// Copyright (c) 2008 Roberto Raggi <roberto.raggi@gmail.com>
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#include "Parser.h"
#include "Token.h"
#include "Lexer.h"
#include "Control.h"
#include "AST.h"
#include "Literals.h"
#include "ObjectiveCTypeQualifiers.h"
#include "QtContextKeywords.h"

#include <unordered_map>
#include <utility>

#include <string>
#include <cstdio> // for putchar

#if defined(__INTEL_COMPILER) && !defined(va_copy)
#    define va_copy __va_copy
#endif

#define CPLUSPLUS_NO_DEBUG_RULE
#define MAX_EXPRESSION_DEPTH 1000
#define MAX_STATEMENT_DEPTH 300

using namespace CPlusPlus;

namespace {

class DebugRule {
public:
    static int depth;

    DebugRule(const char *name, const char *spell, int idx, bool blocked)
    {
        for (int i = 0; i <= depth; ++i)
          fputc('-', stderr);

        ++depth;
        fprintf(stderr, " %s, ahead: '%s' (%u) - block-errors: %d\n", name, spell, idx, blocked);
    }

    ~DebugRule()
    { --depth; }
};

int DebugRule::depth = 0;

inline bool lookAtAssignmentOperator(int tokenKind)
{
    switch (tokenKind) {
    case T_EQUAL:
    case T_AMPER_EQUAL:
    case T_CARET_EQUAL:
    case T_SLASH_EQUAL:
    case T_GREATER_GREATER_EQUAL:
    case T_LESS_LESS_EQUAL:
    case T_MINUS_EQUAL:
    case T_PERCENT_EQUAL:
    case T_PIPE_EQUAL:
    case T_PLUS_EQUAL:
    case T_STAR_EQUAL:
    case T_TILDE_EQUAL:
        return true;
    default:
        return false;
    } // switch
}

namespace Prec {
enum {
    Unknown         = 0,
    Comma           = 1,
    Assignment      = 2,
    Conditional     = 3,
    LogicalOr       = 4,
    LogicalAnd      = 5,
    InclusiveOr     = 6,
    ExclusiveOr     = 7,
    And             = 8,
    Equality        = 9,
    Relational      = 10,
    ThreeWayComp    = 11,
    Shift           = 12,
    Additive        = 13,
    Multiplicative  = 14,
    PointerToMember = 15
};
} // namespace Precedece

inline int precedence(int tokenKind, bool templateArguments)
{
    // ### this will/might need some tuning for C++0x
    // (see: [temp.names]p3)
    if (templateArguments && (tokenKind == T_GREATER || tokenKind == T_GREATER_GREATER))
        return -1;

    if (lookAtAssignmentOperator(tokenKind))
        return Prec::Assignment;

    switch (tokenKind) {
    case T_COMMA:               return Prec::Comma;
    case T_QUESTION:            return Prec::Conditional;
    case T_PIPE_PIPE:           return Prec::LogicalOr;
    case T_AMPER_AMPER:         return Prec::LogicalAnd;
    case T_PIPE:                return Prec::InclusiveOr;
    case T_CARET:               return Prec::ExclusiveOr;
    case T_AMPER:               return Prec::And;
    case T_EQUAL_EQUAL:
    case T_EXCLAIM_EQUAL:       return Prec::Equality;
    case T_GREATER:
    case T_LESS:
    case T_LESS_EQUAL:
    case T_GREATER_EQUAL:       return Prec::Relational;
    case T_LESS_EQUAL_GREATER:  return Prec::ThreeWayComp;
    case T_LESS_LESS:
    case T_GREATER_GREATER:     return Prec::ExclusiveOr;
    case T_PLUS:
    case T_MINUS:               return Prec::Additive;
    case T_STAR:
    case T_SLASH:
    case T_PERCENT:             return Prec::Multiplicative;
    case T_ARROW_STAR:
    case T_DOT_STAR:            return Prec::PointerToMember;
    default:                    return Prec::Unknown;
    }
}

inline bool isBinaryOperator(int tokenKind)
{ return precedence(tokenKind, false) != Prec::Unknown; }

inline bool isRightAssociative(int tokenKind)
{
    const int prec = precedence(tokenKind, false);
    return prec == Prec::Conditional || prec == Prec::Assignment;
}

} // end of anonymous namespace

class Parser::ASTCache
{
    ASTCache(const ASTCache &other);
    void operator =(const ASTCache &other);

public:
    enum ASTKind {
        Declaration,
        Expression,
        ExpressionList,
        MemberSpecification,
        ParameterDeclarationClause,
        TemplateId,
        TypeId
    };

    struct CacheKey {
        CacheKey(int initialCursor, ASTKind astKind)
            : initialCursor(initialCursor)
            , astKind(astKind)
        {}

        const int initialCursor;
        const ASTKind astKind;
    };

public:
    ASTCache() {}

    void insert(ASTKind astKind, int tokenIndexBeforeParsing,
                AST *resultingAST, int resultingTokenIndex, bool resultingReturnValue)
    {
        const auto key = std::make_pair(astKind, tokenIndexBeforeParsing);

        ParseFunctionResult result;
        result.resultingAST = resultingAST;
        result.resultingTokenIndex = resultingTokenIndex;
        result.returnValue = resultingReturnValue;
        const auto keyValue = std::make_pair(key, result);
        _cache.insert(keyValue);
    }

    AST *find(ASTKind astKind, int tokenIndex,
              int *resultingTokenIndex, bool *foundInCache, bool *returnValue) const
    {
        const auto key = std::make_pair(astKind, tokenIndex);
        const auto it = _cache.find(key);
        if (it == _cache.end()) {
            *foundInCache = false;
            return nullptr;
        } else {
            *foundInCache = true;
            *resultingTokenIndex = it->second.resultingTokenIndex;
            *returnValue = it->second.returnValue;
            return it->second.resultingAST;
        }
    }

    void clear()
    {
        _cache.clear();
    }

private:
    struct KeyHasher {
        size_t operator()(const std::pair<int, unsigned> &key) const
        { return std::hash<int>()(key.first) ^ std::hash<unsigned>()(key.second); }
    };

    struct ParseFunctionResult {
        AST *resultingAST;
        int resultingTokenIndex;
        bool returnValue;
    };

    typedef std::pair<int, int> ASTKindAndTokenIndex;
    std::unordered_map<ASTKindAndTokenIndex, ParseFunctionResult, KeyHasher> _cache;
};

#ifndef CPLUSPLUS_NO_DEBUG_RULE
#  define DEBUG_THIS_RULE() DebugRule __debug_rule__(__func__, tok().spell(), cursor(), _translationUnit->blockErrors())
inline void debugPrintCheckCache(bool goodCase)
{
    for (int i = 0; i <= DebugRule::depth - 1; ++i)
        fputc('-', stderr);
    if (goodCase)
        fprintf(stderr, " CACHE: Re-using AST from Cache.\n");
    else
        fprintf(stderr, " CACHE: Already tried to parse this, skipping.\n");
}
#else
#  define DEBUG_THIS_RULE() do {} while (0)
inline void debugPrintCheckCache(bool) {}
#endif

#define CHECK_CACHE(ASTKind, ASTType) \
    do { \
        bool foundInCache; \
        int newTokenIndex; \
        bool returnValue; \
        if (AST *ast = _astCache->find(ASTKind, cursor(), \
                                       &newTokenIndex, &foundInCache, &returnValue)) { \
            debugPrintCheckCache(true); \
            node = (ASTType *) ast; \
            _tokenIndex = newTokenIndex; \
            return returnValue; \
        } else if (foundInCache) { \
            debugPrintCheckCache(false); \
            return returnValue; \
        } \
    } while (0)

#define CACHE_AND_RETURN(cacheKey, expression) \
    do { \
        const bool result = expression; \
        _astCache->insert(cacheKey.astKind, \
                          cacheKey.initialCursor, \
                          result ? node : 0, \
                          cursor(), \
                          result); \
        return result; \
    } while (0)

#define PARSE_EXPRESSION_WITH_OPERATOR_PRECEDENCE(node, minPrecedence) { \
    if (LA() == T_THROW) { \
        if (!parseThrowExpression(node)) \
            return false; \
    } else if (!parseCastExpression(node)) \
        return false; \
    \
    parseExpressionWithOperatorPrecedence(node, minPrecedence); \
    return true; \
}

Parser::Parser(TranslationUnit *unit)
    : _translationUnit(unit),
      _control(unit->control()),
      _pool(unit->memoryPool()),
      _languageFeatures(unit->languageFeatures()),
      _tokenIndex(1),
      _templateArguments(0),
      _inFunctionBody(false),
      _inExpressionStatement(false),
      _expressionDepth(0),
      _statementDepth(0),
      _astCache(new ASTCache),
      _expressionStatementAstCache(new ASTCache)
{ }

Parser::~Parser()
{
    delete _expressionStatementAstCache;
    delete _astCache;
}

bool Parser::switchTemplateArguments(bool templateArguments)
{
    bool previousTemplateArguments = _templateArguments;
    _templateArguments = templateArguments;
    return previousTemplateArguments;
}

bool Parser::maybeSplitGreaterGreaterToken(int n)
{
    return _translationUnit->maybeSplitGreaterGreaterToken(_tokenIndex + n - 1);
}

bool Parser::skipUntil(int token)
{
    while (int tk = LA()) {
        if (tk == token)
            return true;

        consumeToken();
    }

    return false;
}

void Parser::skipUntilDeclaration()
{
    for (; ; consumeToken()) {
        switch (LA()) {
        case T_EOF_SYMBOL:

        // end of a block
        case T_RBRACE:

        // names
        case T_IDENTIFIER:
        case T_COLON_COLON:
        case T_TILDE:
        case T_OPERATOR:

        // empty declaration
        case T_SEMICOLON:

        // member specification
        case T_USING:
        case T_TEMPLATE:
        case T_PUBLIC:
        case T_PROTECTED:
        case T_PRIVATE:
        case T_Q_SIGNALS:
        case T_Q_SLOTS:
        case T_Q_PROPERTY:
        case T_Q_PRIVATE_PROPERTY:
        case T_Q_ENUMS:
        case T_Q_FLAGS:
        case T_Q_INTERFACES:

        // Qt function specifiers
        case T_Q_SIGNAL:
        case T_Q_SLOT:
        case T_Q_INVOKABLE:

        // declarations
        case T_ENUM:
        case T_NAMESPACE:
        case T_INLINE:
        case T_STATIC_ASSERT:
        case T_ASM:
        case T_EXPORT:
        case T_AT_CLASS:
        case T_AT_INTERFACE:
        case T_AT_PROTOCOL:
        case T_AT_IMPLEMENTATION:
        case T_AT_END:
            return;

        default:
            if (lookAtBuiltinTypeSpecifier() || lookAtClassKey() ||
                lookAtFunctionSpecifier() || lookAtStorageClassSpecifier())
                return;
        } // switch
    }
}

bool Parser::skipUntilStatement()
{
    while (int tk = LA()) {
        switch (tk) {
            case T_SEMICOLON:
            case T_LBRACE:
            case T_RBRACE:
            case T_CONST:
            case T_VOLATILE:
            case T_IDENTIFIER:
            case T_CASE:
            case T_DEFAULT:
            case T_IF:
            case T_SWITCH:
            case T_WHILE:
            case T_DO:
            case T_FOR:
            case T_BREAK:
            case T_CONTINUE:
            case T_RETURN:
            case T_CO_RETURN:
            case T_GOTO:
            case T_TRY:
            case T_CATCH:
            case T_THROW:
            case T_CHAR:
            case T_CHAR16_T:
            case T_CHAR32_T:
            case T_WCHAR_T:
            case T_BOOL:
            case T_SHORT:
            case T_INT:
            case T_LONG:
            case T_SIGNED:
            case T_UNSIGNED:
            case T_FLOAT:
            case T_DOUBLE:
            case T_VOID:
            case T_CLASS:
            case T_STRUCT:
            case T_UNION:
            case T_ENUM:
            case T_COLON_COLON:
            case T_TEMPLATE:
            case T_USING:
                return true;

            case T_AT_TRY:
            case T_AT_SYNCHRONIZED:
            case T_AT_THROW:
                if (_languageFeatures.objCEnabled)
                    return true;
                Q_FALLTHROUGH();
            default:
                consumeToken();
        }
    }

    return false;
}

bool Parser::skip(int l, int r)
{
    int count = 0;

    while (int tk = LA()) {
        if (tk == l)
            ++count;
        else if (tk == r)
            --count;
        else if (l != T_LBRACE && (tk == T_LBRACE ||
                                   tk == T_RBRACE ||
                                   tk == T_SEMICOLON))
            return false;

        if (count == 0)
            return true;

        consumeToken();
    }

    return false;
}

int Parser::find(int token, int stopAt)
{
    for (int i = 1; ; ++i) {
        const int tk = LA(i);
        if (!tk || tk == stopAt)
            return 0;
        if (tk == token)
            return i;
    }
    return 0;
}

void Parser::match(int kind, int *token)
{
    if (LA() == kind)
        *token = consumeToken();
    else {
        *token = 0;
        error(_tokenIndex, "expected token `%s' got `%s'",
              Token::name(kind), tok().spell());
    }
}

bool Parser::parseClassOrNamespaceName(NameAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_IDENTIFIER && (LA(2) == T_COLON_COLON || LA(2) == T_LESS)) {
        int identifier_token = cursor();

        if (LA(2) == T_LESS) {
            bool blocked = blockErrors(true);
            if (parseTemplateId(node) && LA() == T_COLON_COLON) {
                blockErrors(blocked);
                return true;
            }
            blockErrors(blocked);
        }

        rewind(identifier_token);

        if (LA(2) == T_COLON_COLON) {
            SimpleNameAST *ast = new (_pool) SimpleNameAST;
            ast->identifier_token = consumeToken();
            node = ast;
            return true;
        }
    } else if (LA() == T_TEMPLATE) {
        int template_token = consumeToken();
        if (parseTemplateId(node, template_token) && LA() == T_COLON_COLON)
            return true;
        rewind(template_token);
    }
    return false;
}

bool Parser::parseTemplateId(NameAST *&node, int template_token)
{
    DEBUG_THIS_RULE();
    CHECK_CACHE(ASTCache::TemplateId, NameAST);

    const int start = cursor();

    if (LA() == T_IDENTIFIER && LA(2) == T_LESS) {
        TemplateIdAST *ast = new (_pool) TemplateIdAST;
        ast->template_token = template_token;
        ast->identifier_token = consumeToken();
        ast->less_token = consumeToken();
        if (maybeSplitGreaterGreaterToken() || LA() == T_GREATER || parseTemplateArgumentList(
                ast->template_argument_list)) {
            if (maybeSplitGreaterGreaterToken() || LA() == T_GREATER) {
                ast->greater_token = consumeToken();
                node = ast;
                const bool result = true;
                _astCache->insert(ASTCache::TemplateId, start, node, cursor(), result);
                return result;
            }
        }
    }

    const bool result = false;
    _astCache->insert(ASTCache::TemplateId, start, nullptr, cursor(), result);
    rewind(start);
    return result;
}

bool Parser::parseNestedNameSpecifier(NestedNameSpecifierListAST *&node,
                                      bool /*acceptTemplateId*/)
{
    DEBUG_THIS_RULE();
    NestedNameSpecifierListAST **nested_name_specifier = &node;
    NameAST *class_or_namespace_name = nullptr;
    if (parseClassOrNamespaceName(class_or_namespace_name) && LA() == T_COLON_COLON) {
        int scope_token = consumeToken();

        NestedNameSpecifierAST *name = new (_pool) NestedNameSpecifierAST;
        name->class_or_namespace_name = class_or_namespace_name;
        name->scope_token = scope_token;

        *nested_name_specifier = new (_pool) NestedNameSpecifierListAST(name);
        nested_name_specifier = &(*nested_name_specifier)->next;

        while (parseClassOrNamespaceName(class_or_namespace_name) && LA() == T_COLON_COLON) {
            scope_token = consumeToken();

            name = new (_pool) NestedNameSpecifierAST;
            name->class_or_namespace_name = class_or_namespace_name;
            name->scope_token = scope_token;

            *nested_name_specifier = new (_pool) NestedNameSpecifierListAST(name);
            nested_name_specifier = &(*nested_name_specifier)->next;
        }

        // ### ugly hack
        rewind(scope_token);
        consumeToken();
        return true;
    }

    return false;
}

bool Parser::parseNestedNameSpecifierOpt(NestedNameSpecifierListAST *&name, bool acceptTemplateId)
{
    DEBUG_THIS_RULE();
    int start = cursor();
    if (! parseNestedNameSpecifier(name, acceptTemplateId))
        rewind(start);
    return true;
}

bool Parser::parseName(NameAST *&node, bool acceptTemplateId)
{
    DEBUG_THIS_RULE();
    int global_scope_token = 0;

    switch (LA()) {
    case T_COLON_COLON:
    case T_IDENTIFIER:
    case T_TILDE: // destructor-name-id
    case T_OPERATOR: // operator-name-id
    case T_TEMPLATE: // template introduced template-id
      break;
    default:
      return false;
    }

    if (LA() == T_COLON_COLON)
        global_scope_token = consumeToken();

    NestedNameSpecifierListAST *nested_name_specifier = nullptr;
    parseNestedNameSpecifierOpt(nested_name_specifier,
                                /*acceptTemplateId=*/ true);

    NameAST *unqualified_name = nullptr;
    if (parseUnqualifiedName(unqualified_name,
                             /*acceptTemplateId=*/ acceptTemplateId || nested_name_specifier != nullptr)) {
        if (! global_scope_token && ! nested_name_specifier) {
            node = unqualified_name;
            return true;
        }

        QualifiedNameAST *ast = new (_pool) QualifiedNameAST;
        ast->global_scope_token = global_scope_token;
        ast->nested_name_specifier_list = nested_name_specifier;
        ast->unqualified_name = unqualified_name;
        node = ast;
        return true;
    }

    return false;
}

bool Parser::parseTranslationUnit(TranslationUnitAST *&node)
{
    DEBUG_THIS_RULE();
    TranslationUnitAST *ast = new (_pool) TranslationUnitAST;
    DeclarationListAST **decl = &ast->declaration_list;

    while (LA()) {
        int start_declaration = cursor();

        DeclarationAST *declaration = nullptr;

        if (parseDeclaration(declaration)) {
            *decl = new (_pool) DeclarationListAST;
            (*decl)->value = declaration;
            decl = &(*decl)->next;
        } else {
            error(start_declaration, "expected a declaration");
            rewind(start_declaration + 1);
            skipUntilDeclaration();
        }


        if (TopLevelDeclarationProcessor *processor = _control->topLevelDeclarationProcessor()) {
            if (!processor->processDeclaration(declaration))
                break;
        }

        _templateArgumentList.clear();
    }

    node = ast;
    return true;
}

bool Parser::parseEmptyDeclaration(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_SEMICOLON) {
        EmptyDeclarationAST *ast = new (_pool) EmptyDeclarationAST;
        ast->semicolon_token = consumeToken();
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseDeclaration(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    switch (LA()) {
    case T_SEMICOLON:
        return parseEmptyDeclaration(node);

    case T_NAMESPACE:
        return parseNamespace(node);

    case T_USING:
        return parseUsing(node);

    case T_ASM:
        return parseAsmDefinition(node);


    case T_TEMPLATE:
    case T_EXPORT:
        return parseTemplateDeclaration(node);

