--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/clang/lib/Parse/ParseTentative.cpp	Thu Dec 12 13:56:28 2013 +0900
@@ -0,0 +1,1837 @@
+//===--- ParseTentative.cpp - Ambiguity Resolution Parsing ----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements the tentative parsing portions of the Parser
+//  interfaces, for ambiguity resolution.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Parse/Parser.h"
+#include "clang/Parse/ParseDiagnostic.h"
+#include "clang/Sema/ParsedTemplate.h"
+using namespace clang;
+
+/// isCXXDeclarationStatement - C++-specialized function that disambiguates
+/// between a declaration or an expression statement, when parsing function
+/// bodies. Returns true for declaration, false for expression.
+///
+///         declaration-statement:
+///           block-declaration
+///
+///         block-declaration:
+///           simple-declaration
+///           asm-definition
+///           namespace-alias-definition
+///           using-declaration
+///           using-directive
+/// [C++0x]   static_assert-declaration
+///
+///         asm-definition:
+///           'asm' '(' string-literal ')' ';'
+///
+///         namespace-alias-definition:
+///           'namespace' identifier = qualified-namespace-specifier ';'
+///
+///         using-declaration:
+///           'using' typename[opt] '::'[opt] nested-name-specifier
+///                 unqualified-id ';'
+///           'using' '::' unqualified-id ;
+///
+///         using-directive:
+///           'using' 'namespace' '::'[opt] nested-name-specifier[opt]
+///                 namespace-name ';'
+///
+bool Parser::isCXXDeclarationStatement() {
+  switch (Tok.getKind()) {
+    // asm-definition
+  case tok::kw_asm:
+    // namespace-alias-definition
+  case tok::kw_namespace:
+    // using-declaration
+    // using-directive
+  case tok::kw_using:
+    // static_assert-declaration
+  case tok::kw_static_assert:
+  case tok::kw__Static_assert:
+    return true;
+    // simple-declaration
+  default:
+    return isCXXSimpleDeclaration(/*AllowForRangeDecl=*/false);
+  }
+}
+
+/// isCXXSimpleDeclaration - C++-specialized function that disambiguates
+/// between a simple-declaration or an expression-statement.
+/// If during the disambiguation process a parsing error is encountered,
+/// the function returns true to let the declaration parsing code handle it.
+/// Returns false if the statement is disambiguated as expression.
+///
+/// simple-declaration:
+///   decl-specifier-seq init-declarator-list[opt] ';'
+///
+/// (if AllowForRangeDecl specified)
+/// for ( for-range-declaration : for-range-initializer ) statement
+/// for-range-declaration: 
+///    attribute-specifier-seqopt type-specifier-seq declarator
+bool Parser::isCXXSimpleDeclaration(bool AllowForRangeDecl) {
+  // C++ 6.8p1:
+  // There is an ambiguity in the grammar involving expression-statements and
+  // declarations: An expression-statement with a function-style explicit type
+  // conversion (5.2.3) as its leftmost subexpression can be indistinguishable
+  // from a declaration where the first declarator starts with a '('. In those
+  // cases the statement is a declaration. [Note: To disambiguate, the whole
+  // statement might have to be examined to determine if it is an
+  // expression-statement or a declaration].
+
+  // C++ 6.8p3:
+  // The disambiguation is purely syntactic; that is, the meaning of the names
+  // occurring in such a statement, beyond whether they are type-names or not,
+  // is not generally used in or changed by the disambiguation. Class
+  // templates are instantiated as necessary to determine if a qualified name
+  // is a type-name. Disambiguation precedes parsing, and a statement
+  // disambiguated as a declaration may be an ill-formed declaration.
+
+  // We don't have to parse all of the decl-specifier-seq part. There's only
+  // an ambiguity if the first decl-specifier is
+  // simple-type-specifier/typename-specifier followed by a '(', which may
+  // indicate a function-style cast expression.
+  // isCXXDeclarationSpecifier will return TPResult::Ambiguous() only in such
+  // a case.
+
+  bool InvalidAsDeclaration = false;
+  TPResult TPR = isCXXDeclarationSpecifier(TPResult::False(),
+                                           &InvalidAsDeclaration);
+  if (TPR != TPResult::Ambiguous())
+    return TPR != TPResult::False(); // Returns true for TPResult::True() or
+                                     // TPResult::Error().
+
+  // FIXME: TryParseSimpleDeclaration doesn't look past the first initializer,
+  // and so gets some cases wrong. We can't carry on if we've already seen
+  // something which makes this statement invalid as a declaration in this case,
+  // since it can cause us to misparse valid code. Revisit this once
+  // TryParseInitDeclaratorList is fixed.
+  if (InvalidAsDeclaration)
+    return false;
+
+  // FIXME: Add statistics about the number of ambiguous statements encountered
+  // and how they were resolved (number of declarations+number of expressions).
+
+  // Ok, we have a simple-type-specifier/typename-specifier followed by a '(',
+  // or an identifier which doesn't resolve as anything. We need tentative
+  // parsing...
+
+  TentativeParsingAction PA(*this);
+  TPR = TryParseSimpleDeclaration(AllowForRangeDecl);
+  PA.Revert();
+
+  // In case of an error, let the declaration parsing code handle it.
+  if (TPR == TPResult::Error())
+    return true;
+
+  // Declarations take precedence over expressions.
+  if (TPR == TPResult::Ambiguous())
+    TPR = TPResult::True();
+
+  assert(TPR == TPResult::True() || TPR == TPResult::False());
+  return TPR == TPResult::True();
+}
+
+/// Try to consume a token sequence that we've already identified as
+/// (potentially) starting a decl-specifier.
+Parser::TPResult Parser::TryConsumeDeclarationSpecifier() {
+  switch (Tok.getKind()) {
+  case tok::kw__Atomic:
+    if (NextToken().isNot(tok::l_paren)) {
+      ConsumeToken();
+      break;
+    }
+    // Fall through.
+  case tok::kw_typeof:
+  case tok::kw___attribute:
+  case tok::kw___underlying_type: {
+    ConsumeToken();
+    if (Tok.isNot(tok::l_paren))
+      return TPResult::Error();
+    ConsumeParen();
+    if (!SkipUntil(tok::r_paren))
+      return TPResult::Error();
+    break;
+  }
+
+  case tok::kw_class:
+  case tok::kw_struct:
+  case tok::kw_union:
+  case tok::kw___interface:
+  case tok::kw_enum:
+    // elaborated-type-specifier:
+    //     class-key attribute-specifier-seq[opt]
+    //         nested-name-specifier[opt] identifier
+    //     class-key nested-name-specifier[opt] template[opt] simple-template-id
+    //     enum nested-name-specifier[opt] identifier
+    //
+    // FIXME: We don't support class-specifiers nor enum-specifiers here.
+    ConsumeToken();
+
+    // Skip attributes.
+    while (Tok.is(tok::l_square) || Tok.is(tok::kw___attribute) ||
+           Tok.is(tok::kw___declspec) || Tok.is(tok::kw_alignas)) {
+      if (Tok.is(tok::l_square)) {
+        ConsumeBracket();
+        if (!SkipUntil(tok::r_square))
+          return TPResult::Error();
+      } else {
+        ConsumeToken();
+        if (Tok.isNot(tok::l_paren))
+          return TPResult::Error();
+        ConsumeParen();
+        if (!SkipUntil(tok::r_paren))
+          return TPResult::Error();
+      }
+    }
+
+    if (TryAnnotateCXXScopeToken())
+      return TPResult::Error();
+    if (Tok.is(tok::annot_cxxscope))
+      ConsumeToken();
+    if (Tok.isNot(tok::identifier) && Tok.isNot(tok::annot_template_id))
+      return TPResult::Error();
+    ConsumeToken();
+    break;
+
+  case tok::annot_cxxscope:
+    ConsumeToken();
+    // Fall through.
