mapper' '(' [<mapper-identifer>
+  ///         ':'] <type> <var> ')' [<clause>[[,] <clause>] ... ]
   ///         annot_pragma_openmp_end
   ///
   ///       declare-simd-directive:
@@ -6458,8 +6461,8 @@ private:
   ///       declare-reduction-directive:
   ///        annot_pragma_openmp 'declare' 'reduction'
   ///        '(' <reduction_id> ':' <type> {',' <type>} ':' <expression> ')'
-  ///        ['initializer' '(' ('omp_priv' '=' <expression>)|<function_call> ')']
-  ///        annot_pragma_openmp_end
+  ///        ['initializer' '(' ('omp_priv' '=' <expression>)|<function_call>
+  ///        ')'] annot_pragma_openmp_end
   /// \endverbatim
   /// <reduction_id> is either a base language identifier or one of the
   /// following operators: '+', '-', '*', '&', '|', '^', '&&' and '||'.
@@ -6474,8 +6477,8 @@ private:
   ///
   /// \verbatim
   ///       declare-mapper-directive:
-  ///         annot_pragma_openmp 'declare' 'mapper' '(' [<mapper-identifier> ':']
-  ///         <type> <var> ')' [<clause>[[,] <clause>] ... ]
+  ///         annot_pragma_openmp 'declare' 'mapper' '(' [<mapper-identifier>
+  ///         ':'] <type> <var> ')' [<clause>[[,] <clause>] ... ]
   ///         annot_pragma_openmp_end
   /// \endverbatim
   /// <mapper-identifier> and <var> are base language identifiers.
@@ -6523,8 +6526,8 @@ private:
   ///         annot_pragma_openmp_end
   ///
   ///       declare-mapper-directive:
-  ///         annot_pragma_openmp 'declare' 'mapper' '(' [<mapper-identifer> ':']
-  ///         <type> <var> ')' [<clause>[[,] <clause>] ... ]
+  ///         annot_pragma_openmp 'declare' 'mapper' '(' [<mapper-identifer>
+  ///         ':'] <type> <var> ')' [<clause>[[,] <clause>] ... ]
   ///         annot_pragma_openmp_end
   ///
   ///       executable-directive:
@@ -6697,7 +6700,8 @@ private:
   ///
   /// \verbatim
   ///    schedule-clause:
-  ///      'schedule' '(' [ modifier [ ',' modifier ] ':' ] kind [',' expression ]
+  ///      'schedule' '(' [ modifier [ ',' modifier ] ':' ] kind [',' expression
+  ///      ]
   ///      ')'
   ///
   ///    if-clause:
@@ -6869,7 +6873,8 @@ private:
   ///
   /// \verbatim
   /// init-clause:
-  ///   init([interop-modifier, ]interop-type[[, interop-type] ... ]:interop-var)
+  ///   init([interop-modifier, ]interop-type[[, interop-type] ...
+  ///   ]:interop-var)
   ///
   /// destroy-clause:
   ///   destroy(interop-var)
@@ -6923,10 +6928,10 @@ public:
   bool parseMapperModifier(SemaOpenMP::OpenMPVarListDataTy &Data);
 
   /// Parse map-type-modifiers in map clause.
-  /// map([ [map-type-modifier[,] [map-type-modifier[,] ...] [map-type] : ] list)
-  /// where, map-type-modifier ::= always | close | mapper(mapper-identifier) |
-  /// present
-  /// where, map-type ::= alloc | delete | from | release | to | tofrom
+  /// map([ [map-type-modifier[,] [map-type-modifier[,] ...] [map-type] : ]
+  /// list) where, map-type-modifier ::= always | close |
+  /// mapper(mapper-identifier) | present where, map-type ::= alloc | delete |
+  /// from | release | to | tofrom
   bool parseMapTypeModifiers(SemaOpenMP::OpenMPVarListDataTy &Data);
 
   ///@}
@@ -7127,8 +7132,7 @@ public:
   /// MisleadingIndentationChecker on an else active, this location is invalid.
   SourceLocation MisleadingIndentationElseLoc;
 