    // ObjcC++
    case T_AT_CLASS:
        return parseObjCClassForwardDeclaration(node);

    case T_AT_INTERFACE:
        return parseObjCInterface(node);

    case T_AT_PROTOCOL:
        return parseObjCProtocol(node);

    case T_AT_IMPLEMENTATION:
        return parseObjCImplementation(node);

    case T_Q_DECLARE_INTERFACE:
    {
        consumeToken();
        int lparen_token = 0;
        match(T_LPAREN, &lparen_token);
        NameAST *name = nullptr;
        parseName(name);
        int comma_token = 0;
        match(T_COMMA, &comma_token);
        int string_literal = 0;
        match(T_STRING_LITERAL, &string_literal);
        int rparen_token = 0;
        match(T_RPAREN, &rparen_token);
    }   return true;

    case T_AT_END:
        // TODO: should this be done here, or higher-up?
        error(cursor(), "skip stray token `%s'", tok().spell());
        consumeToken();
        break;

    case T_INLINE:
        if (_languageFeatures.cxx11Enabled && LA(2) == T_NAMESPACE)
            return parseNamespace(node);
        return parseSimpleDeclaration(node);

    case T_STATIC_ASSERT:
        if (_languageFeatures.cxx11Enabled)
            return parseStaticAssertDeclaration(node);
        return parseSimpleDeclaration(node);

    default: {
        if (_languageFeatures.objCEnabled && LA() == T___ATTRIBUTE__) {
            const int start = cursor();
            SpecifierListAST *attributes = nullptr, **attr = &attributes;
            while (parseGnuAttributeSpecifier(*attr))
                attr = &(*attr)->next;
            if (LA() == T_AT_INTERFACE)
                return parseObjCInterface(node, attributes);
            else if (LA() == T_AT_PROTOCOL)
                return parseObjCProtocol(node, attributes);
            else if (LA() == T_AT_PROPERTY)
                return parseObjCPropertyDeclaration(node, attributes);
            rewind(start);
        } else if (LA() == T___DECLSPEC) {
            const int start = cursor();
            SpecifierListAST *attributes = nullptr, **attr = &attributes;
            while (parseMsvcDeclspecSpecifier(*attr))
                attr = &(*attr)->next;
            rewind(start);
        } else if (lookAtStdAttribute()) {
            const int start = cursor();
            SpecifierListAST *attributes = nullptr, **attr = &attributes;
            while (parseStdAttributeSpecifier(*attr))
                attr = &(*attr)->next;
            rewind(start);
        }

        if (LA() == T_EXTERN && LA(2) == T_TEMPLATE)
            return parseTemplateDeclaration(node);
        else if (LA() == T_EXTERN && LA(2) == T_STRING_LITERAL)
            return parseLinkageSpecification(node);
        else
            return parseSimpleDeclaration(node);
    }   break; // default

    } // end switch

    return false;
}

bool Parser::parseLinkageSpecification(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_EXTERN && LA(2) == T_STRING_LITERAL) {
        LinkageSpecificationAST *ast = new (_pool) LinkageSpecificationAST;
        ast->extern_token = consumeToken();
        ast->extern_type_token = consumeToken();

        if (LA() == T_LBRACE)
            parseLinkageBody(ast->declaration);
        else
            parseDeclaration(ast->declaration);

        node = ast;
        return true;
    }

    return false;
}

bool Parser::parseLinkageBody(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_LBRACE) {
        LinkageBodyAST *ast = new (_pool) LinkageBodyAST;
        ast->lbrace_token = consumeToken();
        DeclarationListAST **declaration_ptr = &ast->declaration_list;

        while (int tk = LA()) {
            if (tk == T_RBRACE)
                break;

            int start_declaration = cursor();
            DeclarationAST *declaration = nullptr;
            if (parseDeclaration(declaration)) {
                *declaration_ptr = new (_pool) DeclarationListAST;
                (*declaration_ptr)->value = declaration;
                declaration_ptr = &(*declaration_ptr)->next;
            } else {
                error(start_declaration, "expected a declaration");
                rewind(start_declaration + 1);
                skipUntilDeclaration();
            }

            _templateArgumentList.clear();
        }
        match(T_RBRACE, &ast->rbrace_token);
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseStaticAssertDeclaration(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_STATIC_ASSERT)
        return false;

    StaticAssertDeclarationAST *ast = new (_pool) StaticAssertDeclarationAST;
    ast->static_assert_token = consumeToken();
    match(T_LPAREN, &ast->lparen_token);
    parseConstantExpression(ast->expression);
    match(T_COMMA, &ast->comma_token);
    parseStringLiteral(ast->string_literal);
    match(T_RPAREN, &ast->rparen_token);
    match(T_SEMICOLON, &ast->semicolon_token);

    node = ast;
    return true;
}

// ### rename parseNamespaceAliarOrDeclaration?
bool Parser::parseNamespace(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_NAMESPACE && !(_languageFeatures.cxx11Enabled && LA() == T_INLINE && LA(2) == T_NAMESPACE)
            && !isNestedNamespace())
        return false;

    int inline_token = 0;
    if (_languageFeatures.cxx11Enabled && LA() == T_INLINE)
        inline_token = consumeToken();

    int namespace_token = consumeToken();

    if (LA() == T_IDENTIFIER && LA(2) == T_EQUAL) {
        if (inline_token)
            warning(inline_token, "namespace alias cannot be inline");
        NamespaceAliasDefinitionAST *ast =
                new (_pool) NamespaceAliasDefinitionAST;
        ast->namespace_token = namespace_token;
        ast->namespace_name_token = consumeToken();
        ast->equal_token = consumeToken();
        parseName(ast->name);
        match(T_SEMICOLON, &ast->semicolon_token);
        node = ast;
        return true;
    }

    NamespaceAST *ast = new (_pool) NamespaceAST;
    ast->inline_token = inline_token;
    ast->namespace_token = namespace_token;
    if (LA() == T_IDENTIFIER)
        ast->identifier_token = consumeToken();
    parseOptionalAttributeSpecifierSequence(ast->attribute_list);
    if (isNestedNamespace()) {
        parseNestedNamespace(ast->linkage_body);
    } else if (LA() == T_LBRACE) {
        parseLinkageBody(ast->linkage_body);
    } else { // attempt to do error recovery
        int pos = cursor();
        for (;LA() != T_EOF_SYMBOL; consumeToken()) {
            switch (LA()) {
            case T_IDENTIFIER:
            case T_POUND:
            case T_POUND_POUND:
            case T___ATTRIBUTE__:
            case T_LPAREN:
            case T_RPAREN:
            case T_DEFAULT:
            case T_PUBLIC:
            case T_PRIVATE:
            case T_PROTECTED:
                continue;
            }
            if (tok().isLiteral())
                continue;
            break;
        }
        if (LA() == T_LBRACE && parseLinkageBody(ast->linkage_body))
            warning(pos, "expected '{' before '%s'", _translationUnit->tokenAt(pos).spell());
        else
            rewind(pos);
    }
    node = ast;
    return true;
}

bool Parser::isNestedNamespace() const
{
    return _languageFeatures.cxx11Enabled && LA() == T_COLON_COLON && LA(2) == T_IDENTIFIER;
}

bool Parser::parseNestedNamespace(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    DeclarationAST *ast = nullptr;
    if (isNestedNamespace() && parseNamespace(ast)) {
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseUsing(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_USING)
        return false;

    if (LA(2) == T_NAMESPACE)
        return parseUsingDirective(node);

    if (_languageFeatures.cxx11Enabled && LA(2) == T_IDENTIFIER && parseAliasDeclaration(node))
        return true;

    UsingAST *ast = new (_pool) UsingAST;
    ast->using_token = consumeToken();

    if (LA() == T_TYPENAME)
        ast->typename_token = consumeToken();

    parseName(ast->name);
    match(T_SEMICOLON, &ast->semicolon_token);
    node = ast;
    return true;
}

bool Parser::parseUsingDirective(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_USING && LA(2) == T_NAMESPACE) {
        UsingDirectiveAST *ast = new (_pool) UsingDirectiveAST;
        ast->using_token = consumeToken();
        ast->namespace_token = consumeToken();
        if (! parseName(ast->name))
            warning(cursor(), "expected `namespace name' before `%s'",
                    tok().spell());
        match(T_SEMICOLON, &ast->semicolon_token);
        node = ast;
        return true;
    }
    return false;
}

// alias-declaration = 'using' identifier attribute-specifier-seq(opt) '=' type-id ';'
bool Parser::parseAliasDeclaration(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_USING || LA(2) != T_IDENTIFIER)
        return false;

    if (!find(T_EQUAL, T_SEMICOLON))
        return false;

    AliasDeclarationAST *alias = new (_pool) AliasDeclarationAST;
    alias->using_token = consumeToken();
    SimpleNameAST *name = new (_pool) SimpleNameAST;
    name->identifier_token = consumeToken();
    alias->name = name;

    // ### attributes!
    while (LA() != T_EQUAL)
        consumeToken();

    alias->equal_token = consumeToken();

    ExpressionAST *expr = nullptr;
    parseTypeId(expr);
    if (expr)
        alias->typeId = expr->asTypeId();

    match(T_SEMICOLON, &alias->semicolon_token);

    node = alias;
    return true;
}

bool Parser::parseConversionFunctionId(NameAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_OPERATOR)
        return false;
    int operator_token = consumeToken();
    SpecifierListAST *type_specifier = nullptr;
    if (! parseTypeSpecifier(type_specifier))
        return false;
    PtrOperatorListAST *ptr_operators = nullptr, **ptr_operators_tail = &ptr_operators;
    while (parsePtrOperator(*ptr_operators_tail))
        ptr_operators_tail = &(*ptr_operators_tail)->next;

    ConversionFunctionIdAST *ast = new (_pool) ConversionFunctionIdAST;
    ast->operator_token = operator_token;
    ast->type_specifier_list = type_specifier;
    ast->ptr_operator_list = ptr_operators;
    node = ast;
    return true;
}

bool Parser::parseOperatorFunctionId(NameAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_OPERATOR)
        return false;
    int operator_token = consumeToken();

    OperatorAST *op = nullptr;
    if (! parseOperator(op))
        return false;

    OperatorFunctionIdAST *ast = new (_pool) OperatorFunctionIdAST;
    ast->operator_token = operator_token;
    ast->op = op;
    node = ast;
    return true;
}

Parser::TemplateArgumentListEntry *Parser::templateArgumentListEntry(int tokenIndex)
{
    std::map<int, TemplateArgumentListEntry>::iterator it =_templateArgumentList.find(tokenIndex);
    if (it != _templateArgumentList.end())
        return &it->second;

    return nullptr;
}

bool Parser::parseTemplateArgumentList(ExpressionListAST *&node)
{
    DEBUG_THIS_RULE();

    if (TemplateArgumentListEntry *entry = templateArgumentListEntry(cursor())) {
        rewind(entry->cursor);
        node = entry->ast;
        return entry->ast != nullptr;
    }

    int start = cursor();

    ExpressionListAST **template_argument_ptr = &node;
    ExpressionAST *template_argument = nullptr;
    const bool cxx11Enabled = _languageFeatures.cxx11Enabled;
    if (parseTemplateArgument(template_argument)) {
        *template_argument_ptr = new (_pool) ExpressionListAST;
        (*template_argument_ptr)->value = template_argument;
        template_argument_ptr = &(*template_argument_ptr)->next;

        if (cxx11Enabled && LA() == T_DOT_DOT_DOT)
            consumeToken(); // ### store this token in the AST

        while (LA() == T_COMMA) {
            consumeToken(); // consume T_COMMA

            if (parseTemplateArgument(template_argument)) {
                *template_argument_ptr = new (_pool) ExpressionListAST;
                (*template_argument_ptr)->value = template_argument;
                template_argument_ptr = &(*template_argument_ptr)->next;

                if (cxx11Enabled && LA() == T_DOT_DOT_DOT)
                    consumeToken(); // ### store this token in the AST
            }
        }

        if (_pool != _translationUnit->memoryPool()) {
            MemoryPool *pool = _translationUnit->memoryPool();
            ExpressionListAST *template_argument_list = node;
            for (ExpressionListAST *iter = template_argument_list, **ast_iter = &node;
                 iter; iter = iter->next, ast_iter = &(*ast_iter)->next)
                *ast_iter = new (pool) ExpressionListAST((iter->value) ? iter->value->clone(pool) : nullptr);
        }

        _templateArgumentList.insert(std::make_pair(start, TemplateArgumentListEntry(start, cursor(), node)));
        return true;
    }

    _templateArgumentList.insert(std::make_pair(start, TemplateArgumentListEntry(start, cursor(), nullptr)));
    return false;
}

bool Parser::parseAsmDefinition(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_ASM)
        return false;

    AsmDefinitionAST *ast = new (_pool) AsmDefinitionAST;
    ast->asm_token = consumeToken();

    if (LA() == T_VOLATILE)
        ast->volatile_token = consumeToken();

    match(T_LPAREN, &ast->lparen_token);
    int string_literal_token = 0;
    match(T_STRING_LITERAL, &string_literal_token);
    while (LA() == T_STRING_LITERAL) {
        consumeToken();
    }
    if (LA() == T_COLON) {
        consumeToken(); // skip T_COLON
        parseAsmOperandList();
        if (LA() == T_COLON) {
            consumeToken();
            parseAsmOperandList();
            if (LA() == T_COLON) {
                consumeToken();
                parseAsmClobberList();
            }
        } else if (LA() == T_COLON_COLON) {
            consumeToken();
            parseAsmClobberList();
        }
    } else if (LA() == T_COLON_COLON) {
        consumeToken();
        parseAsmOperandList();

        if (LA() == T_COLON) {
          consumeToken();
          parseAsmClobberList();
        }
    }
    match(T_RPAREN, &ast->rparen_token);
    match(T_SEMICOLON, &ast->semicolon_token);
    node = ast;
    return true;
}

bool Parser::parseAsmOperandList()
{
    DEBUG_THIS_RULE();
    if (LA() != T_STRING_LITERAL)
        return true;

    if (parseAsmOperand()) {
        while (LA() == T_COMMA) {
            consumeToken();
            parseAsmOperand();
        }
        return true;
    }

    return false;
}

bool Parser::parseAsmOperand()
{
    DEBUG_THIS_RULE();
    int string_literal_token = 0;
    match(T_STRING_LITERAL, &string_literal_token);

    if (LA() == T_LBRACKET) {
        /*int lbracket_token = */ consumeToken();
        match(T_STRING_LITERAL, &string_literal_token);
        int rbracket_token = 0;
        match(T_RBRACKET, &rbracket_token);
    }

    int lparen_token = 0, rparen_token = 0;
    match(T_LPAREN, &lparen_token);
    ExpressionAST *expression = nullptr;
    parseExpression(expression);
    match(T_RPAREN, &rparen_token);
    return true;
}

bool Parser::parseAsmClobberList()
{
    DEBUG_THIS_RULE();
    if (LA() != T_STRING_LITERAL)
        return false;

    int string_literal_token = consumeToken();

    while (LA() == T_COMMA) {
        consumeToken();
        match(T_STRING_LITERAL, &string_literal_token);
    }

    return true;
}

bool Parser::parseTemplateDeclaration(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (! (LA(1) == T_TEMPLATE || ((LA(1) == T_EXPORT || LA(1) == T_EXTERN)
            && LA(2) == T_TEMPLATE)))
        return false;

    TemplateDeclarationAST *ast = new (_pool) TemplateDeclarationAST;

    if (LA() == T_EXPORT || LA() == T_EXTERN)
        ast->export_token = consumeToken();

    ast->template_token = consumeToken();

    if (LA() == T_LESS) {
        ast->less_token = consumeToken();
        if (maybeSplitGreaterGreaterToken() || LA() == T_GREATER || parseTemplateParameterList(ast->template_parameter_list))
            match(T_GREATER, &ast->greater_token);
        if (!parseRequiresClauseOpt(ast->requiresClause))
            return false;
    }

    while (LA()) {
        int start_declaration = cursor();

        ast->declaration = nullptr;
        if (parseDeclaration(ast->declaration))
            break;
        if (parseConceptDeclaration(ast->declaration))
            break;

        error(start_declaration, "expected a declaration");
        rewind(start_declaration + 1);
        skipUntilDeclaration();
    }

    node = ast;
    return true;
}

bool Parser::parseConceptDeclaration(DeclarationAST *&node)
{
    if (!_languageFeatures.cxx20Enabled)
        return false;
    if (LA() != T_CONCEPT)
        return false;

    const auto ast = new (_pool) ConceptDeclarationAST;
    ast->concept_token = consumeToken();
    if (!parseName(ast->name))
        return false;
    parseAttributeSpecifier(ast->attributes);
    if (LA() != T_EQUAL)
        return false;
    ast->equals_token = consumeToken();
    if (!parseLogicalOrExpression(ast->constraint))
        return false;
    if (LA() != T_SEMICOLON)
        return false;
    ast->semicolon_token = consumeToken();
    node = ast;
    return true;
}

bool Parser::parsePlaceholderTypeSpecifier(PlaceholderTypeSpecifierAST *&node)
{
    if ((lookAtBuiltinTypeSpecifier() || _translationUnit->tokenAt(_tokenIndex).isKeyword())
        && (LA() != T_AUTO && LA() != T_DECLTYPE)) {
        return false;
    }

    TypeConstraintAST *typeConstraint = nullptr;
    const int savedCursor = cursor();
    parseTypeConstraint(typeConstraint);
    if (LA() != T_AUTO && (LA() != T_DECLTYPE || LA(1) != T_LPAREN || LA(2) != T_AUTO)) {
        rewind(savedCursor);
        return false;
    }
    const auto spec = new (_pool) PlaceholderTypeSpecifierAST;
    spec->typeConstraint = typeConstraint;
    if (LA() == T_DECLTYPE) {
        spec->declTypetoken = consumeToken();
        if (LA() != T_LPAREN)
            return false;
        spec->lparenToken = consumeToken();
        if (LA() != T_AUTO)
            return false;
        spec->autoToken = consumeToken();
        if (LA() != T_RPAREN)
            return false;
        spec->rparenToken = consumeToken();
    } else {
        spec->autoToken = consumeToken();
    }
    node = spec;
    return true;
}

bool Parser::parseTypeConstraint(TypeConstraintAST *&node)
{
    if (!_languageFeatures.cxx20Enabled)
        return false;
    NestedNameSpecifierListAST *nestedName = nullptr;
    parseNestedNameSpecifierOpt(nestedName, true);
    NameAST *conceptName = nullptr;
    if (!parseUnqualifiedName(conceptName, false))
        return false;
    const auto typeConstraint = new (_pool) TypeConstraintAST;
    typeConstraint->nestedName = nestedName;
    typeConstraint->conceptName = conceptName;
    if (LA() != T_LESS) {
        node = typeConstraint;
        return true;
    }
    typeConstraint->lessToken = consumeToken();
    if (LA() != T_GREATER) {
        if (!parseTemplateArgumentList(typeConstraint->templateArgs))
            return false;
    }
    if (LA() != T_GREATER)
        return false;
    typeConstraint->greaterToken = consumeToken();
    node = typeConstraint;
    return true;
}

bool Parser::parseRequirement()
{
    if (LA() == T_TYPENAME) { // type-requirement
        consumeToken();
        NameAST *name = nullptr;
        if (!parseName(name, true))
            return false;
        if (LA() != T_SEMICOLON)
            return false;
        consumeToken();
        return true;
    }
    if (LA() == T_LBRACE) { // compound-requirement
        consumeToken();
        ExpressionAST *expr = nullptr;
        if (!parseExpression(expr))
            return false;
        if (LA() != T_RBRACE)
            return false;
        consumeToken();
        if (LA() == T_NOEXCEPT)
            consumeToken();
        if (LA() == T_SEMICOLON) {
            consumeToken();
            return true;
        }
        TypeConstraintAST *typeConstraint = nullptr;
        if (!parseTypeConstraint(typeConstraint))
            return false;
        if (LA() != T_SEMICOLON)
            return false;
        consumeToken();
        return true;
    }
    if (LA() == T_REQUIRES) { // nested-requirement
        consumeToken();
        ExpressionAST *constraintExpr = nullptr;
        if (!parseLogicalOrExpression(constraintExpr))
            return false;
        if (LA() != T_SEMICOLON)
            return false;
        consumeToken();
        return true;
    }
    ExpressionAST *simpleExpr;
    if (!parseExpression(simpleExpr)) // simple-requirement
        return false;
    if (LA() != T_SEMICOLON)
        return false;
    consumeToken();
    return true;
}

bool Parser::parseRequiresClauseOpt(RequiresClauseAST *&node)
{
    if (!_languageFeatures.cxx20Enabled)
        return true;
    if (LA() != T_REQUIRES)
        return true;
    const auto ast = new (_pool) RequiresClauseAST;
    ast->requires_token = consumeToken();
    if (!parsePrimaryExpression(ast->constraint))
        return false;
    while (true) {
        if (LA() != T_PIPE_PIPE && LA() != T_AMPER_AMPER)
            break;
        ExpressionAST *next = nullptr;
        if (!parsePrimaryExpression(next))
            return false;