+  default:
+    ConsumeToken();
+
+    if (getLangOpts().ObjC1 && Tok.is(tok::less))
+      return TryParseProtocolQualifiers();
+    break;
+  }
+
+  return TPResult::Ambiguous();
+}
+
+/// simple-declaration:
+///   decl-specifier-seq init-declarator-list[opt] ';'
+///
+/// (if AllowForRangeDecl specified)
+/// for ( for-range-declaration : for-range-initializer ) statement
+/// for-range-declaration: 
+///    attribute-specifier-seqopt type-specifier-seq declarator
+///
+Parser::TPResult Parser::TryParseSimpleDeclaration(bool AllowForRangeDecl) {
+  if (TryConsumeDeclarationSpecifier() == TPResult::Error())
+    return TPResult::Error();
+
+  // Two decl-specifiers in a row conclusively disambiguate this as being a
+  // simple-declaration. Don't bother calling isCXXDeclarationSpecifier in the
+  // overwhelmingly common case that the next token is a '('.
+  if (Tok.isNot(tok::l_paren)) {
+    TPResult TPR = isCXXDeclarationSpecifier();
+    if (TPR == TPResult::Ambiguous())
+      return TPResult::True();
+    if (TPR == TPResult::True() || TPR == TPResult::Error())
+      return TPR;
+    assert(TPR == TPResult::False());
+  }
+
+  TPResult TPR = TryParseInitDeclaratorList();
+  if (TPR != TPResult::Ambiguous())
+    return TPR;
+
+  if (Tok.isNot(tok::semi) && (!AllowForRangeDecl || Tok.isNot(tok::colon)))
+    return TPResult::False();
+
+  return TPResult::Ambiguous();
+}
+
+/// Tentatively parse an init-declarator-list in order to disambiguate it from
+/// an expression.
+///
+///       init-declarator-list:
+///         init-declarator
+///         init-declarator-list ',' init-declarator
+///
+///       init-declarator:
+///         declarator initializer[opt]
+/// [GNU]   declarator simple-asm-expr[opt] attributes[opt] initializer[opt]
+///
+///       initializer:
+///         brace-or-equal-initializer
+///         '(' expression-list ')'
+///
+///       brace-or-equal-initializer:
+///         '=' initializer-clause
+/// [C++11] braced-init-list
+///
+///       initializer-clause:
+///         assignment-expression
+///         braced-init-list
+///
+///       braced-init-list:
+///         '{' initializer-list ','[opt] '}'
+///         '{' '}'
+///
+Parser::TPResult Parser::TryParseInitDeclaratorList() {
+  while (1) {
+    // declarator
+    TPResult TPR = TryParseDeclarator(false/*mayBeAbstract*/);
+    if (TPR != TPResult::Ambiguous())
+      return TPR;
+
+    // [GNU] simple-asm-expr[opt] attributes[opt]
+    if (Tok.is(tok::kw_asm) || Tok.is(tok::kw___attribute))
+      return TPResult::True();
+
+    // initializer[opt]
+    if (Tok.is(tok::l_paren)) {
+      // Parse through the parens.
+      ConsumeParen();
+      if (!SkipUntil(tok::r_paren, StopAtSemi))
+        return TPResult::Error();
+    } else if (Tok.is(tok::l_brace)) {
+      // A left-brace here is sufficient to disambiguate the parse; an
+      // expression can never be followed directly by a braced-init-list.
+      return TPResult::True();
+    } else if (Tok.is(tok::equal) || isTokIdentifier_in()) {
+      // MSVC and g++ won't examine the rest of declarators if '=' is
+      // encountered; they just conclude that we have a declaration.
+      // EDG parses the initializer completely, which is the proper behavior
+      // for this case.
+      //
+      // At present, Clang follows MSVC and g++, since the parser does not have
+      // the ability to parse an expression fully without recording the
+      // results of that parse.
+      // FIXME: Handle this case correctly.
+      //
+      // Also allow 'in' after an Objective-C declaration as in:
+      // for (int (^b)(void) in array). Ideally this should be done in the
+      // context of parsing for-init-statement of a foreach statement only. But,
+      // in any other context 'in' is invalid after a declaration and parser
+      // issues the error regardless of outcome of this decision.
+      // FIXME: Change if above assumption does not hold.
+      return TPResult::True();
+    }
+
+    if (Tok.isNot(tok::comma))
+      break;
+    ConsumeToken(); // the comma.
+  }
+
+  return TPResult::Ambiguous();
+}
+
+/// isCXXConditionDeclaration - Disambiguates between a declaration or an
+/// expression for a condition of a if/switch/while/for statement.
+/// If during the disambiguation process a parsing error is encountered,
+/// the function returns true to let the declaration parsing code handle it.
+///
+///       condition:
+///         expression
+///         type-specifier-seq declarator '=' assignment-expression
+/// [C++11] type-specifier-seq declarator '=' initializer-clause
+/// [C++11] type-specifier-seq declarator braced-init-list
+/// [GNU]   type-specifier-seq declarator simple-asm-expr[opt] attributes[opt]
+///             '=' assignment-expression
+///
+bool Parser::isCXXConditionDeclaration() {
+  TPResult TPR = isCXXDeclarationSpecifier();
+  if (TPR != TPResult::Ambiguous())
+    return TPR != TPResult::False(); // Returns true for TPResult::True() or
+                                     // TPResult::Error().
+
+  // FIXME: Add statistics about the number of ambiguous statements encountered
+  // and how they were resolved (number of declarations+number of expressions).
+
+  // Ok, we have a simple-type-specifier/typename-specifier followed by a '('.
+  // We need tentative parsing...
+
+  TentativeParsingAction PA(*this);
+
+  // type-specifier-seq
+  TryConsumeDeclarationSpecifier();
+  assert(Tok.is(tok::l_paren) && "Expected '('");
+
+  // declarator
+  TPR = TryParseDeclarator(false/*mayBeAbstract*/);
+
+  // In case of an error, let the declaration parsing code handle it.
+  if (TPR == TPResult::Error())
+    TPR = TPResult::True();
+
+  if (TPR == TPResult::Ambiguous()) {
+    // '='
+    // [GNU] simple-asm-expr[opt] attributes[opt]
+    if (Tok.is(tok::equal)  ||
+        Tok.is(tok::kw_asm) || Tok.is(tok::kw___attribute))
+      TPR = TPResult::True();
+    else if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace))
+      TPR = TPResult::True();
+    else
+      TPR = TPResult::False();
+  }
+
+  PA.Revert();
+
+  assert(TPR == TPResult::True() || TPR == TPResult::False());
+  return TPR == TPResult::True();
+}
+
+  /// \brief Determine whether the next set of tokens contains a type-id.
+  ///
+  /// The context parameter states what context we're parsing right
+  /// now, which affects how this routine copes with the token
+  /// following the type-id. If the context is TypeIdInParens, we have
+  /// already parsed the '(' and we will cease lookahead when we hit
+  /// the corresponding ')'. If the context is
+  /// TypeIdAsTemplateArgument, we've already parsed the '<' or ','
+  /// before this template argument, and will cease lookahead when we
+  /// hit a '>', '>>' (in C++0x), or ','. Returns true for a type-id
+  /// and false for an expression.  If during the disambiguation
+  /// process a parsing error is encountered, the function returns
+  /// true to let the declaration parsing code handle it.
+  ///
+  /// type-id:
+  ///   type-specifier-seq abstract-declarator[opt]
+  ///
+bool Parser::isCXXTypeId(TentativeCXXTypeIdContext Context, bool &isAmbiguous) {
+
+  isAmbiguous = false;
+
+  // C++ 8.2p2:
+  // The ambiguity arising from the similarity between a function-style cast and
+  // a type-id can occur in different contexts. The ambiguity appears as a
+  // choice between a function-style cast expression and a declaration of a
+  // type. The resolution is that any construct that could possibly be a type-id
+  // in its syntactic context shall be considered a type-id.
+
+  TPResult TPR = isCXXDeclarationSpecifier();
+  if (TPR != TPResult::Ambiguous())
+    return TPR != TPResult::False(); // Returns true for TPResult::True() or
+                                     // TPResult::Error().
+
+  // FIXME: Add statistics about the number of ambiguous statements encountered
+  // and how they were resolved (number of declarations+number of expressions).
+
+  // Ok, we have a simple-type-specifier/typename-specifier followed by a '('.
+  // We need tentative parsing...
+
+  TentativeParsingAction PA(*this);
+
+  // type-specifier-seq
+  TryConsumeDeclarationSpecifier();
+  assert(Tok.is(tok::l_paren) && "Expected '('");
+
+  // declarator
+  TPR = TryParseDeclarator(true/*mayBeAbstract*/, false/*mayHaveIdentifier*/);
+
+  // In case of an error, let the declaration parsing code handle it.