-  private:
-
+private:
   /// Flags describing a context in which we're parsing a statement.
   enum class ParsedStmtContext {
     /// This context permits declarations in language modes where declarations
@@ -7367,9 +7371,8 @@ public:
   ///       for-statement: [C99 6.8.5.3]
   ///         'for' '(' expr[opt] ';' expr[opt] ';' expr[opt] ')' statement
   ///         'for' '(' declaration expr[opt] ';' expr[opt] ')' statement
-  /// [C++]   'for' '(' for-init-statement condition[opt] ';' expression[opt] ')'
-  /// [C++]       statement
-  /// [C++0x] 'for'
+  /// [C++]   'for' '(' for-init-statement condition[opt] ';' expression[opt]
+  /// ')' [C++]       statement [C++0x] 'for'
   ///             'co_await'[opt]    [Coroutines]
   ///             '(' for-range-declaration ':' for-range-initializer ')'
   ///             statement
@@ -7477,7 +7480,8 @@ public:
   ///
   ///   exception-declaration:
   ///     attribute-specifier-seq[opt] type-specifier-seq declarator
-  ///     attribute-specifier-seq[opt] type-specifier-seq abstract-declarator[opt]
+  ///     attribute-specifier-seq[opt] type-specifier-seq
+  ///     abstract-declarator[opt]
   ///     '...'
   /// \endverbatim
   ///
@@ -7602,7 +7606,7 @@ private:
   /// [GNU] asm-clobbers:
   ///         asm-string-literal
   ///         asm-clobbers ',' asm-string-literal
-  /// \endverbatim 
+  /// \endverbatim
   ///
   StmtResult ParseAsmStatement(bool &msAsm);
 
@@ -7948,7 +7952,8 @@ private:
   ///
   /// \verbatim
   ///       template-declaration: [C++ temp]
-  ///         'export'[opt] 'template' '<' template-parameter-list '>' declaration
+  ///         'export'[opt] 'template' '<' template-parameter-list '>'
+  ///         declaration
   ///
   ///       template-declaration: [C++2a]
   ///         template-head declaration
@@ -8745,7 +8750,7 @@ private:
   ///         ptr-operator:
   ///           '*' cv-qualifier-seq[opt]
   ///           '&'
-  /// [C++0x]   '&&'                                                        [TODO]
+  /// [C++0x]   '&&' [TODO]
   ///           '::'[opt] nested-name-specifier '*' cv-qualifier-seq[opt]
   ///
   ///         cv-qualifier-seq:
@@ -8760,16 +8765,15 @@ private:
   ///
   ///         id-expression:
   ///           unqualified-id
-  ///           qualified-id                                                [TODO]
+  ///           qualified-id [TODO]
   ///
   ///         unqualified-id:
   ///           identifier
   ///           operator-function-id
   ///           conversion-function-id
   ///           literal-operator-id
-  ///           '~' class-name                                              [TODO]
-  ///           '~' decltype-specifier                                      [TODO]
-  ///           template-id                                                 [TODO]
+  ///           '~' class-name [TODO]
+  ///           '~' decltype-specifier [TODO] template-id [TODO]
   /// \endverbatim
   ///
   TPResult TryParseDeclarator(bool mayBeAbstract, bool mayHaveIdentifier = true,
@@ -8786,8 +8790,9 @@ private:
   ///   parameter-declaration-list ',' parameter-declaration
   ///
   /// parameter-declaration:
-  ///   attribute-specifier-seq[opt] decl-specifier-seq declarator attributes[opt]
-  ///   attribute-specifier-seq[opt] decl-specifier-seq declarator attributes[opt]
+  ///   attribute-specifier-seq[opt] decl-specifier-seq declarator
+  ///   attributes[opt] attribute-specifier-seq[opt] decl-specifier-seq
+  ///   declarator attributes[opt]
   ///     '=' assignment-expression
   ///   attribute-specifier-seq[opt] decl-specifier-seq abstract-declarator[opt]
   ///     attributes[opt]