        // This won't yield the right precedence, but I don't care.
        BinaryExpressionAST *expr = new (_pool) BinaryExpressionAST;
        expr->left_expression = ast->constraint;
        expr->binary_op_token = consumeToken();
        expr->right_expression = next;
        ast->constraint = expr;
    }
    node = ast;
    return true;
}

bool Parser::parseRequiresExpression(ExpressionAST *&node)
{
    if (!_languageFeatures.cxx20Enabled)
        return false;
    if (LA() != T_REQUIRES)
        return false;

    const auto ast = new (_pool) RequiresExpressionAST;
    ast->requires_token = consumeToken();
    if (LA() == T_LPAREN) {
        ast->lparen_token = consumeToken();
        if (!parseParameterDeclarationClause(ast->parameters))
            return false;
        if (LA() != T_RPAREN)
            return false;
        ast->rparen_token = consumeToken();
    }
    if (LA() != T_LBRACE)
        return false;
    ast->lbrace_token = consumeToken();
    if (!parseRequirement())
        return false;
    while (LA() != T_RBRACE) {
        if (!parseRequirement())
            return false;
    }
    ast->rbrace_token = consumeToken();

    node = ast;
    return true;
}

bool Parser::parseOperator(OperatorAST *&node) // ### FIXME
{
    DEBUG_THIS_RULE();
    OperatorAST *ast = new (_pool) OperatorAST;

    switch (LA()) {
    case T_NEW:
    case T_DELETE: {
        ast->op_token = consumeToken();
        if (LA() == T_LBRACKET) {
            ast->open_token = consumeToken();
            match(T_RBRACKET, &ast->close_token);
        }
    } break;

    case T_PLUS:
    case T_MINUS:
    case T_STAR:
    case T_SLASH:
    case T_PERCENT:
    case T_CARET:
    case T_AMPER:
    case T_PIPE:
    case T_TILDE:
    case T_EXCLAIM:
    case T_LESS:
    case T_GREATER:
    case T_COMMA:
    case T_AMPER_EQUAL:
    case T_CARET_EQUAL:
    case T_SLASH_EQUAL:
    case T_EQUAL:
    case T_EQUAL_EQUAL:
    case T_EXCLAIM_EQUAL:
    case T_GREATER_EQUAL:
    case T_GREATER_GREATER_EQUAL:
    case T_LESS_EQUAL:
    case T_LESS_EQUAL_GREATER:
    case T_LESS_LESS_EQUAL:
    case T_MINUS_EQUAL:
    case T_PERCENT_EQUAL:
    case T_PIPE_EQUAL:
    case T_PLUS_EQUAL:
    case T_STAR_EQUAL:
    case T_TILDE_EQUAL:
    case T_LESS_LESS:
    case T_GREATER_GREATER:
    case T_AMPER_AMPER:
    case T_PIPE_PIPE:
    case T_PLUS_PLUS:
    case T_MINUS_MINUS:
    case T_ARROW_STAR:
    case T_DOT_STAR:
    case T_ARROW:
        ast->op_token = consumeToken();
        break;

    default:
        if (LA() == T_LPAREN && LA(2) == T_RPAREN) {
            ast->op_token = ast->open_token = consumeToken();
            ast->close_token = consumeToken();
        } else if (LA() == T_LBRACKET && LA(2) == T_RBRACKET) {
            ast->op_token = ast->open_token = consumeToken();
            ast->close_token = consumeToken();
        } else if (_languageFeatures.cxx11Enabled &&
                   LA() == T_STRING_LITERAL && LA(2) == T_IDENTIFIER &&
                   !tok().f.userDefinedLiteral && tok().string->size() == 0 &&
                   tok(2).identifier->size() > 1 && tok(2).identifier->chars()[0] == '_') {
            // C++11 user-defined literal operator, e.g.:
            // int operator"" _abc123(const char *str, size_t size) { ... }
            ast->op_token = consumeToken();
            consumeToken(); // consume literal operator identifier
        } else {
            return false;
        }
    }

    node = ast;
    return true;
}

bool Parser::parseCvQualifiers(SpecifierListAST *&node)
{
    DEBUG_THIS_RULE();

    int start = cursor();

    SpecifierListAST **ast = &node;
    while (*ast)
        ast = &(*ast)->next;

    while (int tk = LA()) {
        if (tk == T_CONST || tk == T_VOLATILE) {
            SimpleSpecifierAST *spec = new (_pool) SimpleSpecifierAST;
            spec->specifier_token = consumeToken();
            *ast = new (_pool) SpecifierListAST(spec);
            ast = &(*ast)->next;
        } else if (parseOptionalAttributeSpecifierSequence(*ast)) {
            continue;
        } else {
            break;
        }
    }

    return start != cursor();
}

bool Parser::parseRefQualifier(int &ref_qualifier)
{
    DEBUG_THIS_RULE();

    if (!_languageFeatures.cxx11Enabled)
        return false;

    if (LA() == T_AMPER || LA() == T_AMPER_AMPER) {
        ref_qualifier = consumeToken();
        return true;
    }

    return false;
}

/**
 * \brief Handles override and final from C++ 2011, they are pseudo keywords and has special meaning only in function declaration
 */
bool Parser::parseOverrideFinalQualifiers(SpecifierListAST *&node)
{
    DEBUG_THIS_RULE();

    if (!_languageFeatures.cxx11Enabled)
        return false;

    int start = cursor();

    SpecifierListAST **ast = &node;
    while (*ast)
        ast = &(*ast)->next;

    while (LA() == T_IDENTIFIER) {
        const Identifier &id = *(_translationUnit->tokenAt(cursor()).identifier);

        if (id.equalTo(_control->cpp11Override())
                || id.equalTo(_control->cpp11Final())) {
            SimpleSpecifierAST *spec = new (_pool) SimpleSpecifierAST;
            spec->specifier_token = consumeToken();
            *ast = new (_pool) SpecifierListAST(spec);
            ast = &(*ast)->next;
        }
        else {
            break;
        }
    }

    return (start != cursor());
}

bool Parser::parsePtrOperator(PtrOperatorListAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_AMPER || (_languageFeatures.cxx11Enabled && LA() == T_AMPER_AMPER)) {
        ReferenceAST *ast = new (_pool) ReferenceAST;
        ast->reference_token = consumeToken();
        node = new (_pool) PtrOperatorListAST(ast);
        return true;
    } else if (LA() == T_STAR) {
        PointerAST *ast = new (_pool) PointerAST;
        ast->star_token = consumeToken();
        parseCvQualifiers(ast->cv_qualifier_list);
        node = new (_pool) PtrOperatorListAST(ast);
        return true;
    } else if (LA() == T_COLON_COLON || LA() == T_IDENTIFIER) {
        int scope_or_identifier_token = cursor();

        int global_scope_token = 0;
        if (LA() == T_COLON_COLON)
            global_scope_token = consumeToken();

        NestedNameSpecifierListAST *nested_name_specifiers = nullptr;
        bool has_nested_name_specifier = parseNestedNameSpecifier(nested_name_specifiers, true);
        if (has_nested_name_specifier && LA() == T_STAR) {
            PointerToMemberAST *ast = new (_pool) PointerToMemberAST;
            ast->global_scope_token = global_scope_token;
            ast->nested_name_specifier_list = nested_name_specifiers;
            ast->star_token = consumeToken();
            parseCvQualifiers(ast->cv_qualifier_list);
            node = new (_pool) PtrOperatorListAST(ast);
            return true;
        }
        rewind(scope_or_identifier_token);
    }
    return false;
}

bool Parser::parseTemplateArgument(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    int start = cursor();
    if (parseTypeId(node)) {
        int index = 1;

        if (_languageFeatures.cxx11Enabled && LA() == T_DOT_DOT_DOT)
            index = 2;

        if (LA(index) == T_COMMA || maybeSplitGreaterGreaterToken(index) || LA(index) == T_GREATER)
            return true;
    }

    rewind(start);
    bool previousTemplateArguments = switchTemplateArguments(true);
    bool parsed = parseConstantExpression(node);
    (void) switchTemplateArguments(previousTemplateArguments);
    return parsed;
}

/** Parses a sequence of
 *
 * storage-class-specifier (unless noStorageSpecifier is true)
 * trailing-type-specifier, which contains
 *     cv-qualifier
 *     simple-type-specifier
 *     typename-specifier
 *     elaborated-type-specifier
 *
 * If onlySimpleTypeSpecifiers is true, it only eats simple-type-specifiers
 * and cv-qualifiers.
 */
bool Parser::parseDeclSpecifierSeq(SpecifierListAST *&decl_specifier_seq,
                                   bool noStorageSpecifiers,
                                   bool onlySimpleTypeSpecifiers)
{
    DEBUG_THIS_RULE();
    bool has_type_specifier = false;
    NameAST *named_type_specifier = nullptr;
    SpecifierListAST **decl_specifier_seq_ptr = &decl_specifier_seq;
    for (;;) {
        PlaceholderTypeSpecifierAST *placeholderSpec = nullptr;
        // A simple auto is also technically a placeholder-type-specifier, but for historical
        // reasons, it is handled further below.
        if (LA() != T_AUTO && parsePlaceholderTypeSpecifier(placeholderSpec)) {
            *decl_specifier_seq_ptr = new (_pool) SpecifierListAST(placeholderSpec);
            decl_specifier_seq_ptr = &(*decl_specifier_seq_ptr)->next;
            continue;
        }
        if (! noStorageSpecifiers && ! onlySimpleTypeSpecifiers && lookAtStorageClassSpecifier()) {
            // storage-class-specifier
            SimpleSpecifierAST *spec = new (_pool) SimpleSpecifierAST;
            spec->specifier_token = consumeToken();
            *decl_specifier_seq_ptr = new (_pool) SpecifierListAST(spec);
            decl_specifier_seq_ptr = &(*decl_specifier_seq_ptr)->next;
        } else if (lookAtCVQualifier()) {
            // cv-qualifier
            SimpleSpecifierAST *spec = new (_pool) SimpleSpecifierAST;
            spec->specifier_token = consumeToken();
            *decl_specifier_seq_ptr = new (_pool) SpecifierListAST(spec);
            decl_specifier_seq_ptr = &(*decl_specifier_seq_ptr)->next;
        } else if (! named_type_specifier && lookAtBuiltinTypeSpecifier()) {
            // parts of simple-type-specifier
            parseBuiltinTypeSpecifier(*decl_specifier_seq_ptr);
            decl_specifier_seq_ptr = &(*decl_specifier_seq_ptr)->next;
            has_type_specifier = true;
        } else if (! has_type_specifier && (LA() == T_COLON_COLON ||
                                            LA() == T_IDENTIFIER)) {
            // parts of simple-type-specifier
            if (! parseName(named_type_specifier))
                return false;
            NamedTypeSpecifierAST *spec = new (_pool) NamedTypeSpecifierAST;
            spec->name = named_type_specifier;
            *decl_specifier_seq_ptr = new (_pool) SpecifierListAST(spec);
            decl_specifier_seq_ptr = &(*decl_specifier_seq_ptr)->next;
            has_type_specifier = true;
        } else if (! onlySimpleTypeSpecifiers && ! has_type_specifier &&
                   (LA() == T_TYPENAME || LA() == T_ENUM || lookAtClassKey())) {
            // typename-specifier, elaborated-type-specifier
            int startOfTypeSpecifier = cursor();
            if (! parseElaboratedTypeSpecifier(*decl_specifier_seq_ptr)) {
                rewind(startOfTypeSpecifier);
                if (LA() == T_ENUM) {
                    if (!parseEnumSpecifier(*decl_specifier_seq_ptr)) {
                        error(startOfTypeSpecifier, "expected an enum specifier");
                        break;
                    }
                } else if (lookAtClassKey()) {
                    if (!parseClassSpecifier(*decl_specifier_seq_ptr)) {
                        error(startOfTypeSpecifier, "expected a class specifier");
                        break;
                    }
                } else {
                    error(startOfTypeSpecifier, "expected an elaborated type specifier");
                    break;
                }
            }
            decl_specifier_seq_ptr = &(*decl_specifier_seq_ptr)->next;
            has_type_specifier = true;
        } else {
            break;
        }
    }

    return decl_specifier_seq != nullptr;
}

bool Parser::parseDeclaratorOrAbstractDeclarator(DeclaratorAST *&node, SpecifierListAST *decl_specifier_list)
{
    DEBUG_THIS_RULE();
    int start = cursor();
    bool blocked = blockErrors(true);
    if (parseDeclarator(node, decl_specifier_list)) {
        blockErrors(blocked);
        return true;
    }
    blockErrors(blocked);
    rewind(start);
    return parseAbstractDeclarator(node, decl_specifier_list);
}



bool Parser::parseCoreDeclarator(DeclaratorAST *&node, SpecifierListAST *decl_specifier_list, ClassSpecifierAST *)
{
    DEBUG_THIS_RULE();
    int start = cursor();
    SpecifierListAST *attributes = nullptr;
    parseOptionalAttributeSpecifierSequence(attributes);

    PtrOperatorListAST *ptr_operators = nullptr, **ptr_operators_tail = &ptr_operators;
    while (parsePtrOperator(*ptr_operators_tail))
        ptr_operators_tail = &(*ptr_operators_tail)->next;

    if (LA() == T_COLON_COLON || LA() == T_IDENTIFIER || LA() == T_TILDE || LA() == T_OPERATOR
        || (_languageFeatures.cxx11Enabled && LA() == T_DOT_DOT_DOT && (LA(2) == T_COLON_COLON || LA(2) == T_IDENTIFIER))) {

        int dot_dot_dot_token = 0;

        if (LA() == T_DOT_DOT_DOT)
            dot_dot_dot_token = consumeToken();

        NameAST *name = nullptr;
        if (parseName(name)) {
            DeclaratorIdAST *declarator_id = new (_pool) DeclaratorIdAST;
            declarator_id->dot_dot_dot_token = dot_dot_dot_token;
            declarator_id->name = name;
            DeclaratorAST *ast = new (_pool) DeclaratorAST;
            ast->attribute_list = attributes;
            ast->ptr_operator_list = ptr_operators;
            ast->core_declarator = declarator_id;
            node = ast;
            return true;
        }
    } else if (decl_specifier_list && LA() == T_LPAREN) {
        if (attributes)
            warning(attributes->firstToken(), "unexpected attribtues");

        int lparen_token = consumeToken();
        DeclaratorAST *declarator = nullptr;
        if (parseDeclarator(declarator, decl_specifier_list) && LA() == T_RPAREN) {
            NestedDeclaratorAST *nested_declarator = new (_pool) NestedDeclaratorAST;
            nested_declarator->lparen_token = lparen_token;
            nested_declarator->declarator = declarator;
            nested_declarator->rparen_token = consumeToken();
            DeclaratorAST *ast = new (_pool) DeclaratorAST;
            ast->ptr_operator_list = ptr_operators;
            ast->core_declarator = nested_declarator;
            node = ast;
            return true;
        }
    } else if (const auto decl = parseDecompositionDeclarator(decl_specifier_list)) {
        DeclaratorAST *ast = new (_pool) DeclaratorAST;
        ast->attribute_list = attributes;
        ast->ptr_operator_list = ptr_operators;
        ast->core_declarator = decl;
        node = ast;
        return true;
    }
    rewind(start);
    return false;
}

DecompositionDeclaratorAST *Parser::parseDecompositionDeclarator(
        SpecifierListAST *decl_specifier_list)
{
    if (!_languageFeatures.cxx11Enabled || LA() != T_LBRACKET || !hasAuto(decl_specifier_list))
        return nullptr;
    consumeToken();

    const auto decl = new (_pool) DecompositionDeclaratorAST;
    for (NameListAST **iter = &decl->identifiers; ; iter = &(*iter)->next) {
        if (LA() != T_IDENTIFIER) {
            error(cursor(), "expected an identifier");
            return nullptr;
        }
        SimpleNameAST * const name_ast = new (_pool) SimpleNameAST;
        name_ast->identifier_token = consumeToken();
        *iter = new (_pool) NameListAST;
        (*iter)->value = name_ast;

        if (LA() == T_RBRACKET) {
            consumeToken();
            return decl;
        }

        if (LA() == T_COMMA) {
            consumeToken();
            continue;
        }

        error(cursor(), "expected ',' or ']'");
        return nullptr;
    }

    return nullptr;
}

static bool maybeCppInitializer(DeclaratorAST *declarator)
{
    if (declarator->ptr_operator_list)
        return false;
    CoreDeclaratorAST *core_declarator = declarator->core_declarator;
    if (! core_declarator)
        return false;
    DeclaratorIdAST *declarator_id = core_declarator->asDeclaratorId();
    if (! declarator_id)
        return false;
    else if (! declarator_id->name)
        return false;
    else if (! declarator_id->name->asSimpleName())
        return false;

    return true;
}

bool Parser::hasAuto(SpecifierListAST *decl_specifier_list) const
{
    for (SpecifierListAST *iter = decl_specifier_list; iter; iter = iter->next) {
        SpecifierAST *spec = iter->value;
        if (SimpleSpecifierAST *simpleSpec = spec->asSimpleSpecifier()) {
            if (_translationUnit->tokenKind(simpleSpec->specifier_token) == T_AUTO)
                return true;
        }
        if (spec->asPlaceholderTypeSpecifier())
            return true;
    }
    return false;
}

bool Parser::parseDeclarator(DeclaratorAST *&node, SpecifierListAST *decl_specifier_list, ClassSpecifierAST *declaringClass)
{
    DEBUG_THIS_RULE();
    if (! parseCoreDeclarator(node, decl_specifier_list, declaringClass))
        return false;

    PostfixDeclaratorListAST **postfix_ptr = &node->postfix_declarator_list;

    for (;;) {
        int startOfPostDeclarator = cursor();

        if (LA() == T_LPAREN) {
            if (! declaringClass && LA(2) != T_RPAREN && maybeCppInitializer(node)) {
                int lparen_token = cursor();
                ExpressionAST *initializer = nullptr;

                bool blocked = blockErrors(true);
                if (parseInitializer(initializer, &node->equal_token)) {
                    // maybe the initializer also parses as a FunctionDeclarator?
                    ExpressionListParenAST *expr = nullptr;
                    if (initializer)
                        expr = initializer->asExpressionListParen();
                    if (expr) {
                        if (expr->expression_list && expr->rparen_token && (LA() == T_COMMA || LA() == T_SEMICOLON)) {
                            rewind(lparen_token);

                            // check for ambiguous declarators.