+  if (TPR == TPResult::Error())
+    TPR = TPResult::True();
+
+  if (TPR == TPResult::Ambiguous()) {
+    // We are supposed to be inside parens, so if after the abstract declarator
+    // we encounter a ')' this is a type-id, otherwise it's an expression.
+    if (Context == TypeIdInParens && Tok.is(tok::r_paren)) {
+      TPR = TPResult::True();
+      isAmbiguous = true;
+
+    // We are supposed to be inside a template argument, so if after
+    // the abstract declarator we encounter a '>', '>>' (in C++0x), or
+    // ',', this is a type-id. Otherwise, it's an expression.
+    } else if (Context == TypeIdAsTemplateArgument &&
+               (Tok.is(tok::greater) || Tok.is(tok::comma) ||
+                (getLangOpts().CPlusPlus11 && Tok.is(tok::greatergreater)))) {
+      TPR = TPResult::True();
+      isAmbiguous = true;
+
+    } else
+      TPR = TPResult::False();
+  }
+
+  PA.Revert();
+
+  assert(TPR == TPResult::True() || TPR == TPResult::False());
+  return TPR == TPResult::True();
+}
+
+/// \brief Returns true if this is a C++11 attribute-specifier. Per
+/// C++11 [dcl.attr.grammar]p6, two consecutive left square bracket tokens
+/// always introduce an attribute. In Objective-C++11, this rule does not
+/// apply if either '[' begins a message-send.
+///
+/// If Disambiguate is true, we try harder to determine whether a '[[' starts
+/// an attribute-specifier, and return CAK_InvalidAttributeSpecifier if not.
+///
+/// If OuterMightBeMessageSend is true, we assume the outer '[' is either an
+/// Obj-C message send or the start of an attribute. Otherwise, we assume it
+/// is not an Obj-C message send.
+///
+/// C++11 [dcl.attr.grammar]:
+///
+///     attribute-specifier:
+///         '[' '[' attribute-list ']' ']'
+///         alignment-specifier
+///
+///     attribute-list:
+///         attribute[opt]
+///         attribute-list ',' attribute[opt]
+///         attribute '...'
+///         attribute-list ',' attribute '...'
+///
+///     attribute:
+///         attribute-token attribute-argument-clause[opt]
+///
+///     attribute-token:
+///         identifier
+///         identifier '::' identifier
+///
+///     attribute-argument-clause:
+///         '(' balanced-token-seq ')'
+Parser::CXX11AttributeKind
+Parser::isCXX11AttributeSpecifier(bool Disambiguate,
+                                  bool OuterMightBeMessageSend) {
+  if (Tok.is(tok::kw_alignas))
+    return CAK_AttributeSpecifier;
+
+  if (Tok.isNot(tok::l_square) || NextToken().isNot(tok::l_square))
+    return CAK_NotAttributeSpecifier;
+
+  // No tentative parsing if we don't need to look for ']]' or a lambda.
+  if (!Disambiguate && !getLangOpts().ObjC1)
+    return CAK_AttributeSpecifier;
+
+  TentativeParsingAction PA(*this);
+
+  // Opening brackets were checked for above.
+  ConsumeBracket();
+
+  // Outside Obj-C++11, treat anything with a matching ']]' as an attribute.
+  if (!getLangOpts().ObjC1) {
+    ConsumeBracket();
+
+    bool IsAttribute = SkipUntil(tok::r_square);
+    IsAttribute &= Tok.is(tok::r_square);
+
+    PA.Revert();
+
+    return IsAttribute ? CAK_AttributeSpecifier : CAK_InvalidAttributeSpecifier;
+  }
+
+  // In Obj-C++11, we need to distinguish four situations:
+  //  1a) int x[[attr]];                     C++11 attribute.
+  //  1b) [[attr]];                          C++11 statement attribute.
+  //   2) int x[[obj](){ return 1; }()];     Lambda in array size/index.
+  //  3a) int x[[obj get]];                  Message send in array size/index.
+  //  3b) [[Class alloc] init];              Message send in message send.
+  //   4) [[obj]{ return self; }() doStuff]; Lambda in message send.
+  // (1) is an attribute, (2) is ill-formed, and (3) and (4) are accepted.
+
+  // If we have a lambda-introducer, then this is definitely not a message send.
+  // FIXME: If this disambiguation is too slow, fold the tentative lambda parse
+  // into the tentative attribute parse below.
+  LambdaIntroducer Intro;
+  if (!TryParseLambdaIntroducer(Intro)) {
+    // A lambda cannot end with ']]', and an attribute must.
+    bool IsAttribute = Tok.is(tok::r_square);
+
+    PA.Revert();
+
+    if (IsAttribute)
+      // Case 1: C++11 attribute.
+      return CAK_AttributeSpecifier;
+
+    if (OuterMightBeMessageSend)
+      // Case 4: Lambda in message send.
+      return CAK_NotAttributeSpecifier;
+
+    // Case 2: Lambda in array size / index.
+    return CAK_InvalidAttributeSpecifier;
+  }
+
+  ConsumeBracket();
+
+  // If we don't have a lambda-introducer, then we have an attribute or a
+  // message-send.
+  bool IsAttribute = true;
+  while (Tok.isNot(tok::r_square)) {
+    if (Tok.is(tok::comma)) {
+      // Case 1: Stray commas can only occur in attributes.
+      PA.Revert();
+      return CAK_AttributeSpecifier;
+    }
+
+    // Parse the attribute-token, if present.
+    // C++11 [dcl.attr.grammar]:
+    //   If a keyword or an alternative token that satisfies the syntactic
+    //   requirements of an identifier is contained in an attribute-token,
+    //   it is considered an identifier.
+    SourceLocation Loc;
+    if (!TryParseCXX11AttributeIdentifier(Loc)) {
+      IsAttribute = false;
+      break;
+    }
+    if (Tok.is(tok::coloncolon)) {
+      ConsumeToken();
+      if (!TryParseCXX11AttributeIdentifier(Loc)) {
+        IsAttribute = false;
+        break;
+      }
+    }
+
+    // Parse the attribute-argument-clause, if present.
+    if (Tok.is(tok::l_paren)) {
+      ConsumeParen();
+      if (!SkipUntil(tok::r_paren)) {
+        IsAttribute = false;
+        break;
+      }
+    }
+
+    if (Tok.is(tok::ellipsis))
+      ConsumeToken();
+
+    if (Tok.isNot(tok::comma))
+      break;
+
+    ConsumeToken();
+  }
+
+  // An attribute must end ']]'.
+  if (IsAttribute) {
+    if (Tok.is(tok::r_square)) {
+      ConsumeBracket();
+      IsAttribute = Tok.is(tok::r_square);
+    } else {
+      IsAttribute = false;
+    }
+  }
+
+  PA.Revert();
+
+  if (IsAttribute)
+    // Case 1: C++11 statement attribute.
+    return CAK_AttributeSpecifier;
+
+  // Case 3: Message send.
+  return CAK_NotAttributeSpecifier;
+}
+
+Parser::TPResult Parser::TryParsePtrOperatorSeq() {
+  while (true) {
+    if (Tok.is(tok::coloncolon) || Tok.is(tok::identifier))
+      if (TryAnnotateCXXScopeToken(true))
+        return TPResult::Error();
+
+    if (Tok.is(tok::star) || Tok.is(tok::amp) || Tok.is(tok::caret) ||
+        Tok.is(tok::ampamp) ||
+        (Tok.is(tok::annot_cxxscope) && NextToken().is(tok::star))) {
+      // ptr-operator
+      ConsumeToken();
+      while (Tok.is(tok::kw_const)    ||
+             Tok.is(tok::kw_volatile) ||
+             Tok.is(tok::kw_restrict))
+        ConsumeToken();
+    } else {
+      return TPResult::True();
+    }
+  }
+}
+
+///         operator-function-id:
+///           'operator' operator
+///
+///         operator: one of
+///           new  delete  new[]  delete[]  +  -  *  /  %  ^  [...]
+///
+///         conversion-function-id:
+///           'operator' conversion-type-id
+///
+///         conversion-type-id:
+///           type-specifier-seq conversion-declarator[opt]
+///
+///         conversion-declarator:
+///           ptr-operator conversion-declarator[opt]
+///
+///         literal-operator-id:
+///           'operator' string-literal identifier
+///           'operator' user-defined-string-literal
+Parser::TPResult Parser::TryParseOperatorId() {
+  assert(Tok.is(tok::kw_operator));
+  ConsumeToken();
+
+  // Maybe this is an operator-function-id.
+  switch (Tok.getKind()) {
+  case tok::kw_new: case tok::kw_delete:
+    ConsumeToken();
+    if (Tok.is(tok::l_square) && NextToken().is(tok::r_square)) {
+      ConsumeBracket();
+      ConsumeBracket();
+    }
+    return TPResult::True();
+
+#define OVERLOADED_OPERATOR(Name, Spelling, Token, Unary, Binary, MemOnly) \
+  case tok::Token:
+#define OVERLOADED_OPERATOR_MULTI(Name, Spelling, Unary, Binary, MemOnly)
+#include "clang/Basic/OperatorKinds.def"
+    ConsumeToken();
+    return TPResult::True();
+
+  case tok::l_square:
+    if (NextToken().is(tok::r_square)) {
+      ConsumeBracket();
+      ConsumeBracket();
+      return TPResult::True();
+    }
+    break;
+
+  case tok::l_paren:
+    if (NextToken().is(tok::r_paren)) {
+      ConsumeParen();
+      ConsumeParen();
+      return TPResult::True();
+    }
+    break;
+
+  default:
+    break;
+  }
+
+  // Maybe this is a literal-operator-id.
+  if (getLangOpts().CPlusPlus11 && isTokenStringLiteral()) {
+    bool FoundUDSuffix = false;
+    do {
+      FoundUDSuffix |= Tok.hasUDSuffix();
+      ConsumeStringToken();
+    } while (isTokenStringLiteral());
+
+    if (!FoundUDSuffix) {
+      if (Tok.is(tok::identifier))
+        ConsumeToken();
+      else
+        return TPResult::Error();
+    }
+    return TPResult::True();
+  }
+
+  // Maybe this is a conversion-function-id.
+  bool AnyDeclSpecifiers = false;
+  while (true) {
+    TPResult TPR = isCXXDeclarationSpecifier();
+    if (TPR == TPResult::Error())
+      return TPR;
+    if (TPR == TPResult::False()) {
+      if (!AnyDeclSpecifiers)
+        return TPResult::Error();
+      break;
+    }
+    if (TryConsumeDeclarationSpecifier() == TPResult::Error())
+      return TPResult::Error();
+    AnyDeclSpecifiers = true;
+  }
+  return TryParsePtrOperatorSeq();
+}
+
+///         declarator:
+///           direct-declarator
+///           ptr-operator declarator
+///
+///         direct-declarator:
+///           declarator-id
+///           direct-declarator '(' parameter-declaration-clause ')'
+///                 cv-qualifier-seq[opt] exception-specification[opt]
+///           direct-declarator '[' constant-expression[opt] ']'
+///           '(' declarator ')'
+/// [GNU]     '(' attributes declarator ')'
+///
+///         abstract-declarator:
+///           ptr-operator abstract-declarator[opt]
+///           direct-abstract-declarator
+///           ...
+///
+///         direct-abstract-declarator:
+///           direct-abstract-declarator[opt]
+///           '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
+///                 exception-specification[opt]
+///           direct-abstract-declarator[opt] '[' constant-expression[opt] ']'
+///           '(' abstract-declarator ')'
+///
+///         ptr-operator:
+///           '*' cv-qualifier-seq[opt]
+///           '&'
+/// [C++0x]   '&&'                                                        [TODO]
+///           '::'[opt] nested-name-specifier '*' cv-qualifier-seq[opt]
+///
+///         cv-qualifier-seq:
+///           cv-qualifier cv-qualifier-seq[opt]
+///
+///         cv-qualifier:
+///           'const'
+///           'volatile'
+///
+///         declarator-id:
+///           '...'[opt] id-expression
+///
+///         id-expression:
+///           unqualified-id
+///           qualified-id                                                [TODO]
+///
+///         unqualified-id:
+///           identifier
+///           operator-function-id
+///           conversion-function-id
+///           literal-operator-id
+///           '~' class-name                                              [TODO]
+///           '~' decltype-specifier                                      [TODO]
+///           template-id                                                 [TODO]
+///
+Parser::TPResult Parser::TryParseDeclarator(bool mayBeAbstract,
+                                            bool mayHaveIdentifier) {
+  // declarator:
+  //   direct-declarator
+  //   ptr-operator declarator
+  if (TryParsePtrOperatorSeq() == TPResult::Error())
+    return TPResult::Error();
+
+  // direct-declarator:
+  // direct-abstract-declarator:
+  if (Tok.is(tok::ellipsis))
+    ConsumeToken();
+
+  if ((Tok.is(tok::identifier) || Tok.is(tok::kw_operator) ||
+       (Tok.is(tok::annot_cxxscope) && (NextToken().is(tok::identifier) ||
+                                        NextToken().is(tok::kw_operator)))) &&
+      mayHaveIdentifier) {
+    // declarator-id
+    if (Tok.is(tok::annot_cxxscope))
+      ConsumeToken();
+    else if (Tok.is(tok::identifier))
+      TentativelyDeclaredIdentifiers.push_back(Tok.getIdentifierInfo());
+    if (Tok.is(tok::kw_operator)) {
+      if (TryParseOperatorId() == TPResult::Error())
+        return TPResult::Error();
+    } else
+      ConsumeToken();
+  } else if (Tok.is(tok::l_paren)) {
+    ConsumeParen();
+    if (mayBeAbstract &&
+        (Tok.is(tok::r_paren) ||       // 'int()' is a function.
+         // 'int(...)' is a function.
+         (Tok.is(tok::ellipsis) && NextToken().is(tok::r_paren)) ||
+         isDeclarationSpecifier())) {   // 'int(int)' is a function.
+      // '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
+      //        exception-specification[opt]
+      TPResult TPR = TryParseFunctionDeclarator();
+      if (TPR != TPResult::Ambiguous())
+        return TPR;
+    } else {
+      // '(' declarator ')'
+      // '(' attributes declarator ')'
+      // '(' abstract-declarator ')'
+      if (Tok.is(tok::kw___attribute) ||
+          Tok.is(tok::kw___declspec) ||
+          Tok.is(tok::kw___cdecl) ||
+          Tok.is(tok::kw___stdcall) ||
+          Tok.is(tok::kw___fastcall) ||
+          Tok.is(tok::kw___thiscall) ||
+          Tok.is(tok::kw___unaligned))
+        return TPResult::True(); // attributes indicate declaration
+      TPResult TPR = TryParseDeclarator(mayBeAbstract, mayHaveIdentifier);
+      if (TPR != TPResult::Ambiguous())
+        return TPR;
+      if (Tok.isNot(tok::r_paren))
+        return TPResult::False();
+      ConsumeParen();
+    }
+  } else if (!mayBeAbstract) {
+    return TPResult::False();
+  }
+
+  while (1) {
+    TPResult TPR(TPResult::Ambiguous());
+
+    // abstract-declarator: ...
+    if (Tok.is(tok::ellipsis))
+      ConsumeToken();
+
+    if (Tok.is(tok::l_paren)) {
+      // Check whether we have a function declarator or a possible ctor-style
+      // initializer that follows the declarator. Note that ctor-style
+      // initializers are not possible in contexts where abstract declarators
+      // are allowed.
+      if (!mayBeAbstract && !isCXXFunctionDeclarator())
+        break;
+
+      // direct-declarator '(' parameter-declaration-clause ')'
+      //        cv-qualifier-seq[opt] exception-specification[opt]
+      ConsumeParen();
+      TPR = TryParseFunctionDeclarator();
+    } else if (Tok.is(tok::l_square)) {
+      // direct-declarator '[' constant-expression[opt] ']'
+      // direct-abstract-declarator[opt] '[' constant-expression[opt] ']'
+      TPR = TryParseBracketDeclarator();
+    } else {
+      break;
+    }
+
+    if (TPR != TPResult::Ambiguous())
+      return TPR;
+  }
+
+  return TPResult::Ambiguous();
+}
+
+Parser::TPResult 
+Parser::isExpressionOrTypeSpecifierSimple(tok::TokenKind Kind) {
+  switch (Kind) {
+  // Obviously starts an expression.