                            consumeToken();
                            ParameterDeclarationClauseAST *parameter_declaration_clause = nullptr;
                            if (parseParameterDeclarationClause(parameter_declaration_clause) && LA() == T_RPAREN) {
                                int rparen_token = consumeToken();

                                FunctionDeclaratorAST *ast = new (_pool) FunctionDeclaratorAST;
                                ast->decl_specifier_list = decl_specifier_list;
                                ast->lparen_token = lparen_token;
                                ast->parameter_declaration_clause = parameter_declaration_clause;
                                ast->as_cpp_initializer = initializer;
                                ast->rparen_token = rparen_token;
                                *postfix_ptr = new (_pool) PostfixDeclaratorListAST(ast);

                                blockErrors(blocked);
                                return true;
                            }


                            blockErrors(blocked);
                            rewind(lparen_token);
                            return true;
                        }
                    }
                }

                blockErrors(blocked);
                rewind(lparen_token);
            }

            FunctionDeclaratorAST *ast = new (_pool) FunctionDeclaratorAST;
            ast->decl_specifier_list = decl_specifier_list;
            ast->lparen_token = consumeToken();
            parseParameterDeclarationClause(ast->parameter_declaration_clause);
            if (LA() != T_RPAREN) {
                rewind(startOfPostDeclarator);
                break;
            }

            ast->rparen_token = consumeToken();
            // ### parse attributes
            parseCvQualifiers(ast->cv_qualifier_list);
            parseRefQualifier(ast->ref_qualifier_token);
            parseExceptionSpecification(ast->exception_specification);

            if (_languageFeatures.cxx11Enabled && ! node->ptr_operator_list && LA() == T_ARROW
                    && hasAuto(decl_specifier_list)) {
                parseTrailingReturnType(ast->trailing_return_type);
            }

            parseOverrideFinalQualifiers(ast->cv_qualifier_list);

            *postfix_ptr = new (_pool) PostfixDeclaratorListAST(ast);
            postfix_ptr = &(*postfix_ptr)->next;
        } else if (LA() == T_LBRACKET) {
            ArrayDeclaratorAST *ast = new (_pool) ArrayDeclaratorAST;
            ast->lbracket_token = consumeToken();
            if (LA() == T_RBRACKET || parseConstantExpression(ast->expression))
                match(T_RBRACKET, &ast->rbracket_token);
            *postfix_ptr = new (_pool) PostfixDeclaratorListAST(ast);
            postfix_ptr = &(*postfix_ptr)->next;
        } else
            break;
    }

    if (LA() == T___ASM__ && LA(2) == T_LPAREN) { // ### store the asm specifier in the AST
        consumeToken(); // skip __asm__
        consumeToken(); // skip T_LPAREN

        if (skipUntil(T_RPAREN))
            consumeToken(); // skip T_RPAREN
    }

    parseOptionalAttributeSpecifierSequence(node->post_attribute_list);
    return true;
}

bool Parser::parseAbstractCoreDeclarator(DeclaratorAST *&node, SpecifierListAST *decl_specifier_list)
{
    DEBUG_THIS_RULE();

    PtrOperatorListAST *ptr_operators = nullptr, **ptr_operators_tail = &ptr_operators;
    while (parsePtrOperator(*ptr_operators_tail))
        ptr_operators_tail = &(*ptr_operators_tail)->next;

    int after_ptr_operators = cursor();

    if (LA() == T_LPAREN && LA(2) != T_RPAREN) {
        int lparen_token = consumeToken();
        DeclaratorAST *declarator = nullptr;
        if (parseAbstractDeclarator(declarator, decl_specifier_list) && LA() == T_RPAREN) {
            NestedDeclaratorAST *nested_declarator = new (_pool) NestedDeclaratorAST;
            nested_declarator->lparen_token = lparen_token;
            nested_declarator->declarator = declarator;
            nested_declarator->rparen_token = consumeToken();
            DeclaratorAST *ast = new (_pool) DeclaratorAST;
            ast->ptr_operator_list = ptr_operators;
            ast->core_declarator = nested_declarator;
            node = ast;
            return true;
        }
    }

    rewind(after_ptr_operators);
    if (ptr_operators) {
        DeclaratorAST *ast = new (_pool) DeclaratorAST;
        ast->ptr_operator_list = ptr_operators;
        node = ast;
    }

    return true;
}

bool Parser::parseAbstractDeclarator(DeclaratorAST *&node, SpecifierListAST *decl_specifier_list)
{
    DEBUG_THIS_RULE();
    if (! parseAbstractCoreDeclarator(node, decl_specifier_list))
        return false;

    PostfixDeclaratorListAST *postfix_declarators = nullptr,
        **postfix_ptr = &postfix_declarators;

    for (;;) {
        if (LA() == T_LPAREN) {
            FunctionDeclaratorAST *ast = new (_pool) FunctionDeclaratorAST;
            ast->decl_specifier_list = decl_specifier_list;
            ast->lparen_token = consumeToken();
            if (LA() == T_RPAREN || parseParameterDeclarationClause(ast->parameter_declaration_clause)) {
                if (LA() == T_RPAREN)
                    ast->rparen_token = consumeToken();
            }
            parseCvQualifiers(ast->cv_qualifier_list);
            parseRefQualifier(ast->ref_qualifier_token);
            parseExceptionSpecification(ast->exception_specification);
            *postfix_ptr = new (_pool) PostfixDeclaratorListAST(ast);
            postfix_ptr = &(*postfix_ptr)->next;
        } else if (LA() == T_LBRACKET) {
            ArrayDeclaratorAST *ast = new (_pool) ArrayDeclaratorAST;
            ast->lbracket_token = consumeToken();
            if (LA() == T_RBRACKET || parseConstantExpression(ast->expression)) {
                if (LA() == T_RBRACKET)
                    ast->rbracket_token = consumeToken();
            }
            *postfix_ptr = new (_pool) PostfixDeclaratorListAST(ast);
            postfix_ptr = &(*postfix_ptr)->next;
        } else
            break;
    }

    if (postfix_declarators) {
        if (! node)
            node = new (_pool) DeclaratorAST;

        node->postfix_declarator_list = postfix_declarators;
    }

    return true;
}

/**
 * @brief Reads enumeration type declaration, examples:
 * @code
    enum {
        debug = 1
    };
    enum class Format {
        FormatPNG,
        FormatJPEG
    };
 * @endcode
 */
bool Parser::parseEnumSpecifier(SpecifierListAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_ENUM) {
        EnumSpecifierAST *ast = new (_pool) EnumSpecifierAST;

        ast->enum_token = consumeToken();
        if (_languageFeatures.cxx11Enabled && (LA() == T_CLASS || LA() == T_STRUCT))
            ast->key_token = consumeToken();


        if (tok().isKeyword()) {
            error(cursor(), "expected identifier before '%s'", tok().spell());
            return false;
        }

        if (LA() == T_COLON_COLON || LA() == T_IDENTIFIER)
            parseName(ast->name);

        if (_languageFeatures.cxx11Enabled && LA() == T_COLON) {
            ast->colon_token = consumeToken();
            parseTypeSpecifier(ast->type_specifier_list);
        }
        if (LA() == T_LBRACE) {
            ast->lbrace_token = consumeToken();
            int comma_token = 0;
            EnumeratorListAST **enumerator_ptr = &ast->enumerator_list;
            while (int tk = LA()) {
                if (tk == T_RBRACE)
                    break;

                if (LA() != T_IDENTIFIER) {
                    error(cursor(), "expected identifier before '%s'", tok().spell());
                    skipUntil(T_IDENTIFIER);
                }

                if (parseEnumerator(*enumerator_ptr))
                    enumerator_ptr = &(*enumerator_ptr)->next;

                if (LA() == T_COMMA && LA(2) == T_RBRACE)
                    ast->stray_comma_token = consumeToken();

                if (LA() != T_RBRACE)
                    match(T_COMMA, &comma_token);
            }
            match(T_RBRACE, &ast->rbrace_token);
        } else if (!_languageFeatures.cxx11Enabled) {
            return false;
        }

        node = new (_pool) SpecifierListAST(ast);
        return true;
    }
    return false;
}

bool Parser::parseTemplateParameterList(DeclarationListAST *&node)
{
    DEBUG_THIS_RULE();
    DeclarationListAST **template_parameter_ptr = &node;
    DeclarationAST *declaration = nullptr;
    if (parseTemplateParameter(declaration)) {
        *template_parameter_ptr = new (_pool) DeclarationListAST;
        (*template_parameter_ptr)->value = declaration;
        template_parameter_ptr = &(*template_parameter_ptr)->next;

        while (LA() == T_COMMA) {
            consumeToken(); // XXX Store this token somewhere

            declaration = nullptr;
            if (parseTemplateParameter(declaration)) {
                *template_parameter_ptr = new (_pool) DeclarationListAST;
                (*template_parameter_ptr)->value = declaration;
                template_parameter_ptr = &(*template_parameter_ptr)->next;
            }
        }
        return true;
    }
    return false;
}

bool Parser::parseTemplateParameter(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (parseTypeParameter(node))
        return true;
    bool previousTemplateArguments = switchTemplateArguments(true);
    ParameterDeclarationAST *ast = nullptr;
    bool parsed = parseParameterDeclaration(ast);
    node = ast;
    (void) switchTemplateArguments(previousTemplateArguments);
    return parsed;
}

bool Parser::parseTypenameTypeParameter(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_CLASS || LA() == T_TYPENAME) {
        TypenameTypeParameterAST *ast = new (_pool) TypenameTypeParameterAST;
        ast->classkey_token = consumeToken();
        if (_languageFeatures.cxx11Enabled && LA() == T_DOT_DOT_DOT)
            ast->dot_dot_dot_token = consumeToken();
        parseName(ast->name);
        if (LA() == T_EQUAL) {
            ast->equal_token = consumeToken();
            parseTypeId(ast->type_id);
        }
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseTemplateTypeParameter(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    TemplateTypeParameterAST *ast = new (_pool) TemplateTypeParameterAST;
    if (LA() == T_TEMPLATE) {
        ast->template_token = consumeToken();
        if (LA() == T_LESS)
            ast->less_token = consumeToken();
        parseTemplateParameterList(ast->template_parameter_list);
        if (maybeSplitGreaterGreaterToken() || LA() == T_GREATER)
            ast->greater_token = consumeToken();
        if (LA() == T_CLASS)
            ast->class_token = consumeToken();
    } else if (!parseTypeConstraint(ast->typeConstraint)) {
        return false;
    }
    if (_languageFeatures.cxx11Enabled && LA() == T_DOT_DOT_DOT)
        ast->dot_dot_dot_token = consumeToken();

    // parse optional name
    parseName(ast->name);

    if (LA() == T_EQUAL) {
        ast->equal_token = consumeToken();
        parseTypeId(ast->type_id);
    }
    node = ast;
    return true;
}

bool Parser::lookAtTypeParameter()
{
    if (LA() == T_CLASS || LA() == T_TYPENAME) {
        if (LA(2) == T_IDENTIFIER) {
            switch (LA(3)) {
            case T_EQUAL:
            case T_COMMA:
            case T_GREATER:
                return true;

            default:
                return maybeSplitGreaterGreaterToken(3);
            }
        } else if (LA(2) == T_COLON_COLON) {
            // found something like template <typename ::foo::bar>...
            return false;
        }

        // recognized an anonymous template type parameter. e.g
        //    template <typename>
        return true;
    }

    return false;
}


bool Parser::parseTypeParameter(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();

    if (lookAtTypeParameter())
        return parseTypenameTypeParameter(node);
    if (LA() == T_TEMPLATE)
        return parseTemplateTypeParameter(node);
    return parseTemplateTypeParameter(node);
}

bool Parser::parseTypeId(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    CHECK_CACHE(ASTCache::TypeId, ExpressionAST);

    SpecifierListAST *type_specifier = nullptr;
    if (parseTypeSpecifier(type_specifier)) {
        TypeIdAST *ast = new (_pool) TypeIdAST;
        ast->type_specifier_list = type_specifier;
        parseAbstractDeclarator(ast->declarator, type_specifier);
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseParameterDeclarationClause(ParameterDeclarationClauseAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_RPAREN)
        return true; // nothing to do
    CHECK_CACHE(ASTCache::ParameterDeclarationClause, ParameterDeclarationClauseAST);
    const int initialCursor = cursor();

    ParameterDeclarationListAST *parameter_declarations = nullptr;

    int dot_dot_dot_token = 0;
    if (LA() == T_DOT_DOT_DOT)
        dot_dot_dot_token = consumeToken();
    else {
        parseParameterDeclarationList(parameter_declarations);

        if (LA() == T_DOT_DOT_DOT) {
            dot_dot_dot_token = consumeToken();
        } else if (LA() == T_COMMA && LA(2) == T_DOT_DOT_DOT) {
            consumeToken(); // skip comma
            dot_dot_dot_token = consumeToken();
        }
    }

    if (parameter_declarations || dot_dot_dot_token) {
        ParameterDeclarationClauseAST *ast = new (_pool) ParameterDeclarationClauseAST;
        ast->parameter_declaration_list = parameter_declarations;
        ast->dot_dot_dot_token = dot_dot_dot_token;
        node = ast;
    }

    const bool result = true;
    _astCache->insert(ASTCache::ParameterDeclarationClause, initialCursor, node, cursor(), result);
    return result;
}

bool Parser::parseParameterDeclarationList(ParameterDeclarationListAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_DOT_DOT_DOT || (LA() == T_COMMA && LA(2) == T_DOT_DOT_DOT))
        return false; // nothing to do.

    ParameterDeclarationListAST **parameter_declaration_ptr = &node;
    ParameterDeclarationAST *declaration = nullptr;
    if (parseParameterDeclaration(declaration)) {
        *parameter_declaration_ptr = new (_pool) ParameterDeclarationListAST;
        (*parameter_declaration_ptr)->value = declaration;
        parameter_declaration_ptr = &(*parameter_declaration_ptr)->next;
        while (LA() == T_COMMA) {
            consumeToken();

            if (LA() == T_DOT_DOT_DOT)
                break;

            declaration = nullptr;
            if (parseParameterDeclaration(declaration)) {
                *parameter_declaration_ptr = new (_pool) ParameterDeclarationListAST;
                (*parameter_declaration_ptr)->value = declaration;
                parameter_declaration_ptr = &(*parameter_declaration_ptr)->next;
            }
        }
        return true;
    }
    return false;
}

bool Parser::parseParameterDeclaration(ParameterDeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (_languageFeatures.cxx11Enabled) {
        SpecifierListAST *attr_specifier_seq = nullptr;
        while (parseStdAttributeSpecifier(attr_specifier_seq))
            ;
    }
    SpecifierListAST *decl_specifier_seq = nullptr;
    if (parseDeclSpecifierSeq(decl_specifier_seq)) {
        ParameterDeclarationAST *ast = new (_pool) ParameterDeclarationAST;
        ast->type_specifier_list = decl_specifier_seq;
        parseDeclaratorOrAbstractDeclarator(ast->declarator, decl_specifier_seq);
        if (LA() == T_EQUAL) {
            ast->equal_token = consumeToken();
            if (!_languageFeatures.cxx11Enabled)
                parseLogicalOrExpression(ast->expression);
            else
                parseInitializerClause0x(ast->expression);
        }

        node = ast;
        return true;
    }
    return false;
}

const Identifier *Parser::className(ClassSpecifierAST *ast) const
{
  if (! ast)
    return nullptr;

  return identifier(ast->name);
}

const Identifier *Parser::identifier(NameAST *name) const
{
  if (! name)
    return nullptr;

  if (QualifiedNameAST *q = name->asQualifiedName())
    name = q->unqualified_name;

  if (name) {
    if (SimpleNameAST *simple = name->asSimpleName())
      return _translationUnit->identifier(simple->identifier_token);
    else if (TemplateIdAST *template_id = name->asTemplateId())
      return _translationUnit->identifier(template_id->identifier_token);
  }

  return nullptr;
}

bool Parser::parseClassSpecifier(SpecifierListAST *&node)
{
    DEBUG_THIS_RULE();
    if (! lookAtClassKey())
        return false;

    int classkey_token = consumeToken();

    SpecifierListAST *attributes = nullptr;
    parseOptionalAttributeSpecifierSequence(attributes);

    if (LA(1) == T_IDENTIFIER && LA(2) == T_IDENTIFIER) {
        const Identifier *id = tok(2).identifier;
        if (!id->equalTo(_control->cpp11Final())) {
            warning(cursor(), "skip identifier `%s'",
                                      tok().spell());
            consumeToken();
        }
    }

    NameAST *name = nullptr;
    parseName(name);

    bool parsed = false;

    const bool previousInFunctionBody = _inFunctionBody;
    _inFunctionBody = false;

    int colon_token = 0;
    int dot_dot_dot_token = 0;
    int final_token = 0;

    if (LA() == T_IDENTIFIER) {
        const Identifier *id = tok().identifier;
        if (id->equalTo(_control->cpp11Final()))
            final_token = consumeToken();
    }

    if (LA() == T_COLON || LA() == T_LBRACE) {
        if (!name) {
            AnonymousNameAST *ast = new (_pool) AnonymousNameAST;
            ast->class_token = classkey_token;
            name = ast;
        }

        BaseSpecifierListAST *base_clause_list = nullptr;

        if (LA() == T_COLON) {
            colon_token = cursor();

            parseBaseClause(base_clause_list);

            if (_languageFeatures.cxx11Enabled && LA() == T_DOT_DOT_DOT)
                dot_dot_dot_token = consumeToken();

            if (LA() != T_LBRACE) {
                error(cursor(), "expected `{' before `%s'", tok().spell());

                const int saved = cursor();

                for (int n = 0; n < 3 && LA() != T_EOF_SYMBOL; ++n, consumeToken()) {
                    if (LA() == T_LBRACE)
                        break;
                }

                if (LA() != T_LBRACE)
                    rewind(saved);
            }
        }

        ClassSpecifierAST *ast = new (_pool) ClassSpecifierAST;
        ast->classkey_token = classkey_token;
        ast->attribute_list = attributes;
        ast->final_token = final_token;
        ast->name = name;
        ast->colon_token = colon_token;
        ast->base_clause_list = base_clause_list;
        ast->dot_dot_dot_token = dot_dot_dot_token;

        if (LA() == T_LBRACE)
            ast->lbrace_token = consumeToken();

        DeclarationListAST **declaration_ptr = &ast->member_specifier_list;
        while (int tk = LA()) {
            if (tk == T_RBRACE) {
                ast->rbrace_token = consumeToken();
                break;
            }

            int start_declaration = cursor();
            DeclarationAST *declaration = nullptr;
            if (parseMemberSpecification(declaration, ast)) {
                if (declaration) {  // paranoia check
                    *declaration_ptr = new (_pool) DeclarationListAST;
                    (*declaration_ptr)->value = declaration;
                    declaration_ptr = &(*declaration_ptr)->next;
                }

                if (cursor() == start_declaration) { // more paranoia
                    rewind(start_declaration + 1);
                    skipUntilDeclaration();
                }
            } else {
                error(start_declaration, "expected a declaration");
                rewind(start_declaration + 1);
                skipUntilDeclaration();
            }
        }
        node = new (_pool) SpecifierListAST(ast);
        parsed = true;
    }

    _inFunctionBody = previousInFunctionBody;

    return parsed;
}

bool Parser::parseAccessDeclaration(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_PUBLIC || LA() == T_PROTECTED || LA() == T_PRIVATE || LA() == T_Q_SIGNALS || LA() == T_Q_SLOTS) {
        bool isSignals = LA() == T_Q_SIGNALS;
        bool isSlots = LA() == T_Q_SLOTS;
        AccessDeclarationAST *ast = new (_pool) AccessDeclarationAST;
        ast->access_specifier_token = consumeToken();
        if (! isSignals && (LA() == T_Q_SLOTS || isSlots))
            ast->slots_token = consumeToken();
        match(T_COLON, &ast->colon_token);
        node = ast;
        return true;
    }
    return false;
}

/*
 Q_PROPERTY(type name
    (READ getFunction [WRITE setFunction]
        | MEMBER memberName [(READ getFunction | WRITE setFunction)])
    [RESET resetFunction]
    [NOTIFY notifySignal]
    [REVISION int]
    [DESIGNABLE bool]
    [SCRIPTABLE bool]
    [STORED bool]
    [USER bool]
    [BINDABLE bindableFunction]
    [CONSTANT]
    [FINAL])

    Note that "type" appears to be any valid type. So these are valid:
      Q_PROPERTY(const char *zoo READ zoo)
      Q_PROPERTY(const class Blah *blah READ blah)

    Furthermore, the only restriction on the order of the items in between the
    parenthesis is that the type is the first parameter and the name comes after
    the type. Especially, there seems to be no restriction on the READ/WRITE/MEMBER
    order.
*/
bool Parser::parseQtPropertyDeclaration(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    const bool privateProperty = (LA() == T_Q_PRIVATE_PROPERTY);
    if (LA() != T_Q_PROPERTY && !privateProperty)
        return false;

    QtPropertyDeclarationAST *ast = new (_pool)QtPropertyDeclarationAST;
    ast->property_specifier_token = consumeToken();
    if (LA() == T_LPAREN) {
        ast->lparen_token = consumeToken();

        if (privateProperty) {
            if (parsePostfixExpression(ast->expression)) {
                match(T_COMMA, &ast->comma_token);
            } else {
                error(cursor(), "expected expression before `%s'", tok().spell());
                return true;
            }
        }

        parseTypeId(ast->type_id);