+  case tok::numeric_constant:
+  case tok::char_constant:
+  case tok::wide_char_constant:
+  case tok::utf16_char_constant:
+  case tok::utf32_char_constant:
+  case tok::string_literal:
+  case tok::wide_string_literal:
+  case tok::utf8_string_literal:
+  case tok::utf16_string_literal:
+  case tok::utf32_string_literal:
+  case tok::l_square:
+  case tok::l_paren:
+  case tok::amp:
+  case tok::ampamp:
+  case tok::star:
+  case tok::plus:
+  case tok::plusplus:
+  case tok::minus:
+  case tok::minusminus:
+  case tok::tilde:
+  case tok::exclaim:
+  case tok::kw_sizeof:
+  case tok::kw___func__:
+  case tok::kw_const_cast:
+  case tok::kw_delete:
+  case tok::kw_dynamic_cast:
+  case tok::kw_false:
+  case tok::kw_new:
+  case tok::kw_operator:
+  case tok::kw_reinterpret_cast:
+  case tok::kw_static_cast:
+  case tok::kw_this:
+  case tok::kw_throw:
+  case tok::kw_true:
+  case tok::kw_typeid:
+  case tok::kw_alignof:
+  case tok::kw_noexcept:
+  case tok::kw_nullptr:
+  case tok::kw__Alignof:
+  case tok::kw___null:
+  case tok::kw___alignof:
+  case tok::kw___builtin_choose_expr:
+  case tok::kw___builtin_offsetof:
+  case tok::kw___builtin_types_compatible_p:
+  case tok::kw___builtin_va_arg:
+  case tok::kw___imag:
+  case tok::kw___real:
+  case tok::kw___FUNCTION__:
+  case tok::kw___FUNCDNAME__:
+  case tok::kw_L__FUNCTION__:
+  case tok::kw___PRETTY_FUNCTION__:
+  case tok::kw___has_nothrow_assign:
+  case tok::kw___has_nothrow_copy:
+  case tok::kw___has_nothrow_constructor:
+  case tok::kw___has_trivial_assign:
+  case tok::kw___has_trivial_copy:
+  case tok::kw___has_trivial_constructor:
+  case tok::kw___has_trivial_destructor:
+  case tok::kw___has_virtual_destructor:
+  case tok::kw___is_abstract:
+  case tok::kw___is_base_of:
+  case tok::kw___is_class:
+  case tok::kw___is_convertible_to:
+  case tok::kw___is_empty:
+  case tok::kw___is_enum:
+  case tok::kw___is_interface_class:
+  case tok::kw___is_final:
+  case tok::kw___is_literal:
+  case tok::kw___is_literal_type:
+  case tok::kw___is_pod:
+  case tok::kw___is_polymorphic:
+  case tok::kw___is_sealed:
+  case tok::kw___is_trivial:
+  case tok::kw___is_trivially_assignable:
+  case tok::kw___is_trivially_constructible:
+  case tok::kw___is_trivially_copyable:
+  case tok::kw___is_union:
+  case tok::kw___uuidof:
+    return TPResult::True();
+      
+  // Obviously starts a type-specifier-seq:
+  case tok::kw_char:
+  case tok::kw_const:
+  case tok::kw_double:
+  case tok::kw_enum:
+  case tok::kw_half:
+  case tok::kw_float:
+  case tok::kw_int:
+  case tok::kw_long:
+  case tok::kw___int64:
+  case tok::kw___int128:
+  case tok::kw_restrict:
+  case tok::kw_short:
+  case tok::kw_signed:
+  case tok::kw_struct:
+  case tok::kw_union:
+  case tok::kw_unsigned:
+  case tok::kw_void:
+  case tok::kw_volatile:
+  case tok::kw__Bool:
+  case tok::kw__Complex:
+  case tok::kw_class:
+  case tok::kw_typename:
+  case tok::kw_wchar_t:
+  case tok::kw_char16_t:
+  case tok::kw_char32_t:
+  case tok::kw__Decimal32:
+  case tok::kw__Decimal64:
+  case tok::kw__Decimal128:
+  case tok::kw___interface:
+  case tok::kw___thread:
+  case tok::kw_thread_local:
+  case tok::kw__Thread_local:
+  case tok::kw_typeof:
+  case tok::kw___underlying_type:
+  case tok::kw___cdecl:
+  case tok::kw___stdcall:
+  case tok::kw___fastcall:
+  case tok::kw___thiscall:
+  case tok::kw___unaligned:
+  case tok::kw___vector:
+  case tok::kw___pixel:
+  case tok::kw__Atomic:
+  case tok::kw_image1d_t:
+  case tok::kw_image1d_array_t:
+  case tok::kw_image1d_buffer_t:
+  case tok::kw_image2d_t:
+  case tok::kw_image2d_array_t:
+  case tok::kw_image3d_t:
+  case tok::kw_sampler_t:
+  case tok::kw_event_t:
+  case tok::kw___unknown_anytype:
+    return TPResult::False();
+
+  default:
+    break;
+  }
+  
+  return TPResult::Ambiguous();
+}
+
+bool Parser::isTentativelyDeclared(IdentifierInfo *II) {
+  return std::find(TentativelyDeclaredIdentifiers.begin(),
+                   TentativelyDeclaredIdentifiers.end(), II)
+      != TentativelyDeclaredIdentifiers.end();
+}
+
+/// isCXXDeclarationSpecifier - Returns TPResult::True() if it is a declaration
+/// specifier, TPResult::False() if it is not, TPResult::Ambiguous() if it could
+/// be either a decl-specifier or a function-style cast, and TPResult::Error()
+/// if a parsing error was found and reported.
+///
+/// If HasMissingTypename is provided, a name with a dependent scope specifier
+/// will be treated as ambiguous if the 'typename' keyword is missing. If this
+/// happens, *HasMissingTypename will be set to 'true'. This will also be used
+/// as an indicator that undeclared identifiers (which will trigger a later
+/// parse error) should be treated as types. Returns TPResult::Ambiguous() in
+/// such cases.
+///
+///         decl-specifier:
+///           storage-class-specifier
+///           type-specifier
+///           function-specifier
+///           'friend'
+///           'typedef'
+/// [C++11]   'constexpr'
+/// [GNU]     attributes declaration-specifiers[opt]
+///
+///         storage-class-specifier:
+///           'register'
+///           'static'
+///           'extern'
+///           'mutable'
+///           'auto'
+/// [GNU]     '__thread'
+/// [C++11]   'thread_local'
+/// [C11]     '_Thread_local'
+///
+///         function-specifier:
+///           'inline'
+///           'virtual'
+///           'explicit'
+///
+///         typedef-name:
+///           identifier
+///
+///         type-specifier:
+///           simple-type-specifier
+///           class-specifier
+///           enum-specifier
+///           elaborated-type-specifier
+///           typename-specifier
+///           cv-qualifier
+///
+///         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'
+///           'double'
+///           'void'
+/// [GNU]     typeof-specifier
+/// [GNU]     '_Complex'
+/// [C++11]   'auto'
+/// [C++11]   'decltype' ( expression )
+/// [C++1y]   'decltype' ( 'auto' )
+///
+///         type-name:
+///           class-name
+///           enum-name
+///           typedef-name
+///
+///         elaborated-type-specifier:
+///           class-key '::'[opt] nested-name-specifier[opt] identifier
+///           class-key '::'[opt] nested-name-specifier[opt] 'template'[opt]
+///               simple-template-id
+///           'enum' '::'[opt] nested-name-specifier[opt] identifier
+///
+///         enum-name:
+///           identifier
+///
+///         enum-specifier:
+///           'enum' identifier[opt] '{' enumerator-list[opt] '}'
+///           'enum' identifier[opt] '{' enumerator-list ',' '}'
+///
+///         class-specifier:
+///           class-head '{' member-specification[opt] '}'
+///
+///         class-head:
+///           class-key identifier[opt] base-clause[opt]
+///           class-key nested-name-specifier identifier base-clause[opt]
+///           class-key nested-name-specifier[opt] simple-template-id
+///               base-clause[opt]
+///
+///         class-key:
+///           'class'
+///           'struct'
+///           'union'
+///
+///         cv-qualifier:
+///           'const'
+///           'volatile'
+/// [GNU]     restrict
+///
+Parser::TPResult
+Parser::isCXXDeclarationSpecifier(Parser::TPResult BracedCastResult,
+                                  bool *HasMissingTypename) {
+  switch (Tok.getKind()) {
+  case tok::identifier: {
+    // Check for need to substitute AltiVec __vector keyword
+    // for "vector" identifier.