        SimpleNameAST *property_name = new (_pool) SimpleNameAST;
        // special case: keywords are allowed for property names!
        if (tok().isKeyword())
            property_name->identifier_token = consumeToken();
        else
            match(T_IDENTIFIER, &property_name->identifier_token);

        ast->property_name = property_name;
        QtPropertyDeclarationItemListAST **iter = &ast->property_declaration_item_list;
        while (true) {
            if (LA() == T_RPAREN) {
                ast->rparen_token = consumeToken();
                node = ast;
                break;
            } else if (LA() == T_IDENTIFIER) {
                QtPropertyDeclarationItemAST *item = nullptr;
                switch (peekAtQtContextKeyword()) {
                case Token_READ:
                case Token_WRITE:
                case Token_MEMBER:
                case Token_BINDABLE:
                case Token_RESET:
                case Token_NOTIFY:
                case Token_REVISION:
                case Token_DESIGNABLE:
                case Token_SCRIPTABLE:
                case Token_STORED:
                case Token_USER: {
                    int item_name_token = consumeToken();
                    ExpressionAST *expr = nullptr;
                    if (parsePostfixExpression(expr)) {
                        QtPropertyDeclarationItemAST *bItem =
                                new (_pool) QtPropertyDeclarationItemAST;
                        bItem->item_name_token = item_name_token;
                        bItem->expression = expr;
                        item = bItem;
                    } else {
                        error(cursor(), "expected expression before `%s'", tok().spell());
                    }
                    break;
                }

                case Token_CONSTANT:
                case Token_FINAL: {
                    QtPropertyDeclarationItemAST *fItem = new (_pool) QtPropertyDeclarationItemAST;
                    fItem->item_name_token = consumeToken();
                    item = fItem;
                    break;
                }

                default:
                    error(cursor(), "expected `)' before `%s'", tok().spell());
                    // skip the token
                    consumeToken();
                }
                if (item) {
                    *iter = new (_pool) QtPropertyDeclarationItemListAST;
                    (*iter)->value = item;
                    iter = &(*iter)->next;
                }
            } else if (!LA()) {
                break;
            } else {
                error(cursor(), "expected `)' before `%s'", tok().spell());
                // skip the token
                consumeToken();
            }
        }
    }
    return true;
}

// q-enums-decl ::= 'Q_ENUMS' '(' q-enums-list? ')'
// q-enums-list ::= identifier
// q-enums-list ::= q-enums-list identifier
//
// Note: Q_ENUMS is a CPP macro with exactly 1 parameter.
// Examples of valid uses:
//   Q_ENUMS()
//   Q_ENUMS(Priority)
//   Q_ENUMS(Priority Severity)
// so, these are not allowed:
//   Q_ENUMS
//   Q_ENUMS(Priority, Severity)
bool Parser::parseQtEnumDeclaration(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_Q_ENUMS)
        return false;

    QtEnumDeclarationAST *ast = new (_pool) QtEnumDeclarationAST;
    ast->enum_specifier_token = consumeToken();
    match(T_LPAREN, &ast->lparen_token);
    for (NameListAST **iter = &ast->enumerator_list; LA() && LA() != T_RPAREN; iter = &(*iter)->next) {
        NameAST *name_ast = nullptr;
        if (!parseName(name_ast))
            break;
        *iter = new (_pool) NameListAST;
        (*iter)->value = name_ast;
    }
    match(T_RPAREN, &ast->rparen_token);
    node = ast;
    return true;
}

// q-flags-decl ::= 'Q_FLAGS' '(' q-flags-list? ')'
// q-flags-list ::= identifier
// q-flags-list ::= q-flags-list identifier
//
// Note: Q_FLAGS is a CPP macro with exactly 1 parameter.
// Examples of valid uses:
//   Q_FLAGS()
//   Q_FLAGS(Orientation)
//   Q_FLAGS(Orientation DropActions)
// so, these are not allowed:
//   Q_FLAGS
//   Q_FLAGS(Orientation, DropActions)
bool Parser::parseQtFlags(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_Q_FLAGS)
        return false;

    QtFlagsDeclarationAST *ast = new (_pool) QtFlagsDeclarationAST;
    ast->flags_specifier_token = consumeToken();
    match(T_LPAREN, &ast->lparen_token);
    for (NameListAST **iter = &ast->flag_enums_list; LA() && LA() != T_RPAREN; iter = &(*iter)->next) {
        NameAST *name_ast = nullptr;
        if (!parseName(name_ast))
            break;
        *iter = new (_pool) NameListAST;
        (*iter)->value = name_ast;
    }
    match(T_RPAREN, &ast->rparen_token);
    node = ast;
    return true;
}

// class-specifier ::=
//   c++-class-specifier
//   q-tag
//   q-enums-of-flags
//   q-class-info
//   q-interfaces
//   q-private-slot
//
// declaration ::=
//   c++-declaration
//   q-declare-interface
//   q-declare-metatype
//
// q-tag ::=
//   Q_OBJECT
//   Q_GADGET
//
// q-enums-or-flags ::=
//   (Q_ENUMS | Q_FLAGS) LPAREN name+ RPAREN
//
// q-class-info ::=
//   Q_CLASS_INFO LPAREN string-literal COMMA STRING_LITERAL RPAREN
//   Q_CLASS_INFO LPAREN string-literal COMMA IDENTIFIER LPAREN STRING_LITERAL RPAREN RPAREN

// q-interfaces ::=
//   Q_INTERFACES LPAREN (name q-constraints)* RPAREN
//
// q-constraints ::=
//   (COLON name)*
bool Parser::parseQtInterfaces(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_Q_INTERFACES)
        return false;

    QtInterfacesDeclarationAST *ast = new (_pool) QtInterfacesDeclarationAST;
    ast->interfaces_token = consumeToken();
    match(T_LPAREN, &ast->lparen_token);
    for (QtInterfaceNameListAST **iter = &ast->interface_name_list; LA() && LA() != T_RPAREN; iter = &(*iter)->next) {
        NameAST *name_ast = nullptr;
        if (!parseName(name_ast))
            break;
        *iter = new (_pool) QtInterfaceNameListAST;
        (*iter)->value = new (_pool) QtInterfaceNameAST;
        (*iter)->value->interface_name = name_ast;
        for (NameListAST **iter2 = &(*iter)->value->constraint_list; LA() && LA() == T_COLON; iter2 = &(*iter2)->next) {
            /*int colon_token =*/ consumeToken();
            NameAST *name_ast2 = nullptr;
            if (!parseName(name_ast2))
                break;
            *iter2 = new (_pool) NameListAST;
            (*iter2)->value = name_ast2;
        }
    }

    match(T_RPAREN, &ast->rparen_token);
    node = ast;
    return true;
}

// q-private-slot ::=
//   Q_PRIVATE_SLOT LPAREN IDENTIFIER (LPAREN RPAREN)? COMMA q-function-declaration RPAREN
//
// q-function-declaration ::=
//   decl-specifier-list declarator   [+ check for the function-declarator]
//
// q-declare-interface ::=
//   Q_DECLARE_INTERFACE LPAREN name COMMA (STRING_LITERAL | IDENTIFIER) RPAREN
//
// q-declare-metatype ::=
//   Q_DECLARE_METATYPE LPAREN name RPAREN SEMICOLON? [warning]

bool Parser::parseMemberSpecification(DeclarationAST *&node, ClassSpecifierAST *declaringClass)
{
    DEBUG_THIS_RULE();
    const ASTCache::CacheKey cacheKey(cursor(), ASTCache::MemberSpecification);
    CHECK_CACHE(cacheKey.astKind, DeclarationAST);

    switch (LA()) {
    case T_Q_OBJECT:
    case T_Q_GADGET:
    {
        QtObjectTagAST *ast = new (_pool) QtObjectTagAST;
        ast->q_object_token = consumeToken();
        node = ast;
        CACHE_AND_RETURN(cacheKey, true);
    }

    case T_Q_PRIVATE_SLOT:
    {
        QtPrivateSlotAST *ast = new (_pool) QtPrivateSlotAST;
        ast->q_private_slot_token = consumeToken();
        match(T_LPAREN, &ast->lparen_token);
        match(T_IDENTIFIER, &ast->dptr_token);
        if (LA() == T_LPAREN) {
            ast->dptr_lparen_token = consumeToken();
            match(T_RPAREN, &ast->dptr_rparen_token);
        }
        match(T_COMMA, &ast->comma_token);
        (void) parseTypeSpecifier(ast->type_specifier_list);
        parseDeclarator(ast->declarator, ast->type_specifier_list);
        match(T_RPAREN, &ast->rparen_token);
        node = ast;
    }   CACHE_AND_RETURN(cacheKey, true);

    case T_SEMICOLON:
        CACHE_AND_RETURN(cacheKey, parseEmptyDeclaration(node));

    case T_USING:
        CACHE_AND_RETURN(cacheKey, parseUsing(node));

    case T_TEMPLATE:
        CACHE_AND_RETURN(cacheKey, parseTemplateDeclaration(node));

    case T_Q_SIGNALS:
    case T_PUBLIC:
    case T_PROTECTED:
    case T_PRIVATE:
    case T_Q_SLOTS:
        CACHE_AND_RETURN(cacheKey, parseAccessDeclaration(node));

    case T_Q_PROPERTY:
    case T_Q_PRIVATE_PROPERTY:
        CACHE_AND_RETURN(cacheKey, parseQtPropertyDeclaration(node));

    case T_Q_ENUMS:
        CACHE_AND_RETURN(cacheKey, parseQtEnumDeclaration(node));

    case T_Q_FLAGS:
        CACHE_AND_RETURN(cacheKey, parseQtFlags(node));

    case T_Q_INTERFACES:
        CACHE_AND_RETURN(cacheKey, parseQtInterfaces(node));

    case T_STATIC_ASSERT:
        if (_languageFeatures.cxx11Enabled)
            CACHE_AND_RETURN(cacheKey, parseStaticAssertDeclaration(node));
        Q_FALLTHROUGH();

    default:
        CACHE_AND_RETURN(cacheKey, parseSimpleDeclaration(node, declaringClass));
    } // switch
}

bool Parser::parseCtorInitializer(CtorInitializerAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_COLON) {
        int colon_token = consumeToken();

        CtorInitializerAST *ast = new (_pool) CtorInitializerAST;
        ast->colon_token = colon_token;

        parseMemInitializerList(ast->member_initializer_list);

        if (_languageFeatures.cxx11Enabled && LA() == T_DOT_DOT_DOT)
            ast->dot_dot_dot_token = consumeToken();

        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseElaboratedTypeSpecifier(SpecifierListAST *&node)
{
    DEBUG_THIS_RULE();
    if (lookAtClassKey() || LA() == T_ENUM || LA() == T_TYPENAME) {
        int classkey_token = consumeToken();

        SpecifierListAST *attributes = nullptr;
        parseOptionalAttributeSpecifierSequence(attributes);
        NameAST *name = nullptr;
        if (parseName(name)) {
            ElaboratedTypeSpecifierAST *ast = new (_pool) ElaboratedTypeSpecifierAST;
            ast->classkey_token = classkey_token;
            ast->attribute_list = attributes;
            ast->name = name;
            node = new (_pool) SpecifierListAST(ast);
            return true;
        }
    }
    return false;
}

bool Parser::parseExceptionSpecification(ExceptionSpecificationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_THROW) {
        DynamicExceptionSpecificationAST *ast = new (_pool) DynamicExceptionSpecificationAST;
        ast->throw_token = consumeToken();
        if (LA() == T_LPAREN)
            ast->lparen_token = consumeToken();
        if (LA() == T_DOT_DOT_DOT)
            ast->dot_dot_dot_token = consumeToken();
        else
            parseTypeIdList(ast->type_id_list);
        if (LA() == T_RPAREN)
            ast->rparen_token = consumeToken();
        node = ast;
        return true;
    } else if (_languageFeatures.cxx11Enabled && LA() == T_NOEXCEPT) {
        NoExceptSpecificationAST *ast = new (_pool) NoExceptSpecificationAST;
        ast->noexcept_token = consumeToken();
        if (LA() == T_LPAREN) {
            ast->lparen_token = consumeToken();
            parseConstantExpression(ast->expression);
            match(T_RPAREN, &ast->rparen_token);
        }
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseEnumerator(EnumeratorListAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_IDENTIFIER) {
        EnumeratorAST *ast = new (_pool) EnumeratorAST;
        ast->identifier_token = consumeToken();

        if (LA() == T_EQUAL) {
            ast->equal_token = consumeToken();
            parseConstantExpression(ast->expression);
        }

        node = new (_pool) EnumeratorListAST;
        node->value = ast;
        return true;
    }
    return false;
}

bool Parser::parseInitDeclarator(DeclaratorAST *&node, SpecifierListAST *decl_specifier_list,
                                 ClassSpecifierAST *declaringClass) // ### rewrite me
{
    DEBUG_THIS_RULE();

    if (declaringClass && LA() == T_COLON) {
        // anonymous bit-field declaration.

    } else if (! parseDeclarator(node, decl_specifier_list, declaringClass)) {
        return false;
    }

    if (LA() == T_ASM && LA(2) == T_LPAREN) { // ### FIXME
        consumeToken();

        if (skip(T_LPAREN, T_RPAREN))
            consumeToken();
    }

    const bool isFunctionDeclarator = node
            && node->postfix_declarator_list
            && node->postfix_declarator_list->lastValue()
            && node->postfix_declarator_list->lastValue()->asFunctionDeclarator();
    if (declaringClass && LA() == T_COLON
            && (! node || ! node->postfix_declarator_list)) {
        int colon_token = consumeToken();
        ExpressionAST *expression = nullptr;
        if (parseConstantExpression(expression) && (LA() == T_COMMA ||
                                                    LA() == T_SEMICOLON)) {
            // recognized a bitfielddeclarator.
            if (! node)
                node = new (_pool) DeclaratorAST;
            node->initializer = expression;
            return true;
        }
        rewind(colon_token);
    } else if (isFunctionDeclarator && node->core_declarator && LA() == T_EQUAL && LA(3) == T_SEMICOLON) { // = 0, = delete, = default
        if (!_languageFeatures.cxx11Enabled || LA(2) == T_NUMERIC_LITERAL) {
            parseInitializer(node->initializer, &node->equal_token);
        } else {
            if (LA(2) != T_NUMERIC_LITERAL && LA(2) != T_DEFAULT && LA(2) != T_DELETE) {
                error(cursor(), "expected 'default', 'delete' or '0', got '%s'", tok(2).spell());
                return false;
            }

            node->equal_token = consumeToken();

            IdExpressionAST *id_expr = new (_pool) IdExpressionAST;
            node->initializer = id_expr;

            SimpleNameAST *simple_name = new (_pool) SimpleNameAST;
            id_expr->name = simple_name;
            simple_name->identifier_token = consumeToken();
        }
    } else if (node->core_declarator && (LA() == T_EQUAL || (_languageFeatures.cxx11Enabled && !isFunctionDeclarator && LA() == T_LBRACE) || (! declaringClass && LA() == T_LPAREN))) {
        parseInitializer(node->initializer, &node->equal_token);
    } else if (node->core_declarator && node->core_declarator->asDecompositionDeclarator()) {
        error(cursor(), "structured binding needs initializer");
        return false;
    } else if (!parseRequiresClauseOpt(node->requiresClause)) {
        return false;
    }
    return true;
}

bool Parser::parseBaseClause(BaseSpecifierListAST *&node)
{
    DEBUG_THIS_RULE();

    if (LA() == T_COLON) {
        consumeToken(); // ### remove me

        BaseSpecifierListAST **ast = &node;
        if (parseBaseSpecifier(*ast)) {
            ast = &(*ast)->next;

            while (LA() == T_COMMA) {
                consumeToken(); // consume T_COMMA

                if (parseBaseSpecifier(*ast))
                    ast = &(*ast)->next;
            }
        }

        return true;
    }
    return false;
}

bool Parser::parseInitializer(ExpressionAST *&node, int *equals_token)
{
    DEBUG_THIS_RULE();

    return parseInitializer0x(node, equals_token);
}

bool Parser::parseInitializer0x(ExpressionAST *&node, int *equals_token)
{
    DEBUG_THIS_RULE();

    if ((_languageFeatures.cxx11Enabled && LA() == T_LBRACE) || LA() == T_EQUAL) {
        if (LA() == T_EQUAL)
            *equals_token = cursor();

        return parseBraceOrEqualInitializer0x(node);
    }

    else if (LA() == T_LPAREN) {
        return parseExpressionListParen(node);
    }

    return false;
}

bool Parser::parseBraceOrEqualInitializer0x(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_EQUAL) {
        consumeToken();
        parseInitializerClause0x(node);
        return true;

    } else if (LA() == T_LBRACE) {
        return parseBracedInitList0x(node);

    }

    return false;
}

/*
    initializer-clause:
        assignment-expression
        braced-init-list
        designated-initializer

    If the next token is a T_LBRACKET, it could be the begin of either

        * a C++11 lambda-introducer (parsed by parseAssignmentExpression)
        * or a C99 designator (parsed by parseDesignatedInitializer).

    Because currently C99 and C++11 Support is activated at the same time,
    first try to parse the assignment-expression. If this fails, try to
    parse a designated-initializer.

    TODO:
        As soon as there will be only "one active language", parse either
        the assignment-expression or the designated-initializer, not both.
 */
bool Parser::parseInitializerClause0x(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_LBRACE)
        return parseBracedInitList0x(node);

    if (parseAssignmentExpression(node))
        return true;
    return parseDesignatedInitializer(node);
}

bool Parser::parseInitializerList0x(ExpressionListAST *&node)
{
    DEBUG_THIS_RULE();
    ExpressionListAST **expression_list_ptr = &node;
    ExpressionAST *expression = nullptr;

    _initializerClauseDepth.push(1);

    if (parseInitializerClause0x(expression)) {
        *expression_list_ptr = new (_pool) ExpressionListAST;
        (*expression_list_ptr)->value = expression;
        expression_list_ptr = &(*expression_list_ptr)->next;

        if (_languageFeatures.cxx11Enabled && LA() == T_DOT_DOT_DOT && (LA(2) == T_COMMA || LA(2) == T_RBRACE || LA(2) == T_RPAREN))
            consumeToken(); // ### create an argument pack

        for (++_initializerClauseDepth.top();
                LA() == T_COMMA
                    && LA(2) != T_RBRACE
                    && _initializerClauseDepth.top() <= MAX_EXPRESSION_DEPTH;
             ++_initializerClauseDepth.top()) {
            consumeToken(); // consume T_COMMA

            if (parseInitializerClause0x(expression)) {
                *expression_list_ptr = new (_pool) ExpressionListAST;
                (*expression_list_ptr)->value = expression;

                if (_languageFeatures.cxx11Enabled && LA() == T_DOT_DOT_DOT && (LA(2) == T_COMMA || LA(2) == T_RBRACE || LA(2) == T_RPAREN))
                    consumeToken(); // ### create an argument pack

                expression_list_ptr = &(*expression_list_ptr)->next;
            }
        }
    }

    const bool result = _initializerClauseDepth.top() <= MAX_EXPRESSION_DEPTH;
    _initializerClauseDepth.pop();
    if (!result)
        warning(cursor(), "Reached parse limit for initializer clause");
    return result;
}

bool Parser::parseBracedInitList0x(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_LBRACE)
        return false;

    BracedInitializerAST *ast = new (_pool) BracedInitializerAST;
    ast->lbrace_token = consumeToken();

    parseInitializerList0x(ast->expression_list);

    if (LA() == T_COMMA && LA(2) == T_RBRACE)
        ast->comma_token = consumeToken();

    match(T_RBRACE, &ast->rbrace_token);
    node = ast;
    return true;
}

bool Parser::parseMemInitializerList(MemInitializerListAST *&node)
{
    DEBUG_THIS_RULE();
    MemInitializerListAST **initializer = &node;

    if (parseMemInitializer(*initializer)) {
        initializer = &(*initializer)->next;

        while (true) {

            if (LA() == T_LBRACE)
                break;

            else if (_languageFeatures.cxx11Enabled && LA() == T_DOT_DOT_DOT && LA(2) == T_LBRACE)
                break;

            else if (LA() == T_COMMA
                     || (LA() == T_IDENTIFIER
                         && (LA(2) == T_LPAREN || LA(2) == T_COLON_COLON || (_languageFeatures.cxx11Enabled && LA(2) == T_LBRACE)))) {
                if (LA() != T_COMMA)
                    error(cursor(), "expected `,'");
                else
                    consumeToken();

                if (parseMemInitializer(*initializer))
                    initializer = &(*initializer)->next;
                else
                    error(cursor(), "expected a member initializer");

            } else break;
        }

        if (_languageFeatures.cxx11Enabled && LA() == T_DOT_DOT_DOT) {
            if (LA(2) != T_LBRACE)
                error(cursor(), "expected `{'");

        } else if (LA() != T_LBRACE) {
            error(cursor(), "expected `{'");
        }

        return true;
    }

    return false;
}

bool Parser::parseMemInitializer(MemInitializerListAST *&node)
{
    DEBUG_THIS_RULE();
    NameAST *name = nullptr;
    if (! parseName(name))
        return false;