+    if (TryAltiVecVectorToken())
+      return TPResult::True();
+
+    const Token &Next = NextToken();
+    // In 'foo bar', 'foo' is always a type name outside of Objective-C.
+    if (!getLangOpts().ObjC1 && Next.is(tok::identifier))
+      return TPResult::True();
+
+    if (Next.isNot(tok::coloncolon) && Next.isNot(tok::less)) {
+      // Determine whether this is a valid expression. If not, we will hit
+      // a parse error one way or another. In that case, tell the caller that
+      // this is ambiguous. Typo-correct to type and expression keywords and
+      // to types and identifiers, in order to try to recover from errors.
+      CorrectionCandidateCallback TypoCorrection;
+      TypoCorrection.WantRemainingKeywords = false;
+      TypoCorrection.WantTypeSpecifiers = Next.isNot(tok::arrow);
+      switch (TryAnnotateName(false /* no nested name specifier */,
+                              &TypoCorrection)) {
+      case ANK_Error:
+        return TPResult::Error();
+      case ANK_TentativeDecl:
+        return TPResult::False();
+      case ANK_TemplateName:
+        // A bare type template-name which can't be a template template
+        // argument is an error, and was probably intended to be a type.
+        return GreaterThanIsOperator ? TPResult::True() : TPResult::False();
+      case ANK_Unresolved:
+        return HasMissingTypename ? TPResult::Ambiguous() : TPResult::False();
+      case ANK_Success:
+        break;
+      }
+      assert(Tok.isNot(tok::identifier) &&
+             "TryAnnotateName succeeded without producing an annotation");
+    } else {
+      // This might possibly be a type with a dependent scope specifier and
+      // a missing 'typename' keyword. Don't use TryAnnotateName in this case,
+      // since it will annotate as a primary expression, and we want to use the
+      // "missing 'typename'" logic.
+      if (TryAnnotateTypeOrScopeToken())
+        return TPResult::Error();
+      // If annotation failed, assume it's a non-type.
+      // FIXME: If this happens due to an undeclared identifier, treat it as
+      // ambiguous.
+      if (Tok.is(tok::identifier))
+        return TPResult::False();
+    }
+
+    // We annotated this token as something. Recurse to handle whatever we got.
+    return isCXXDeclarationSpecifier(BracedCastResult, HasMissingTypename);
+  }
+
+  case tok::kw_typename:  // typename T::type
+    // Annotate typenames and C++ scope specifiers.  If we get one, just
+    // recurse to handle whatever we get.
+    if (TryAnnotateTypeOrScopeToken())
+      return TPResult::Error();
+    return isCXXDeclarationSpecifier(BracedCastResult, HasMissingTypename);
+
+  case tok::coloncolon: {    // ::foo::bar
+    const Token &Next = NextToken();
+    if (Next.is(tok::kw_new) ||    // ::new
+        Next.is(tok::kw_delete))   // ::delete
+      return TPResult::False();
+  }
+    // Fall through.
+  case tok::kw_decltype:
+    // Annotate typenames and C++ scope specifiers.  If we get one, just
+    // recurse to handle whatever we get.
+    if (TryAnnotateTypeOrScopeToken())
+      return TPResult::Error();
+    return isCXXDeclarationSpecifier(BracedCastResult, HasMissingTypename);
+
+    // decl-specifier:
+    //   storage-class-specifier
+    //   type-specifier
+    //   function-specifier
+    //   'friend'
+    //   'typedef'
+    //   'constexpr'
+  case tok::kw_friend:
+  case tok::kw_typedef:
+  case tok::kw_constexpr:
+    // storage-class-specifier
+  case tok::kw_register:
+  case tok::kw_static:
+  case tok::kw_extern:
+  case tok::kw_mutable:
+  case tok::kw_auto:
+  case tok::kw___thread:
+  case tok::kw_thread_local:
+  case tok::kw__Thread_local:
+    // function-specifier
+  case tok::kw_inline:
+  case tok::kw_virtual:
+  case tok::kw_explicit:
+
+    // Modules
+  case tok::kw___module_private__:
+
+    // Debugger support
+  case tok::kw___unknown_anytype:
+      
+    // type-specifier:
+    //   simple-type-specifier
+    //   class-specifier
+    //   enum-specifier
+    //   elaborated-type-specifier
+    //   typename-specifier
+    //   cv-qualifier
+
+    // class-specifier
+    // elaborated-type-specifier
+  case tok::kw_class:
+  case tok::kw_struct:
+  case tok::kw_union:
+  case tok::kw___interface:
+    // enum-specifier
+  case tok::kw_enum:
+    // cv-qualifier
+  case tok::kw_const:
+  case tok::kw_volatile:
+
+    // GNU
+  case tok::kw_restrict:
+  case tok::kw__Complex:
+  case tok::kw___attribute:
+    return TPResult::True();
+
+    // Microsoft
+  case tok::kw___declspec:
+  case tok::kw___cdecl:
+  case tok::kw___stdcall:
+  case tok::kw___fastcall:
+  case tok::kw___thiscall:
+  case tok::kw___w64:
+  case tok::kw___sptr:
+  case tok::kw___uptr:
+  case tok::kw___ptr64:
+  case tok::kw___ptr32:
+  case tok::kw___forceinline:
+  case tok::kw___unaligned:
+    return TPResult::True();
+
+    // Borland
+  case tok::kw___pascal:
+    return TPResult::True();
+  
+    // AltiVec
+  case tok::kw___vector:
+    return TPResult::True();
+
+  case tok::annot_template_id: {
+    TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok);
+    if (TemplateId->Kind != TNK_Type_template)
+      return TPResult::False();
+    CXXScopeSpec SS;
+    AnnotateTemplateIdTokenAsType();
+    assert(Tok.is(tok::annot_typename));
+    goto case_typename;
+  }
+
+  case tok::annot_cxxscope: // foo::bar or ::foo::bar, but already parsed
+    // We've already annotated a scope; try to annotate a type.
+    if (TryAnnotateTypeOrScopeToken())
+      return TPResult::Error();
+    if (!Tok.is(tok::annot_typename)) {
+      // If the next token is an identifier or a type qualifier, then this
+      // can't possibly be a valid expression either.
+      if (Tok.is(tok::annot_cxxscope) && NextToken().is(tok::identifier)) {
+        CXXScopeSpec SS;
+        Actions.RestoreNestedNameSpecifierAnnotation(Tok.getAnnotationValue(),
+                                                     Tok.getAnnotationRange(),
+                                                     SS);
+        if (SS.getScopeRep() && SS.getScopeRep()->isDependent()) {
+          TentativeParsingAction PA(*this);
+          ConsumeToken();
+          ConsumeToken();
+          bool isIdentifier = Tok.is(tok::identifier);
+          TPResult TPR = TPResult::False();
+          if (!isIdentifier)
+            TPR = isCXXDeclarationSpecifier(BracedCastResult,
+                                            HasMissingTypename);
+          PA.Revert();
+
+          if (isIdentifier ||
+              TPR == TPResult::True() || TPR == TPResult::Error())
+            return TPResult::Error();
+
+          if (HasMissingTypename) {
+            // We can't tell whether this is a missing 'typename' or a valid
+            // expression.
+            *HasMissingTypename = true;
+            return TPResult::Ambiguous();
+          }
+        } else {
+          // Try to resolve the name. If it doesn't exist, assume it was
+          // intended to name a type and keep disambiguating.
+          switch (TryAnnotateName(false /* SS is not dependent */)) {
+          case ANK_Error:
+            return TPResult::Error();
+          case ANK_TentativeDecl:
+            return TPResult::False();
+          case ANK_TemplateName:
+            // A bare type template-name which can't be a template template
+            // argument is an error, and was probably intended to be a type.
+            return GreaterThanIsOperator ? TPResult::True() : TPResult::False();
+          case ANK_Unresolved:
+            return HasMissingTypename ? TPResult::Ambiguous()
+                                      : TPResult::False();
+          case ANK_Success:
+            // Annotated it, check again.
+            assert(Tok.isNot(tok::annot_cxxscope) ||
+                   NextToken().isNot(tok::identifier));
+            return isCXXDeclarationSpecifier(BracedCastResult,
+                                             HasMissingTypename);
+          }
+        }
+      }
+      return TPResult::False();
+    }
+    // If that succeeded, fallthrough into the generic simple-type-id case.
+
+    // The ambiguity resides in a simple-type-specifier/typename-specifier
+    // followed by a '('. The '(' could either be the start of:
+    //
+    //   direct-declarator:
+    //     '(' declarator ')'
+    //
+    //   direct-abstract-declarator:
+    //     '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
+    //              exception-specification[opt]
+    //     '(' abstract-declarator ')'
+    //
+    // or part of a function-style cast expression:
+    //
+    //     simple-type-specifier '(' expression-list[opt] ')'
+    //
+
+    // simple-type-specifier:
+
+  case tok::annot_typename:
+  case_typename:
+    // In Objective-C, we might have a protocol-qualified type.
+    if (getLangOpts().ObjC1 && NextToken().is(tok::less)) {
+      // Tentatively parse the 
+      TentativeParsingAction PA(*this);
+      ConsumeToken(); // The type token
+      
+      TPResult TPR = TryParseProtocolQualifiers();
+      bool isFollowedByParen = Tok.is(tok::l_paren);
+      bool isFollowedByBrace = Tok.is(tok::l_brace);
+      
+      PA.Revert();
+      
+      if (TPR == TPResult::Error())
+        return TPResult::Error();
+      
+      if (isFollowedByParen)
+        return TPResult::Ambiguous();
+
+      if (getLangOpts().CPlusPlus11 && isFollowedByBrace)
+        return BracedCastResult;
+      
+      return TPResult::True();
+    }
+      
+  case tok::kw_char:
+  case tok::kw_wchar_t:
+  case tok::kw_char16_t:
+  case tok::kw_char32_t:
+  case tok::kw_bool:
+  case tok::kw_short:
+  case tok::kw_int:
+  case tok::kw_long:
+  case tok::kw___int64:
+  case tok::kw___int128:
+  case tok::kw_signed:
+  case tok::kw_unsigned:
+  case tok::kw_half:
+  case tok::kw_float:
+  case tok::kw_double:
+  case tok::kw_void:
+  case tok::annot_decltype:
+    if (NextToken().is(tok::l_paren))
+      return TPResult::Ambiguous();
+
+    // This is a function-style cast in all cases we disambiguate other than
+    // one:
+    //   struct S {
+    //     enum E : int { a = 4 }; // enum
+    //     enum E : int { 4 };     // bit-field
+    //   };
+    if (getLangOpts().CPlusPlus11 && NextToken().is(tok::l_brace))
+      return BracedCastResult;
+
+    if (isStartOfObjCClassMessageMissingOpenBracket())
+      return TPResult::False();
+      
+    return TPResult::True();
+
+  // GNU typeof support.
+  case tok::kw_typeof: {
+    if (NextToken().isNot(tok::l_paren))
+      return TPResult::True();
+
+    TentativeParsingAction PA(*this);
+
+    TPResult TPR = TryParseTypeofSpecifier();
+    bool isFollowedByParen = Tok.is(tok::l_paren);
+    bool isFollowedByBrace = Tok.is(tok::l_brace);
+
+    PA.Revert();
+
+    if (TPR == TPResult::Error())
+      return TPResult::Error();
+
+    if (isFollowedByParen)
+      return TPResult::Ambiguous();
+
+    if (getLangOpts().CPlusPlus11 && isFollowedByBrace)
+      return BracedCastResult;
+
+    return TPResult::True();
+  }
+
+  // C++0x type traits support
+  case tok::kw___underlying_type:
+    return TPResult::True();
+
+  // C11 _Atomic
+  case tok::kw__Atomic:
+    return TPResult::True();
+
+  default:
+    return TPResult::False();
+  }
+}
+
+bool Parser::isCXXDeclarationSpecifierAType() {
+  switch (Tok.getKind()) {
+    // typename-specifier
+  case tok::annot_decltype:
+  case tok::annot_template_id:
+  case tok::annot_typename:
+  case tok::kw_typeof:
+  case tok::kw___underlying_type:
+    return true;
+
+    // elaborated-type-specifier
+  case tok::kw_class:
+  case tok::kw_struct:
+  case tok::kw_union:
+  case tok::kw___interface:
+  case tok::kw_enum:
+    return true;
+
+    // simple-type-specifier
+  case tok::kw_char:
+  case tok::kw_wchar_t:
+  case tok::kw_char16_t:
+  case tok::kw_char32_t:
+  case tok::kw_bool:
+  case tok::kw_short:
+  case tok::kw_int:
+  case tok::kw_long:
+  case tok::kw___int64:
+  case tok::kw___int128:
+  case tok::kw_signed:
+  case tok::kw_unsigned:
+  case tok::kw_half:
+  case tok::kw_float:
+  case tok::kw_double:
+  case tok::kw_void:
+  case tok::kw___unknown_anytype:
+    return true;
+
+  case tok::kw_auto:
+    return getLangOpts().CPlusPlus11;
+
+  case tok::kw__Atomic:
+    // "_Atomic foo"
+    return NextToken().is(tok::l_paren);
+
+  default:
+    return false;
+  }
+}
+
+/// [GNU] typeof-specifier:
+///         'typeof' '(' expressions ')'
+///         'typeof' '(' type-name ')'
+///
+Parser::TPResult Parser::TryParseTypeofSpecifier() {
+  assert(Tok.is(tok::kw_typeof) && "Expected 'typeof'!");
+  ConsumeToken();
+
+  assert(Tok.is(tok::l_paren) && "Expected '('");
+  // Parse through the parens after 'typeof'.
+  ConsumeParen();
+  if (!SkipUntil(tok::r_paren, StopAtSemi))
+    return TPResult::Error();
+
+  return TPResult::Ambiguous();
+}
+
+/// [ObjC] protocol-qualifiers:
+////         '<' identifier-list '>'
+Parser::TPResult Parser::TryParseProtocolQualifiers() {
+  assert(Tok.is(tok::less) && "Expected '<' for qualifier list");
+  ConsumeToken();
+  do {
+    if (Tok.isNot(tok::identifier))
+      return TPResult::Error();
+    ConsumeToken();
+    
+    if (Tok.is(tok::comma)) {
+      ConsumeToken();
+      continue;
+    }
+    
+    if (Tok.is(tok::greater)) {
+      ConsumeToken();
+      return TPResult::Ambiguous();
+    }
+  } while (false);
+  
+  return TPResult::Error();
+}
+
+/// isCXXFunctionDeclarator - Disambiguates between a function declarator or
+/// a constructor-style initializer, when parsing declaration statements.
+/// Returns true for function declarator and false for constructor-style
+/// initializer.
+/// If during the disambiguation process a parsing error is encountered,
+/// the function returns true to let the declaration parsing code handle it.
+///
+/// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
+///         exception-specification[opt]
+///
+bool Parser::isCXXFunctionDeclarator(bool *IsAmbiguous) {
+
+  // C++ 8.2p1:
+  // The ambiguity arising from the similarity between a function-style cast and
+  // a declaration mentioned in 6.8 can also occur in the context of a
+  // declaration. In that context, the choice is between a function declaration
+  // with a redundant set of parentheses around a parameter name and an object
+  // declaration with a function-style cast as the initializer. Just as for the
+  // ambiguities mentioned in 6.8, the resolution is to consider any construct
+  // that could possibly be a declaration a declaration.