    MemInitializerAST *ast = new (_pool) MemInitializerAST;
    ast->name = name;

    if (LA() == T_LPAREN) {
        parseExpressionListParen(ast->expression);
    } else if (_languageFeatures.cxx11Enabled && LA() == T_LBRACE) {
        parseBracedInitList0x(ast->expression);
    } else {
        if (!_languageFeatures.cxx11Enabled)
            error(cursor(), "expected '('");
        else
            error(cursor(), "expected '(' or '{'");
        return false;
    }

    node = new (_pool) MemInitializerListAST;
    node->value = ast;
    return true;
}

bool Parser::parseTypeIdList(ExpressionListAST *&node)
{
    DEBUG_THIS_RULE();
    ExpressionListAST **expression_list_ptr = &node;
    ExpressionAST *typeId = nullptr;
    if (parseTypeId(typeId)) {
        *expression_list_ptr = new (_pool) ExpressionListAST;
        (*expression_list_ptr)->value = typeId;
        expression_list_ptr = &(*expression_list_ptr)->next;

        if (_languageFeatures.cxx11Enabled && LA() == T_DOT_DOT_DOT)
            consumeToken(); // ### store this token

        while (LA() == T_COMMA) {
            consumeToken();

            if (parseTypeId(typeId)) {
                *expression_list_ptr = new (_pool) ExpressionListAST;
                (*expression_list_ptr)->value = typeId;
                expression_list_ptr = &(*expression_list_ptr)->next;

                if (_languageFeatures.cxx11Enabled && LA() == T_DOT_DOT_DOT)
                    consumeToken(); // ### store this token
            }
        }
        return true;
    }

    return false;
}

bool Parser::parseExpressionList(ExpressionListAST *&node)
{
    DEBUG_THIS_RULE();
    CHECK_CACHE(ASTCache::ExpressionList, ExpressionListAST);
    int initialCursor = cursor();

    if (_languageFeatures.cxx11Enabled) {
        const bool result = parseInitializerList0x(node);
        _astCache->insert(ASTCache::ExpressionList, initialCursor, (AST *) node, cursor(), result);
        return result;
    }

    ExpressionListAST **expression_list_ptr = &node;
    ExpressionAST *expression = nullptr;
    if (parseAssignmentExpression(expression)) {
        *expression_list_ptr = new (_pool) ExpressionListAST;
        (*expression_list_ptr)->value = expression;
        expression_list_ptr = &(*expression_list_ptr)->next;
        while (LA() == T_COMMA) {
            consumeToken(); // consume T_COMMA

            if (parseAssignmentExpression(expression)) {
                *expression_list_ptr = new (_pool) ExpressionListAST;
                (*expression_list_ptr)->value = expression;
                expression_list_ptr = &(*expression_list_ptr)->next;
            }
        }
        const bool result = true;
        _astCache->insert(ASTCache::ExpressionList, initialCursor, (AST *) node, cursor(), result);
        return result;
    }

    const bool result = false;
    _astCache->insert(ASTCache::ExpressionList, initialCursor, nullptr, cursor(), result);
    return result;
}

bool Parser::parseBaseSpecifier(BaseSpecifierListAST *&node)
{
    DEBUG_THIS_RULE();
    BaseSpecifierAST *ast = new (_pool) BaseSpecifierAST;

    if (LA() == T_VIRTUAL) {
        ast->virtual_token = consumeToken();

        int tk = LA();
        if (tk == T_PUBLIC || tk == T_PROTECTED || tk == T_PRIVATE)
            ast->access_specifier_token = consumeToken();
    } else {
        int tk = LA();
        if (tk == T_PUBLIC || tk == T_PROTECTED || tk == T_PRIVATE)
            ast->access_specifier_token = consumeToken();

        if (LA() == T_VIRTUAL)
            ast->virtual_token = consumeToken();
    }

    parseName(ast->name);
    if (! ast->name)
        error(cursor(), "expected class-name");

    // a name can have ellipsis in case of C++11
    // note: the id must be unqualified then - TODO
    if (_languageFeatures.cxx11Enabled && LA() == T_DOT_DOT_DOT)
        ast->ellipsis_token = consumeToken();

    node = new (_pool) BaseSpecifierListAST;
    node->value = ast;
    return true;
}

bool Parser::parseInitializerList(ExpressionListAST *&node)
{
    DEBUG_THIS_RULE();
    ExpressionListAST **initializer_ptr = &node;
    ExpressionAST *initializer = nullptr;
    if (parseInitializerClause(initializer)) {
        *initializer_ptr = new (_pool) ExpressionListAST;
        (*initializer_ptr)->value = initializer;
        initializer_ptr = &(*initializer_ptr)->next;
        while (LA() == T_COMMA) {
            consumeToken(); // consume T_COMMA
            initializer = nullptr;
            parseInitializerClause(initializer);
            *initializer_ptr = new (_pool) ExpressionListAST;
            (*initializer_ptr)->value = initializer;
            initializer_ptr = &(*initializer_ptr)->next;
        }
    }

    if (_languageFeatures.cxx11Enabled && LA() == T_DOT_DOT_DOT)
        consumeToken(); // ### store this token

    return true;
}

bool Parser::parseInitializerClause(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_LBRACE) {
        ArrayInitializerAST *ast = new (_pool) ArrayInitializerAST;
        ast->lbrace_token = consumeToken();
        parseInitializerList(ast->expression_list);
        match(T_RBRACE, &ast->rbrace_token);
        node = ast;
        return true;
    }
    return parseAssignmentExpression(node);
}

bool Parser::parseUnqualifiedName(NameAST *&node, bool acceptTemplateId)
{
    DEBUG_THIS_RULE();
    if (LA() == T_TILDE && LA(2) == T_IDENTIFIER) {
        DestructorNameAST *ast = new (_pool) DestructorNameAST;
        ast->tilde_token = consumeToken();
        parseUnqualifiedName(ast->unqualified_name);
        node = ast;
        return true;
    } else if (LA() == T_OPERATOR) {
        int operator_token = cursor();
        if (parseOperatorFunctionId(node))
            return true;
        rewind(operator_token);
        return parseConversionFunctionId(node);
     } else if (LA() == T_IDENTIFIER) {
        int identifier_token = cursor();
        if (acceptTemplateId && LA(2) == T_LESS) {
            bool blocked = blockErrors(true);
            if (parseTemplateId(node)
                    && (! _templateArguments || (LA() == T_COMMA  || maybeSplitGreaterGreaterToken() || LA() == T_GREATER ||
                                                 LA() == T_LPAREN || LA() == T_RPAREN  ||
                                                 LA() == T_STAR || LA() == T_AMPER || // ptr-operators
                                                 LA() == T_COLON_COLON))) {
                blockErrors(blocked);
                return true;
            }
            blockErrors(blocked);
        }
        rewind(identifier_token);
        SimpleNameAST *ast = new (_pool) SimpleNameAST;
        ast->identifier_token = consumeToken();
        node = ast;
        return true;
    } else if (LA() == T_TEMPLATE) {
        int template_token = consumeToken();
        if (parseTemplateId(node, template_token))
            return true;
        rewind(template_token);
    }
    return false;
}

bool Parser::parseStringLiteral(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (! (LA() == T_STRING_LITERAL
           || LA() == T_WIDE_STRING_LITERAL
           || LA() == T_UTF8_STRING_LITERAL
           || LA() == T_UTF16_STRING_LITERAL
           || LA() == T_UTF32_STRING_LITERAL
           || LA() == T_RAW_STRING_LITERAL
           || LA() == T_RAW_WIDE_STRING_LITERAL
           || LA() == T_RAW_UTF8_STRING_LITERAL
           || LA() == T_RAW_UTF16_STRING_LITERAL
           || LA() == T_RAW_UTF32_STRING_LITERAL)) {
        return false;
    }

    StringLiteralAST **ast = reinterpret_cast<StringLiteralAST **> (&node);

    while (LA() == T_STRING_LITERAL
           || LA() == T_WIDE_STRING_LITERAL
           || LA() == T_UTF8_STRING_LITERAL
           || LA() == T_UTF16_STRING_LITERAL
           || LA() == T_UTF32_STRING_LITERAL
           || LA() == T_RAW_STRING_LITERAL
           || LA() == T_RAW_WIDE_STRING_LITERAL
           || LA() == T_RAW_UTF8_STRING_LITERAL
           || LA() == T_RAW_UTF16_STRING_LITERAL
           || LA() == T_RAW_UTF32_STRING_LITERAL) {
        *ast = new (_pool) StringLiteralAST;
        (*ast)->literal_token = consumeToken();
        ast = &(*ast)->next;
    }
    return true;
}

bool Parser::parseExpressionStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_SEMICOLON) {
        ExpressionStatementAST *ast = new (_pool) ExpressionStatementAST;
        match(T_SEMICOLON, &ast->semicolon_token);
        node = ast;
        return true;
    }

    const bool wasInExpressionStatement = _inExpressionStatement;
    _inExpressionStatement = true;

    // switch to the temp pool and cache
    MemoryPool *previousPool = _pool;
    _pool = &_expressionStatementTempPool;
    ASTCache *previousASTCache = _astCache;
    _astCache = _expressionStatementAstCache;

    bool parsed = false;

    ExpressionAST *expression = nullptr;
    if (parseExpression(expression)) {
        ExpressionStatementAST *ast = new (previousPool) ExpressionStatementAST;
        if (expression)
            ast->expression = expression->clone(previousPool);
        match(T_SEMICOLON, &ast->semicolon_token);
        node = ast;
        parsed = true;
    }

    _inExpressionStatement = wasInExpressionStatement;

    if (! _inExpressionStatement) {
        // rewind the memory pool and cache after parsing a toplevel expression statement.
        _expressionStatementTempPool.reset();
        _astCache->clear();
    }

    // restore the pool and cache
    _pool = previousPool;
    _astCache = previousASTCache;

    return parsed;
}

bool Parser::parseStatement(StatementAST *&node, bool blockLabeledStatement)
{
    DEBUG_THIS_RULE();
    switch (LA()) {
    case T_WHILE:
        return parseWhileStatement(node);

    case T_DO:
        return parseDoStatement(node);

    case T_Q_FOREACH:
        return parseForeachStatement(node);

    case T_FOR:
        return parseForStatement(node);

    case T_IF:
        return parseIfStatement(node);

    case T_SWITCH:
        return parseSwitchStatement(node);

    case T_TRY:
        return parseTryBlockStatement(node, nullptr);

    case T_CASE:
    case T_DEFAULT:
        if (blockLabeledStatement)
            return false;
        return parseLabeledStatement(node);

    case T_BREAK:
        return parseBreakStatement(node);

    case T_CONTINUE:
        return parseContinueStatement(node);

    case T_GOTO:
        return parseGotoStatement(node);

    case T_RETURN:
    case T_CO_RETURN:
        return parseReturnStatement(node);

    case T_LBRACE:
        return parseCompoundStatement(node);

    case T_ASM:
    case T_NAMESPACE:
    case T_USING:
    case T_TEMPLATE:
    case T_CLASS: case T_STRUCT: case T_UNION:
        return parseDeclarationStatement(node);

    case T_SEMICOLON: {
        ExpressionStatementAST *ast = new (_pool) ExpressionStatementAST;
        ast->semicolon_token = consumeToken();
        node = ast;
        return true;
    }

    case T_AT_TRY:
        return _languageFeatures.objCEnabled && parseObjCTryStatement(node);

    case T_AT_SYNCHRONIZED:
        return _languageFeatures.objCEnabled && parseObjCSynchronizedStatement(node);

    case T_AT_THROW:
        return _languageFeatures.objCEnabled && parseObjCThrowStatement(node);

    case T_Q_D:
    case T_Q_Q: {
        QtMemberDeclarationAST *ast = new (_pool) QtMemberDeclarationAST;
        ast->q_token = consumeToken();
        match(T_LPAREN, &ast->lparen_token);
        parseTypeId(ast->type_id);
        match(T_RPAREN, &ast->rparen_token);
        node = ast;
    } return true;

    case T_EMIT:
    case T_Q_EMIT: {
        // Simply skip the emit token and parse as an expression statement - no strong
        // reason to have an specific ast type.
        consumeToken();
        ExpressionAST *expression = nullptr;
        if (parsePostfixExpression(expression)) {
            ExpressionStatementAST *ast = new (_pool) ExpressionStatementAST;
            ast->expression = expression;
            match(T_SEMICOLON, &ast->semicolon_token);
            node = ast;
            return true;
        }
        error(cursor(), "expected statement");
        return false;
    }

    default:
        if (LA() == T_IDENTIFIER && LA(2) == T_COLON) {
            if (blockLabeledStatement)
                return false;
            return parseLabeledStatement(node);
        }

        return parseExpressionOrDeclarationStatement(node);
    } // switch
    return false; //Avoid compiler warning
}

bool Parser::parseBreakStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_BREAK) {
        BreakStatementAST *ast = new (_pool) BreakStatementAST;
        ast->break_token = consumeToken();
        match(T_SEMICOLON, &ast->semicolon_token);
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseContinueStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_CONTINUE) {
        ContinueStatementAST *ast = new (_pool) ContinueStatementAST;
        ast->continue_token = consumeToken();
        match(T_SEMICOLON, &ast->semicolon_token);
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseGotoStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_GOTO) {
        GotoStatementAST *ast = new (_pool) GotoStatementAST;
        ast->goto_token = consumeToken();
        match(T_IDENTIFIER, &ast->identifier_token);
        match(T_SEMICOLON, &ast->semicolon_token);
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseReturnStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_RETURN || LA() == T_CO_RETURN) {
        ReturnStatementAST *ast = new (_pool) ReturnStatementAST;
        ast->return_token = consumeToken();
        if (_languageFeatures.cxx11Enabled && LA() == T_LBRACE)
            parseBracedInitList0x(ast->expression);
        else
            parseExpression(ast->expression);
        match(T_SEMICOLON, &ast->semicolon_token);
        node = ast;
        return true;
    }
    return false;
}

bool Parser::maybeAmbiguousStatement(DeclarationStatementAST *ast, StatementAST *&node)
{
  const int start = ast->firstToken();
  const int end = ast->lastToken();
  const bool blocked = blockErrors(true);

  bool maybeAmbiguous = false;

  StatementAST *stmt = nullptr;
  if (parseExpressionStatement(stmt)) {
    if (stmt->firstToken() == start && stmt->lastToken() == end) {
      maybeAmbiguous = true;
      node = stmt;
    }
  }

  rewind(end);
  (void) blockErrors(blocked);
  return maybeAmbiguous;
}

bool Parser::parseExpressionOrDeclarationStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();

    if (LA() == T_SEMICOLON)
        return parseExpressionStatement(node);

    const int start = cursor();

    if (lookAtCVQualifier()
            || lookAtStorageClassSpecifier()
            || lookAtBuiltinTypeSpecifier()
            || LA() == T_TYPENAME
            || LA() == T_ENUM
            || lookAtClassKey()
            || (LA() == T_STATIC_ASSERT && _languageFeatures.cxx11Enabled)) {
        return parseDeclarationStatement(node);
    }

    if (LA() == T_IDENTIFIER || (LA() == T_COLON_COLON && LA(2) == T_IDENTIFIER)) {
        const bool blocked = blockErrors(true);

        ExpressionAST *expression = nullptr;
        const bool hasExpression = parseExpression(expression);
        const int afterExpression = cursor();

        if (hasExpression/* && LA() == T_SEMICOLON*/) {
            //const int semicolon_token = consumeToken();
            int semicolon_token = 0;
            if (LA() == T_SEMICOLON)
                semicolon_token = cursor();

            ExpressionStatementAST *as_expression = new (_pool) ExpressionStatementAST;
            as_expression->expression = expression;
            as_expression->semicolon_token = semicolon_token;
            node = as_expression; // well, at least for now.

            bool invalidAssignment = false;
            if (BinaryExpressionAST *binary = expression->asBinaryExpression()) {
                const int binop = _translationUnit->tokenKind(binary->binary_op_token);
                if (binop == T_EQUAL) {
                    if (! binary->left_expression->asBinaryExpression()) {
                        (void) blockErrors(blocked);
                        node = as_expression;
                        match(T_SEMICOLON, &as_expression->semicolon_token);
                        return true;
                    } else {
                        invalidAssignment = true;
                    }
                }
            } else if (CallAST *call = expression->asCall()) {
                if (call->base_expression->asIdExpression() != nullptr) {
                    (void) blockErrors(blocked);
                    node = as_expression;
                    match(T_SEMICOLON, &as_expression->semicolon_token);
                    return true;
                }
            }

            rewind(start);

            DeclarationAST *declaration = nullptr;
            if (parseSimpleDeclaration(declaration)) {
                DeclarationStatementAST *as_declaration = new (_pool) DeclarationStatementAST;
                as_declaration->declaration = declaration;

                SimpleDeclarationAST *simple = declaration->asSimpleDeclaration();
                if (! semicolon_token || invalidAssignment || semicolon_token != simple->semicolon_token ||
                        (simple->decl_specifier_list != nullptr && simple->declarator_list != nullptr)) {
                    node = as_declaration;
                    (void) blockErrors(blocked);
                    return true;
                }

                ExpressionOrDeclarationStatementAST *ast = new (_pool) ExpressionOrDeclarationStatementAST;
                ast->declaration = as_declaration;
                ast->expression = as_expression;
                node = ast;
                (void) blockErrors(blocked);
                return true;
            }

            (void) blockErrors(blocked);

            rewind(afterExpression);
            match(T_SEMICOLON, &as_expression->semicolon_token);
            return true;
        }

        rewind(start);
        (void) blockErrors(blocked);

        return parseDeclarationStatement(node);
    }

    rewind(start);
    return parseExpressionStatement(node);
}

bool Parser::parseCondition(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    int start = cursor();

    bool blocked = blockErrors(true);
    SpecifierListAST *type_specifier = nullptr;
    if (parseTypeSpecifier(type_specifier)) {
        DeclaratorAST *declarator = nullptr;
        if (parseInitDeclarator(declarator, type_specifier, /*declaringClass=*/ nullptr)) {
            if (declarator->initializer && declarator->equal_token) {
                ConditionAST *ast = new (_pool) ConditionAST;
                ast->type_specifier_list = type_specifier;
                ast->declarator = declarator;
                node = ast;
                blockErrors(blocked);
                return true;
            }
        }
    }

    blockErrors(blocked);
    rewind(start);
    return parseExpression(node);
}

bool Parser::parseWhileStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_WHILE) {
        WhileStatementAST *ast = new (_pool) WhileStatementAST;
        ast->while_token = consumeToken();
        match(T_LPAREN, &ast->lparen_token);
        parseCondition(ast->condition);
        match(T_RPAREN, &ast->rparen_token);
        parseStatement(ast->statement);
        node = ast;
        return true;
    }
    return true;
}

bool Parser::parseDoStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_DO) {
        DoStatementAST *ast = new (_pool) DoStatementAST;
        ast->do_token = consumeToken();
        parseStatement(ast->statement);
        match(T_WHILE, &ast->while_token);
        match(T_LPAREN, &ast->lparen_token);
        parseExpression(ast->expression);
        match(T_RPAREN, &ast->rparen_token);
        match(T_SEMICOLON, &ast->semicolon_token);
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseForeachStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_Q_FOREACH) {
        ForeachStatementAST *ast = new (_pool) ForeachStatementAST;
        ast->foreach_token = consumeToken();
        match(T_LPAREN, &ast->lparen_token);

        int startOfTypeSpecifier = cursor();
        bool blocked = blockErrors(true);

        if (parseTypeSpecifier(ast->type_specifier_list))
            parseDeclarator(ast->declarator, ast->type_specifier_list);

        if (! ast->type_specifier_list || ! ast->declarator) {
            ast->type_specifier_list = nullptr;
            ast->declarator = nullptr;

            blockErrors(blocked);
            rewind(startOfTypeSpecifier);
            parseAssignmentExpression(ast->initializer);
        }

        blockErrors(blocked);

        match(T_COMMA, &ast->comma_token);
        parseExpression(ast->expression);
        match(T_RPAREN, &ast->rparen_token);
        parseStatement(ast->statement);

        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseForStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_FOR)
        return false;

    int for_token = consumeToken();
    int lparen_token = 0;
    match(T_LPAREN, &lparen_token);

    int startOfTypeSpecifier = cursor();
    bool blocked = blockErrors(true);

    if (_languageFeatures.objCEnabled) {
        ObjCFastEnumerationAST *ast = new (_pool) ObjCFastEnumerationAST;
        ast->for_token = for_token;
        ast->lparen_token = lparen_token;

        if (parseTypeSpecifier(ast->type_specifier_list))
            parseDeclarator(ast->declarator, ast->type_specifier_list);

        if ((ast->type_specifier_list || ast->declarator) && !peekAtObjCContextKeyword(Token_in)) {
            // woops, probably parsed too much: "in" got parsed as a declarator. Let's redo it:
            ast->type_specifier_list = nullptr;
            ast->declarator = nullptr;

            rewind(startOfTypeSpecifier);
            parseDeclarator(ast->declarator, ast->type_specifier_list);
        }

        if (! ast->type_specifier_list || ! ast->declarator) {
            ast->type_specifier_list = nullptr;
            ast->declarator = nullptr;

            rewind(startOfTypeSpecifier);
            parseAssignmentExpression(ast->initializer);
        }

        if (parseObjCContextKeyword(Token_in, ast->in_token)) {
            blockErrors(blocked);

            parseExpression(ast->fast_enumeratable_expression);
            match(T_RPAREN, &ast->rparen_token);
            parseStatement(ast->statement);

            node = ast;
            return true;
        }

        // there was no "in" token, so we continue with a normal for-statement
        rewind(startOfTypeSpecifier);
    }

    if (_languageFeatures.cxx11Enabled) {
        RangeBasedForStatementAST *ast = new (_pool) RangeBasedForStatementAST;
        ast->for_token = for_token;
        ast->lparen_token = lparen_token;

        if (parseTypeSpecifier(ast->type_specifier_list))
            parseDeclarator(ast->declarator, ast->type_specifier_list);

        if ((ast->type_specifier_list || ast->declarator) && LA() == T_COLON) {
            ast->colon_token = consumeToken();
            blockErrors(blocked);

            if (LA() == T_LBRACE)
                parseBracedInitList0x(ast->expression);
            else
                parseExpression(ast->expression);
            match(T_RPAREN, &ast->rparen_token);
            parseStatement(ast->statement);

            // We need both type specifier and declarator for C++11 range-based for
            if (!ast->type_specifier_list || !ast->declarator)
               error(for_token, "expected declaration with type specifier");

            node = ast;
            return true;
        }
        rewind(startOfTypeSpecifier);
    }

    blockErrors(blocked);

    // Normal C/C++ for-statement parsing
    ForStatementAST *ast = new (_pool) ForStatementAST;

    ast->for_token = for_token;
    ast->lparen_token = lparen_token;
    parseForInitStatement(ast->initializer);
    parseCondition(ast->condition);
    match(T_SEMICOLON, &ast->semicolon_token);
    parseExpression(ast->expression);
    match(T_RPAREN, &ast->rparen_token);
    parseStatement(ast->statement);

    node = ast;
    return true;
}

bool Parser::parseForInitStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    return parseExpressionOrDeclarationStatement(node);
}

bool Parser::parseCompoundStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_LBRACE) {
        if (_statementDepth > MAX_STATEMENT_DEPTH)
            return false;
        ++_statementDepth;

        CompoundStatementAST *ast = new (_pool) CompoundStatementAST;
        ast->lbrace_token = consumeToken();

        // ### TODO: the GNU "local label" extension: "__label__ X, Y, Z;"
        // These are only allowed at the start of a compound stmt regardless of the language.

        StatementListAST **statement_ptr = &ast->statement_list;
        while (int tk = LA()) {
            if (tk == T_RBRACE)
                break;

            int start_statement = cursor();
            StatementAST *statement = nullptr;
            if (! parseStatement(statement)) {
                rewind(start_statement + 1);
                skipUntilStatement();
            } else {
                *statement_ptr = new (_pool) StatementListAST;
                (*statement_ptr)->value = statement;
                statement_ptr = &(*statement_ptr)->next;
            }
        }
        match(T_RBRACE, &ast->rbrace_token);
        node = ast;
        --_statementDepth;
        return true;
    }
    return false;
}

bool Parser::parseIfStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_IF) {
        IfStatementAST *ast = new (_pool) IfStatementAST;
        ast->if_token = consumeToken();
        if (LA() == T_CONSTEXPR) {
            // "if constexpr" added in cxx17, but we don't check cxx version here
            // because msvc 2019 compiler uses "if constexpr" in headers despite cxx version set for the project
            ast->constexpr_token = consumeToken();
        }
        match(T_LPAREN, &ast->lparen_token);

        // C++17: init-statement
        if (_languageFeatures.cxx17Enabled) {
            const int savedCursor = cursor();
            const bool savedBlockErrors = _translationUnit->blockErrors(true);
            bool foundInitStmt = parseExpressionOrDeclarationStatement(ast->initStmt);
            if (foundInitStmt)
                foundInitStmt = ast->initStmt;
            if (foundInitStmt) {
                if (const auto exprStmt = ast->initStmt->asExpressionStatement()) {
                    foundInitStmt = exprStmt->semicolon_token;
                } else if (const auto declStmt = ast->initStmt->asDeclarationStatement()) {
                    foundInitStmt = declStmt->declaration
                            && declStmt->declaration->asSimpleDeclaration()
                            && declStmt->declaration->asSimpleDeclaration()->semicolon_token;
                } else {
                    foundInitStmt = false;
                }
            }
            if (!foundInitStmt) {
                ast->initStmt = nullptr;
                rewind(savedCursor);
            }
            _translationUnit->blockErrors(savedBlockErrors);
        }
        parseCondition(ast->condition);
        match(T_RPAREN, &ast->rparen_token);
        if (! parseStatement(ast->statement))
            error(cursor(), "expected statement");
        if (LA() == T_ELSE) {
            ast->else_token = consumeToken();
            if (! parseStatement(ast->else_statement))
                error(cursor(), "expected statement");
        }
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseSwitchStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_SWITCH) {
        SwitchStatementAST *ast = new (_pool) SwitchStatementAST;
        ast->switch_token = consumeToken();
        match(T_LPAREN, &ast->lparen_token);
        parseCondition(ast->condition);
        match(T_RPAREN, &ast->rparen_token);
        parseStatement(ast->statement);
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseLabeledStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    switch (LA()) {
    case T_IDENTIFIER:
        if (LA(2) == T_COLON) {
            LabeledStatementAST *ast = new (_pool) LabeledStatementAST;
            ast->label_token = consumeToken();
            ast->colon_token = consumeToken();
            parseStatement(ast->statement, /*blockLabeledStatement =*/ true);
            node = ast;
            return true;
        }
        break;

    case T_DEFAULT: {
        LabeledStatementAST *ast = new (_pool) LabeledStatementAST;
        ast->label_token = consumeToken();
        match(T_COLON, &ast->colon_token);
        parseStatement(ast->statement, /*blockLabeledStatement =*/ true);
        node = ast;
        return true;
    }

    case T_CASE: {
        CaseStatementAST *ast = new (_pool) CaseStatementAST;
        ast->case_token = consumeToken();
        parseConstantExpression(ast->expression);
        match(T_COLON, &ast->colon_token);
        parseStatement(ast->statement, /*blockLabeledStatement =*/ true);
        node = ast;
        return true;
    }

    default:
        break;
    } // switch
    return false;
}

bool Parser::parseBlockDeclaration(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    switch (LA()) {
    case T_USING:
        return parseUsing(node);

    case T_ASM:
        return parseAsmDefinition(node);

    case T_NAMESPACE:
        return parseNamespaceAliasDefinition(node);

    case T_STATIC_ASSERT:
        if (_languageFeatures.cxx11Enabled)
            return parseStaticAssertDeclaration(node);
        Q_FALLTHROUGH();

    default:
        return parseSimpleDeclaration(node);
    } // switch

}

bool Parser::parseNamespaceAliasDefinition(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_NAMESPACE && LA(2) == T_IDENTIFIER && LA(3) == T_EQUAL) {
        NamespaceAliasDefinitionAST *ast = new (_pool) NamespaceAliasDefinitionAST;
        ast->namespace_token = consumeToken();
        ast->namespace_name_token = consumeToken();
        ast->equal_token = consumeToken();
        parseName(ast->name);
        match(T_SEMICOLON, &ast->semicolon_token);
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseDeclarationStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    int start = cursor();
    DeclarationAST *declaration = nullptr;
    if (! parseBlockDeclaration(declaration))
        return false;

    if (SimpleDeclarationAST *simpleDeclaration = declaration->asSimpleDeclaration()) {
        if (! simpleDeclaration->decl_specifier_list) {
            rewind(start);
            return false;
        }
    }

    DeclarationStatementAST *ast = new (_pool) DeclarationStatementAST;
    ast->declaration = declaration;
    node = ast;
    return true;
}

bool Parser::lookAtCVQualifier() const
{
    switch (LA()) {
    case T_CONST:
    case T_VOLATILE:
        return true;
    default:
        return false;
    }
}

bool Parser::lookAtFunctionSpecifier() const
{
    switch (LA()) {
    case T_INLINE:
    case T_VIRTUAL:
    case T_EXPLICIT:
        return true;
    default:
        return false;
    }
}

bool Parser::lookAtStorageClassSpecifier() const
{
    switch (LA()) {
    case T_FRIEND:
    case T_REGISTER:
    case T_STATIC:
    case T_EXTERN:
    case T_MUTABLE:
    case T_TYPEDEF:
    case T___THREAD:
        return true;
    case T_THREAD_LOCAL:
        return _languageFeatures.cxx11Enabled;
    case T_CONSTEXPR:
        if (_languageFeatures.cxx11Enabled)
            return true;
        Q_FALLTHROUGH();
    default:
        return false;
    }
}

bool Parser::lookAtBuiltinTypeSpecifier() const
{
    switch (LA()) {
    case T_CHAR:
    case T_CHAR16_T:
    case T_CHAR32_T:
    case T_WCHAR_T:
    case T_BOOL:
    case T_SHORT:
    case T_INT:
    case T_LONG:
    case T_SIGNED:
    case T_UNSIGNED:
    case T_FLOAT:
    case T_DOUBLE:
    case T_VOID:
    case T_AUTO:
    case T_DECLTYPE:
        return true;
    // [gcc] extensions
    case T___TYPEOF__:
    case T___ATTRIBUTE__:
    // [msvc] extensions
    case T___DECLSPEC:
        return true;
    default:
        return false;
    }
}

bool Parser::lookAtClassKey() const
{
    switch (LA()) {
    case T_CLASS:
    case T_STRUCT:
    case T_UNION:
        return true;
    default:
        return false;
    }
}

bool Parser::parseOptionalAttributeSpecifierSequence(SpecifierListAST *&attribute_list)
{
    DEBUG_THIS_RULE();
    bool didRead = false;
    while (parseAttributeSpecifier(attribute_list))
        didRead = true;
    return didRead;
}

bool Parser::parseAttributeSpecifier(SpecifierListAST *&attribute_list)
{
    DEBUG_THIS_RULE();
    SpecifierListAST **attr_ptr = &attribute_list;
    switch (LA()) {
    case T_ALIGNAS: {
        AlignmentSpecifierAST *ast = new (_pool) AlignmentSpecifierAST;
        ast->align_token = consumeToken();
        match(T_LPAREN, &ast->lparen_token);

        const int saved = cursor();
        if (!parseTypeId(ast->typeIdExprOrAlignmentExpr) ||
                (LA() != T_RPAREN &&
                (LA(1) != T_DOT_DOT_DOT || LA(2) != T_RPAREN))) {
            rewind(saved);
            parseExpression(ast->typeIdExprOrAlignmentExpr);
        }

        if (LA() == T_DOT_DOT_DOT)
            ast->ellipses_token = consumeToken();
        match(T_RPAREN, &ast->rparen_token);
        attribute_list = new (_pool) SpecifierListAST(ast);
        return true;
    }
        //### TODO: C++11-style attributes
//    case T_LBRACKET:
    case T___ATTRIBUTE__:
        while (LA() == T___ATTRIBUTE__) {
            parseGnuAttributeSpecifier(*attr_ptr);
            attr_ptr = &(*attr_ptr)->next;
        }
        return true;
    case T___DECLSPEC:
        while (LA() == T___DECLSPEC) {
            parseMsvcDeclspecSpecifier(*attr_ptr);
            attr_ptr = &(*attr_ptr)->next;
        }
        return true;
    default:
    {
        bool foundAttributes = false;
        while (lookAtStdAttribute()) {
            parseStdAttributeSpecifier(*attr_ptr);
            attr_ptr = &(*attr_ptr)->next;
            foundAttributes = true;
        }
        return foundAttributes;
    }
    }
}

bool Parser::parseGnuAttributeSpecifier(SpecifierListAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T___ATTRIBUTE__)
        return false;

    GnuAttributeSpecifierAST *ast = new (_pool) GnuAttributeSpecifierAST;
    ast->attribute_token = consumeToken();
    match(T_LPAREN, &ast->first_lparen_token);
    match(T_LPAREN, &ast->second_lparen_token);
    parseGnuAttributeList(ast->attribute_list);
    match(T_RPAREN, &ast->first_rparen_token);
    match(T_RPAREN, &ast->second_rparen_token);
    node = new (_pool) SpecifierListAST(ast);
    return true;
}

bool Parser::parseGnuAttributeList(GnuAttributeListAST *&node)
{
    DEBUG_THIS_RULE();

    GnuAttributeListAST **iter = &node;
    while (LA() == T_CONST || LA() == T_IDENTIFIER) {
        *iter = new (_pool) GnuAttributeListAST;

        if (LA() == T_CONST) {
            GnuAttributeAST *attr = new (_pool) GnuAttributeAST;
            attr->identifier_token = consumeToken();

            (*iter)->value = attr;
            iter = &(*iter)->next;
        } else if (LA() == T_IDENTIFIER) {
            GnuAttributeAST *attr = new (_pool) GnuAttributeAST;
            attr->identifier_token = consumeToken();
            if (LA() == T_LPAREN) {
                attr->lparen_token = consumeToken();
                parseExpressionList(attr->expression_list);
                match(T_RPAREN, &attr->rparen_token);
            }

            (*iter)->value = attr;
            iter = &(*iter)->next;
        }

        if (LA() != T_COMMA)
            break;

        consumeToken(); // skip T_COMMA
    }

    return true;
}

bool Parser::parseMsvcDeclspecSpecifier(SpecifierListAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T___DECLSPEC)
        return false;

    MsvcDeclspecSpecifierAST *ast = new (_pool) MsvcDeclspecSpecifierAST;
    ast->attribute_token = consumeToken();
    match(T_LPAREN, &ast->lparen_token);
    parseGnuAttributeList(ast->attribute_list);
    match(T_RPAREN, &ast->rparen_token);
    node = new (_pool) SpecifierListAST(ast);
    return true;
}

bool Parser::parseStdAttributeSpecifier(SpecifierListAST *&node)
{
    DEBUG_THIS_RULE();
    if (!lookAtStdAttribute())
        return false;

    StdAttributeSpecifierAST *ast = new (_pool) StdAttributeSpecifierAST;
    match(T_LBRACKET, &ast->first_lbracket_token);
    match(T_LBRACKET, &ast->second_lbracket_token);
    parseGnuAttributeList(ast->attribute_list);
    match(T_RBRACKET, &ast->first_rbracket_token);
    match(T_RBRACKET, &ast->second_rbracket_token);
    node = new (_pool) SpecifierListAST(ast);
    return true;
}

bool Parser::parseBuiltinTypeSpecifier(SpecifierListAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T___ATTRIBUTE__) {
        return parseGnuAttributeSpecifier(node);
    } else if (LA() == T___DECLSPEC) {
        return parseMsvcDeclspecSpecifier(node);
    } else if (lookAtStdAttribute()) {
        return parseStdAttributeSpecifier(node);
    } else if (LA() == T___TYPEOF__) {
        TypeofSpecifierAST *ast = new (_pool) TypeofSpecifierAST;
        ast->typeof_token = consumeToken();
        if (LA() == T_LPAREN) {
            int lparen_token = consumeToken();
            if (parseTypeId(ast->expression) && LA() == T_RPAREN) {
                ast->lparen_token = lparen_token;
                ast->rparen_token = consumeToken();
                node = new (_pool) SpecifierListAST(ast);
                return true;
            }
            rewind(lparen_token);
        }
        parseUnaryExpression(ast->expression);
        node = new (_pool) SpecifierListAST(ast);
        return true;
    } else if (LA() == T_DECLTYPE) {
        DecltypeSpecifierAST *ast = new (_pool) DecltypeSpecifierAST;
        ast->decltype_token = consumeToken();
        match(T_LPAREN, &ast->lparen_token);
        if (parseExpression(ast->expression))
            match(T_RPAREN, &ast->rparen_token);
        node = new (_pool) SpecifierListAST(ast);
        return true;
    } else if (lookAtBuiltinTypeSpecifier()) {
        SimpleSpecifierAST *ast = new (_pool) SimpleSpecifierAST;
        ast->specifier_token = consumeToken();
        node = new (_pool) SpecifierListAST(ast);
        return true;
    }
    return false;
}

bool Parser::parseSimpleDeclaration(DeclarationAST *&node, ClassSpecifierAST *declaringClass)
{
    DEBUG_THIS_RULE();
    const ASTCache::CacheKey cacheKey(cursor(), ASTCache::Declaration);
    CHECK_CACHE(cacheKey.astKind, DeclarationAST);

    int qt_invokable_token = 0;
    if (declaringClass && (LA() == T_Q_SIGNAL || LA() == T_Q_SLOT || LA() == T_Q_INVOKABLE))
        qt_invokable_token = consumeToken();

    // parse a simple declaration, a function definition,
    // or a contructor declaration.
    bool has_type_specifier = false;
    bool has_complex_type_specifier = false;
    int startOfNamedTypeSpecifier = 0;
    NameAST *named_type_specifier = nullptr;
    SpecifierListAST *decl_specifier_seq = nullptr,
         **decl_specifier_seq_ptr = &decl_specifier_seq;
    for (;;) {
        if (lookAtCVQualifier() || lookAtFunctionSpecifier()
                || lookAtStorageClassSpecifier()) {
            SimpleSpecifierAST *spec = new (_pool) SimpleSpecifierAST;
            spec->specifier_token = consumeToken();
            *decl_specifier_seq_ptr = new (_pool) SpecifierListAST(spec);
            decl_specifier_seq_ptr = &(*decl_specifier_seq_ptr)->next;
        } else if (parseAttributeSpecifier(*decl_specifier_seq_ptr)) {
            decl_specifier_seq_ptr = &(*decl_specifier_seq_ptr)->next;
        } else if (! named_type_specifier && ! has_complex_type_specifier && lookAtBuiltinTypeSpecifier()) {
            parseBuiltinTypeSpecifier(*decl_specifier_seq_ptr);
            decl_specifier_seq_ptr = &(*decl_specifier_seq_ptr)->next;
            has_type_specifier = true;
        } else if (! has_type_specifier && (LA() == T_COLON_COLON ||
                                            LA() == T_IDENTIFIER)) {
            startOfNamedTypeSpecifier = cursor();
            if (parseName(named_type_specifier)) {

                const Identifier *classIdentifier = className(declaringClass);
                if (QualifiedNameAST *qn = named_type_specifier->asQualifiedName())
                    if (NestedNameSpecifierListAST *namesList = qn->nested_name_specifier_list)
                        if (NestedNameSpecifierAST *lastName = namesList->lastValue())
                            classIdentifier = identifier(lastName->class_or_namespace_name);

                if (LA() == T_LPAREN && identifier(named_type_specifier) == classIdentifier) {
                    // looks like a constructor declaration
                    rewind(startOfNamedTypeSpecifier);
                    break;
                }