+
+  TentativeParsingAction PA(*this);
+
+  ConsumeParen();
+  bool InvalidAsDeclaration = false;
+  TPResult TPR = TryParseParameterDeclarationClause(&InvalidAsDeclaration);
+  if (TPR == TPResult::Ambiguous()) {
+    if (Tok.isNot(tok::r_paren))
+      TPR = TPResult::False();
+    else {
+      const Token &Next = NextToken();
+      if (Next.is(tok::amp) || Next.is(tok::ampamp) ||
+          Next.is(tok::kw_const) || Next.is(tok::kw_volatile) ||
+          Next.is(tok::kw_throw) || Next.is(tok::kw_noexcept) ||
+          Next.is(tok::l_square) || isCXX11VirtSpecifier(Next) ||
+          Next.is(tok::l_brace) || Next.is(tok::kw_try) ||
+          Next.is(tok::equal) || Next.is(tok::arrow))
+        // The next token cannot appear after a constructor-style initializer,
+        // and can appear next in a function definition. This must be a function
+        // declarator.
+        TPR = TPResult::True();
+      else if (InvalidAsDeclaration)
+        // Use the absence of 'typename' as a tie-breaker.
+        TPR = TPResult::False();
+    }
+  }
+
+  PA.Revert();
+
+  if (IsAmbiguous && TPR == TPResult::Ambiguous())
+    *IsAmbiguous = true;
+
+  // In case of an error, let the declaration parsing code handle it.
+  return TPR != TPResult::False();
+}
+
+/// parameter-declaration-clause:
+///   parameter-declaration-list[opt] '...'[opt]
+///   parameter-declaration-list ',' '...'
+///
+/// parameter-declaration-list:
+///   parameter-declaration
+///   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]
+///     '=' assignment-expression
+///   attribute-specifier-seq[opt] decl-specifier-seq abstract-declarator[opt]
+///     attributes[opt]
+///   attribute-specifier-seq[opt] decl-specifier-seq abstract-declarator[opt]
+///     attributes[opt] '=' assignment-expression
+///
+Parser::TPResult
+Parser::TryParseParameterDeclarationClause(bool *InvalidAsDeclaration,
+                                           bool VersusTemplateArgument) {
+
+  if (Tok.is(tok::r_paren))
+    return TPResult::Ambiguous();
+
+  //   parameter-declaration-list[opt] '...'[opt]
+  //   parameter-declaration-list ',' '...'
+  //
+  // parameter-declaration-list:
+  //   parameter-declaration
+  //   parameter-declaration-list ',' parameter-declaration
+  //
+  while (1) {
+    // '...'[opt]
+    if (Tok.is(tok::ellipsis)) {
+      ConsumeToken();
+      if (Tok.is(tok::r_paren))
+        return TPResult::True(); // '...)' is a sign of a function declarator.
+      else
+        return TPResult::False();
+    }
+
+    // An attribute-specifier-seq here is a sign of a function declarator.
+    if (isCXX11AttributeSpecifier(/*Disambiguate*/false,
+                                  /*OuterMightBeMessageSend*/true))
+      return TPResult::True();
+
+    ParsedAttributes attrs(AttrFactory);
+    MaybeParseMicrosoftAttributes(attrs);
+
+    // decl-specifier-seq
+    // A parameter-declaration's initializer must be preceded by an '=', so
+    // decl-specifier-seq '{' is not a parameter in C++11.
+    TPResult TPR = isCXXDeclarationSpecifier(TPResult::False(),
+                                             InvalidAsDeclaration);
+
+    if (VersusTemplateArgument && TPR == TPResult::True()) {
+      // Consume the decl-specifier-seq. We have to look past it, since a
+      // type-id might appear here in a template argument.
+      bool SeenType = false;
+      do {
+        SeenType |= isCXXDeclarationSpecifierAType();
+        if (TryConsumeDeclarationSpecifier() == TPResult::Error())
+          return TPResult::Error();
+
+        // If we see a parameter name, this can't be a template argument.
+        if (SeenType && Tok.is(tok::identifier))
+          return TPResult::True();
+
+        TPR = isCXXDeclarationSpecifier(TPResult::False(),
+                                        InvalidAsDeclaration);
+        if (TPR == TPResult::Error())
+          return TPR;
+      } while (TPR != TPResult::False());
+    } else if (TPR == TPResult::Ambiguous()) {
+      // Disambiguate what follows the decl-specifier.
+      if (TryConsumeDeclarationSpecifier() == TPResult::Error())
+        return TPResult::Error();
+    } else
+      return TPR;
+
+    // declarator
+    // abstract-declarator[opt]
+    TPR = TryParseDeclarator(true/*mayBeAbstract*/);
+    if (TPR != TPResult::Ambiguous())
+      return TPR;
+
+    // [GNU] attributes[opt]
+    if (Tok.is(tok::kw___attribute))
+      return TPResult::True();
+
+    // If we're disambiguating a template argument in a default argument in
+    // a class definition versus a parameter declaration, an '=' here
+    // disambiguates the parse one way or the other.
+    // If this is a parameter, it must have a default argument because
+    //   (a) the previous parameter did, and
+    //   (b) this must be the first declaration of the function, so we can't
+    //       inherit any default arguments from elsewhere.
+    // If we see an ')', then we've reached the end of a
+    // parameter-declaration-clause, and the last param is missing its default
+    // argument.
+    if (VersusTemplateArgument)
+      return (Tok.is(tok::equal) || Tok.is(tok::r_paren)) ? TPResult::True()
+                                                          : TPResult::False();
+
+    if (Tok.is(tok::equal)) {
+      // '=' assignment-expression
+      // Parse through assignment-expression.
+      // FIXME: assignment-expression may contain an unparenthesized comma.
+      if (!SkipUntil(tok::comma, tok::r_paren, StopAtSemi | StopBeforeMatch))
+        return TPResult::Error();
+    }
+
+    if (Tok.is(tok::ellipsis)) {
+      ConsumeToken();
+      if (Tok.is(tok::r_paren))
+        return TPResult::True(); // '...)' is a sign of a function declarator.
+      else
+        return TPResult::False();
+    }
+
+    if (Tok.isNot(tok::comma))
+      break;
+    ConsumeToken(); // the comma.
+  }
+
+  return TPResult::Ambiguous();
+}
+
+/// TryParseFunctionDeclarator - We parsed a '(' and we want to try to continue
+/// parsing as a function declarator.
+/// If TryParseFunctionDeclarator fully parsed the function declarator, it will
+/// return TPResult::Ambiguous(), otherwise it will return either False() or
+/// Error().
+///
+/// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
+///         exception-specification[opt]
+///
+/// exception-specification:
+///   'throw' '(' type-id-list[opt] ')'
+///
+Parser::TPResult Parser::TryParseFunctionDeclarator() {
+
+  // The '(' is already parsed.
+
+  TPResult TPR = TryParseParameterDeclarationClause();
+  if (TPR == TPResult::Ambiguous() && Tok.isNot(tok::r_paren))
+    TPR = TPResult::False();
+
+  if (TPR == TPResult::False() || TPR == TPResult::Error())
+    return TPR;
+
+  // Parse through the parens.
+  if (!SkipUntil(tok::r_paren, StopAtSemi))
+    return TPResult::Error();
+
+  // cv-qualifier-seq
+  while (Tok.is(tok::kw_const)    ||
+         Tok.is(tok::kw_volatile) ||
+         Tok.is(tok::kw_restrict)   )
+    ConsumeToken();
+
+  // ref-qualifier[opt]
+  if (Tok.is(tok::amp) || Tok.is(tok::ampamp))
+    ConsumeToken();
+  
+  // exception-specification
+  if (Tok.is(tok::kw_throw)) {
+    ConsumeToken();
+    if (Tok.isNot(tok::l_paren))
+      return TPResult::Error();
+
+    // Parse through the parens after 'throw'.
+    ConsumeParen();
+    if (!SkipUntil(tok::r_paren, StopAtSemi))
+      return TPResult::Error();
+  }
+  if (Tok.is(tok::kw_noexcept)) {
+    ConsumeToken();
+    // Possibly an expression as well.
+    if (Tok.is(tok::l_paren)) {
+      // Find the matching rparen.
+      ConsumeParen();
+      if (!SkipUntil(tok::r_paren, StopAtSemi))
+        return TPResult::Error();
+    }
+  }
+
+  return TPResult::Ambiguous();
+}
+
+/// '[' constant-expression[opt] ']'
+///
+Parser::TPResult Parser::TryParseBracketDeclarator() {
+  ConsumeBracket();
+  if (!SkipUntil(tok::r_square, StopAtSemi))
+    return TPResult::Error();
+
+  return TPResult::Ambiguous();
+}