                NamedTypeSpecifierAST *spec = new (_pool) NamedTypeSpecifierAST;
                spec->name = named_type_specifier;
                *decl_specifier_seq_ptr = new (_pool) SpecifierListAST(spec);
                decl_specifier_seq_ptr = &(*decl_specifier_seq_ptr)->next;
                has_type_specifier = true;
            } else {
                rewind(startOfNamedTypeSpecifier);
                break;
            }
        } else if (! has_type_specifier && LA() == T_ENUM) {
            int startOfTypeSpecifier = cursor();
            if (! parseElaboratedTypeSpecifier(*decl_specifier_seq_ptr)
                    || LA() == T_LBRACE
                    || (_languageFeatures.cxx11Enabled && LA() == T_COLON)) {
                rewind(startOfTypeSpecifier);
                if (! parseEnumSpecifier(*decl_specifier_seq_ptr)) {
                    error(startOfTypeSpecifier, "expected an enum specifier");
                    break;
                }
                has_complex_type_specifier = true;
            }
            decl_specifier_seq_ptr = &(*decl_specifier_seq_ptr)->next;
            has_type_specifier = true;
        } else if (! has_type_specifier && LA() == T_TYPENAME) {
            int startOfElaboratedTypeSpecifier = cursor();
            if (! parseElaboratedTypeSpecifier(*decl_specifier_seq_ptr)) {
                error(startOfElaboratedTypeSpecifier, "expected an elaborated type specifier");
                break;
            }
            decl_specifier_seq_ptr = &(*decl_specifier_seq_ptr)->next;
            has_type_specifier = true;
        } else if (! has_type_specifier && lookAtClassKey()) {
            int startOfTypeSpecifier = cursor();
            if (! parseElaboratedTypeSpecifier(*decl_specifier_seq_ptr) ||
                (LA() == T_COLON || LA() == T_LBRACE
                 || (LA(0) == T_IDENTIFIER && LA(1) == T_IDENTIFIER // MACRO Name followed by : or {
                     && (LA(2) == T_COLON || LA(2) == T_LBRACE))
                 || (LA(0) == T_IDENTIFIER && LA(1) == T_IDENTIFIER && LA(2) == T_IDENTIFIER && // MACRO Name final followed by : or {
                     (LA(3) == T_COLON || LA(3) == T_LBRACE)))) {
                rewind(startOfTypeSpecifier);
                if (! parseClassSpecifier(*decl_specifier_seq_ptr)) {
                    error(startOfTypeSpecifier, "wrong type specifier");
                    break;
                }
                has_complex_type_specifier = true;
            }
            decl_specifier_seq_ptr = &(*decl_specifier_seq_ptr)->next;
            has_type_specifier = true;
        } else
            break;
    }

    DeclaratorListAST *declarator_list = nullptr,
        **declarator_ptr = &declarator_list;

    DeclaratorAST *declarator = nullptr;

    if (LA() != T_SEMICOLON) {
        const bool maybeCtor = (LA() == T_LPAREN && named_type_specifier);
        bool didParseInitDeclarator = parseInitDeclarator(declarator, decl_specifier_seq, declaringClass);
        if ((! didParseInitDeclarator && maybeCtor) || (didParseInitDeclarator && maybeCtor && LA() == T_COLON)){
            rewind(startOfNamedTypeSpecifier);
            named_type_specifier = nullptr;
            // pop the named type specifier from the decl-specifier-seq
            SpecifierListAST **spec_ptr = &decl_specifier_seq;
            for (; *spec_ptr; spec_ptr = &(*spec_ptr)->next) {
                if (! (*spec_ptr)->next) {
                    *spec_ptr = nullptr;
                    break;
                }
            }
            if (! parseInitDeclarator(declarator, decl_specifier_seq, declaringClass))
                CACHE_AND_RETURN(cacheKey, false);
        }
    }

    // if there is no valid declarator
    // and it doesn't look like a fwd or a class declaration
    // then it's not a declarations
    if (! declarator && ! maybeForwardOrClassDeclaration(decl_specifier_seq))
        CACHE_AND_RETURN(cacheKey, false);

    DeclaratorAST *firstDeclarator = declarator;

    if (declarator) {
        *declarator_ptr = new (_pool) DeclaratorListAST;
        (*declarator_ptr)->value = declarator;
        declarator_ptr = &(*declarator_ptr)->next;
    }

    if (LA() == T_COMMA || LA() == T_SEMICOLON || has_complex_type_specifier) {
        while (LA() == T_COMMA) {
            consumeToken(); // consume T_COMMA

            declarator = nullptr;
            if (parseInitDeclarator(declarator, decl_specifier_seq, declaringClass)) {
                *declarator_ptr = new (_pool) DeclaratorListAST;
                (*declarator_ptr)->value = declarator;
                declarator_ptr = &(*declarator_ptr)->next;
            }
        }
        SimpleDeclarationAST *ast = new (_pool) SimpleDeclarationAST;
        ast->qt_invokable_token = qt_invokable_token;
        ast->decl_specifier_list = decl_specifier_seq;
        ast->declarator_list = declarator_list;
        match(T_SEMICOLON, &ast->semicolon_token);
        node = ast;
        CACHE_AND_RETURN(cacheKey, true);
    } else if (! _inFunctionBody && declarator && (LA() == T_COLON || LA() == T_LBRACE || LA() == T_TRY)) {
        if (LA() == T_TRY) {
            FunctionDefinitionAST *ast = new (_pool) FunctionDefinitionAST;
            ast->qt_invokable_token = qt_invokable_token;
            ast->decl_specifier_list = decl_specifier_seq;
            ast->declarator = firstDeclarator;
            parseTryBlockStatement(ast->function_body, &ast->ctor_initializer);
            node = ast;
            CACHE_AND_RETURN(cacheKey, true); // recognized a function definition.
        } else {
            CtorInitializerAST *ctor_initializer = nullptr;
            bool hasCtorInitializer = false;

            if (LA() == T_COLON) {
                hasCtorInitializer = true;
                parseCtorInitializer(ctor_initializer);

                if (LA() != T_LBRACE) {
                    const int pos = cursor();

                    for (int n = 0; n < 3 && LA(); consumeToken(), ++n)
                        if (LA() == T_LBRACE)
                            break;

                    if (LA() != T_LBRACE) {
                        error(pos, "unexpected token `%s'", _translationUnit->spell(pos));
                        rewind(pos);
                    }
                }
            }

            if (LA() == T_LBRACE || hasCtorInitializer) {
                FunctionDefinitionAST *ast = new (_pool) FunctionDefinitionAST;
                ast->qt_invokable_token = qt_invokable_token;
                ast->decl_specifier_list = decl_specifier_seq;
                ast->declarator = firstDeclarator;
                ast->ctor_initializer = ctor_initializer;
                parseFunctionBody(ast->function_body);
                node = ast;
                CACHE_AND_RETURN(cacheKey, true); // recognized a function definition.
            }
        }
    }

    error(cursor(), "unexpected token `%s'", tok().spell());
    CACHE_AND_RETURN(cacheKey, false);
}

bool Parser::maybeForwardOrClassDeclaration(SpecifierListAST *decl_specifier_seq) const
{
    // look at the decl_specifier for possible fwd or class declarations.
    if (SpecifierListAST *it = decl_specifier_seq) {
        while (it) {
            SimpleSpecifierAST *spec = it->value->asSimpleSpecifier();
            if (spec && _translationUnit->tokenKind(spec->specifier_token) == T_FRIEND)
                it = it->next;
            else
                break;
        }

        if (it) {
            SpecifierAST *spec = it->value;

            if (spec->asElaboratedTypeSpecifier() ||
                    spec->asEnumSpecifier() ||
                    spec->asClassSpecifier()) {
                for (it = it->next; it; it = it->next)
                    if (it->value->asAttributeSpecifier() == nullptr)
                        return false;
                return true;
            }
        }
    }

    return false;
}

bool Parser::parseFunctionBody(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    if (_translationUnit->skipFunctionBody()) {
        int token_lbrace = 0;
        match(T_LBRACE, &token_lbrace);
        if (! token_lbrace)
            return false;

        const Token &tk = _translationUnit->tokenAt(token_lbrace);
        if (tk.close_brace)
            rewind(tk.close_brace);
        int token_rbrace = 0;
        match(T_RBRACE, &token_rbrace);
        return true;
    }

    _inFunctionBody = true;
    const bool parsed = parseCompoundStatement(node);
    _inFunctionBody = false;
    return parsed;
}

/**
 * Parses both try-block and function-try-block
 * @param placeholder Non-null for function-try-block in around constructor
 *
 *  try-block:
 *      try compound-statement handler-seq
 *  function-try-block:
 *      try [ctor-initializer] compound-statement handler-seq
 */
bool Parser::parseTryBlockStatement(StatementAST *&node, CtorInitializerAST **placeholder)
{
    DEBUG_THIS_RULE();

    if (LA() == T_TRY) {
        TryBlockStatementAST *ast = new (_pool) TryBlockStatementAST;
        // try
        ast->try_token = consumeToken();
        // [ctor-initializer]
        if (LA() == T_COLON) {
            const int colonPos = cursor();
            CtorInitializerAST *ctor_initializer = nullptr;
            parseCtorInitializer(ctor_initializer);

            if (LA() != T_LBRACE) {
                const int pos = cursor();

                for (int n = 0; n < 3 && LA(); consumeToken(), ++n)
                    if (LA() == T_LBRACE)
                        break;

                if (LA() != T_LBRACE) {
                    error(pos, "unexpected token `%s'", _translationUnit->spell(pos));
                    rewind(pos);
                }
            }

            if (placeholder)
                *placeholder = ctor_initializer;
            else
                error(colonPos, "constructor initializer not allowed inside function body");
        }
        // compound-statement
        parseCompoundStatement(ast->statement);
        // handler-seq
        CatchClauseListAST **catch_clause_ptr = &ast->catch_clause_list;
        while (parseCatchClause(*catch_clause_ptr))
            catch_clause_ptr = &(*catch_clause_ptr)->next;
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseCatchClause(CatchClauseListAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_CATCH) {
        CatchClauseAST *ast = new (_pool) CatchClauseAST;
        ast->catch_token = consumeToken();
        match(T_LPAREN, &ast->lparen_token);
        parseExceptionDeclaration(ast->exception_declaration);
        match(T_RPAREN, &ast->rparen_token);
        parseCompoundStatement(ast->statement);
        node = new (_pool) CatchClauseListAST(ast);
        return true;
    }
    return false;
}

bool Parser::parseExceptionDeclaration(ExceptionDeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_DOT_DOT_DOT) {
        ExceptionDeclarationAST *ast = new (_pool) ExceptionDeclarationAST;
        ast->dot_dot_dot_token = consumeToken();
        node = ast;
        return true;
    }

    SpecifierListAST *type_specifier = nullptr;
    if (parseTypeSpecifier(type_specifier)) {
        ExceptionDeclarationAST *ast = new (_pool) ExceptionDeclarationAST;
        ast->type_specifier_list = type_specifier;
        parseDeclaratorOrAbstractDeclarator(ast->declarator, type_specifier);
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseBoolLiteral(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_TRUE || LA() == T_FALSE) {
        BoolLiteralAST *ast = new (_pool) BoolLiteralAST;
        ast->literal_token = consumeToken();
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseNumericLiteral(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_NUMERIC_LITERAL  ||
        LA() == T_CHAR_LITERAL     ||
        LA() == T_WIDE_CHAR_LITERAL ||
        LA() == T_UTF16_CHAR_LITERAL ||
        LA() == T_UTF32_CHAR_LITERAL) {
        NumericLiteralAST *ast = new (_pool) NumericLiteralAST;
        ast->literal_token = consumeToken();
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parsePointerLiteral(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_NULLPTR) {
        PointerLiteralAST *ast = new (_pool) PointerLiteralAST;
        ast->literal_token = consumeToken();
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseThisExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_THIS) {
        ThisExpressionAST *ast = new (_pool) ThisExpressionAST;
        ast->this_token = consumeToken();
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parsePrimaryExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    switch (LA()) {
    case T_STRING_LITERAL:
    case T_WIDE_STRING_LITERAL:
    case T_UTF8_STRING_LITERAL:
    case T_UTF16_STRING_LITERAL:
    case T_UTF32_STRING_LITERAL:
    case T_RAW_STRING_LITERAL:
    case T_RAW_WIDE_STRING_LITERAL:
    case T_RAW_UTF8_STRING_LITERAL:
    case T_RAW_UTF16_STRING_LITERAL:
    case T_RAW_UTF32_STRING_LITERAL:
        return parseStringLiteral(node);

    case T_NULLPTR:
        if (_languageFeatures.cxx11Enabled)
            return parsePointerLiteral(node);
        Q_FALLTHROUGH();

    case T_CHAR_LITERAL: // ### FIXME don't use NumericLiteral for chars
    case T_WIDE_CHAR_LITERAL:
    case T_UTF16_CHAR_LITERAL:
    case T_UTF32_CHAR_LITERAL:
    case T_NUMERIC_LITERAL:
        return parseNumericLiteral(node);

    case T_TRUE:
    case T_FALSE:
        return parseBoolLiteral(node);

    case T_THIS:
        return parseThisExpression(node);

    case T_LPAREN:
        if (LA(2) == T_LBRACE) {
            // GNU extension: '(' '{' statement-list '}' ')'
            CompoundExpressionAST *ast = new (_pool) CompoundExpressionAST;
            ast->lparen_token = consumeToken();
            StatementAST *statement = nullptr;
            if (parseCompoundStatement(statement))
                ast->statement = statement->asCompoundStatement();
            match(T_RPAREN, &ast->rparen_token);
            node = ast;
            return true;
        } else {
            return parseNestedExpression(node);
        }

    case T_SIGNAL:
    case T_SLOT:
        return parseQtMethod(node);

    case T_LBRACKET: {
        const int lbracket_token = cursor();

        if (_languageFeatures.cxx11Enabled) {
            if (parseLambdaExpression(node))
                return true;
        }

        if (_languageFeatures.objCEnabled) {
            rewind(lbracket_token);
            return parseObjCExpression(node);
        }
    } break;

    case T_AT_STRING_LITERAL:
    case T_AT_ENCODE:
    case T_AT_PROTOCOL:
    case T_AT_SELECTOR:
        return parseObjCExpression(node);

    case T_REQUIRES:
        return parseRequiresExpression(node);

    default: {
        NameAST *name = nullptr;
        if (parseNameId(name)) {
            IdExpressionAST *ast = new (_pool) IdExpressionAST;
            ast->name = name;
            node = ast;
            return true;
        }
        break;
    } // default

    } // switch

    return false;
}

bool Parser::parseObjCExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    switch (LA()) {
    case T_AT_ENCODE:
        return parseObjCEncodeExpression(node);

    case T_AT_PROTOCOL:
        return parseObjCProtocolExpression(node);

    case T_AT_SELECTOR:
        return parseObjCSelectorExpression(node);

    case T_LBRACKET:
        return parseObjCMessageExpression(node);

    case T_AT_STRING_LITERAL:
        return parseObjCStringLiteral(node);

    default:
        break;
    } // switch
    return false;
}

bool Parser::parseObjCStringLiteral(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_AT_STRING_LITERAL)
        return false;

    StringLiteralAST **ast = reinterpret_cast<StringLiteralAST **> (&node);

    while (LA() == T_AT_STRING_LITERAL) {
        *ast = new (_pool) StringLiteralAST;
        (*ast)->literal_token = consumeToken();
        ast = &(*ast)->next;
    }
    return true;
}

///  objc-try-catch-statement:
///    @try compound-statement objc-catch-list[opt]
///    @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
///  catch-parameter-declaration:
///     parameter-declaration
///     '...' [OBJC2]
///
bool Parser::parseObjCTryStatement(StatementAST *& /*node*/)
{
    DEBUG_THIS_RULE();
    if (LA() != T_AT_TRY)
        return false;

    /*try_token =*/ consumeToken();
    StatementAST *body_statment;
    parseCompoundStatement(body_statment);
    while (LA() == T_AT_CATCH) {
        /*catch_token =*/ consumeToken();
        int lparen_token;
        match(T_LPAREN, &lparen_token);
        if (LA() == T_DOT_DOT_DOT) {
            /*int ellipsis_token =*/ consumeToken();
        } else {
            ParameterDeclarationAST *exception_decl;
            parseParameterDeclaration(exception_decl);
        }
        int rparen_token;
        match(T_RPAREN, &rparen_token);
        StatementAST *catch_statement;
        parseCompoundStatement(catch_statement);
    }

    if (LA() == T_AT_FINALLY) {
        StatementAST *finally_statement;
        parseCompoundStatement(finally_statement);
    }

    return true;
}

/// objc-synchronized-statement:
///   @synchronized expression ;
bool Parser::parseObjCSynchronizedStatement(StatementAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_AT_SYNCHRONIZED)
        return false;

    ObjCSynchronizedStatementAST *ast = new (_pool) ObjCSynchronizedStatementAST;

    ast->synchronized_token = consumeToken();
    match(T_LPAREN, &ast->lparen_token);
    parseExpression(ast->synchronized_object);
    match(T_RPAREN, &ast->rparen_token);
    parseStatement(ast->statement);

    node = ast;
    return true;
}

/// objc-throw-statement:
///   @ throw expression ;
bool Parser::parseObjCThrowStatement(StatementAST *&/*node*/)
{
    DEBUG_THIS_RULE();
    if (LA() != T_AT_THROW)
        return false;

    /*throw_token =*/ consumeToken();
    ExpressionAST *thrown_expression;
    parseExpression(thrown_expression);
    int semicolon_token;
    match(T_SEMICOLON, &semicolon_token);

    return true;
}

bool Parser::parseObjCEncodeExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_AT_ENCODE)
        return false;

    ObjCEncodeExpressionAST *ast = new (_pool) ObjCEncodeExpressionAST;
    ast->encode_token = consumeToken();
    parseObjCTypeName(ast->type_name);
    node = ast;
    return true;
}

bool Parser::parseObjCProtocolExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_AT_PROTOCOL)
        return false;

    ObjCProtocolExpressionAST *ast = new (_pool) ObjCProtocolExpressionAST;
    ast->protocol_token = consumeToken();
    match(T_LPAREN, &ast->lparen_token);
    match(T_IDENTIFIER, &ast->identifier_token);
    match(T_RPAREN, &ast->rparen_token);
    node = ast;
    return true;
}

bool Parser::parseObjCSelectorExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_AT_SELECTOR)
        return false;

    ObjCSelectorExpressionAST *ast = new (_pool) ObjCSelectorExpressionAST;
    ast->selector_token = consumeToken();
    match(T_LPAREN, &ast->lparen_token);

    int identifier_token = 0;
    match(T_IDENTIFIER, &identifier_token);
    if (LA() == T_COLON) {
        ObjCSelectorAST *args = new (_pool) ObjCSelectorAST;
        ast->selector = args;
        ObjCSelectorArgumentListAST *last = new (_pool) ObjCSelectorArgumentListAST;
        args->selector_argument_list = last;
        last->value = new (_pool) ObjCSelectorArgumentAST;
        last->value->name_token = identifier_token;
        last->value->colon_token = consumeToken();

        while (LA(1) == T_IDENTIFIER && LA(2) == T_COLON) {
            last->next = new (_pool) ObjCSelectorArgumentListAST;
            last = last->next;
            last->value = new (_pool) ObjCSelectorArgumentAST;
            last->value->name_token = consumeToken();
            last->value->colon_token = consumeToken();
        }
    } else {
        ObjCSelectorAST *args = new (_pool) ObjCSelectorAST;
        ast->selector = args;
        args->selector_argument_list = new (_pool) ObjCSelectorArgumentListAST;
        args->selector_argument_list->value = new (_pool) ObjCSelectorArgumentAST;
        args->selector_argument_list->value->name_token = identifier_token;
    }

    if (LA(1) == T_IDENTIFIER && LA(2) == T_RPAREN) {
        const char *txt = tok(1).spell();
        consumeToken();
        error(cursor(), "missing ':' after '%s'", txt);
    }
    match(T_RPAREN, &ast->rparen_token);

    node = ast;
    return true;
}

bool Parser::parseObjCMessageExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_LBRACKET)
        return false;

    int start = cursor();

    int lbracket_token = consumeToken();
    ExpressionAST *receiver_expression = nullptr;
    ObjCSelectorAST *selector = nullptr;
    ObjCMessageArgumentListAST *argument_list = nullptr;

    if (parseObjCMessageReceiver(receiver_expression) &&
        parseObjCMessageArguments(selector, argument_list)) {

        ObjCMessageExpressionAST *ast = new (_pool) ObjCMessageExpressionAST;
        ast->lbracket_token = lbracket_token;
        ast->receiver_expression = receiver_expression;
        ast->selector = selector;
        ast->argument_list = argument_list;

        match(T_RBRACKET, &ast->rbracket_token);
        node = ast;

        return true;
    }

    rewind(start);
    return false;
}

bool Parser::parseObjCMessageReceiver(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    return parseExpression(node);
}

bool Parser::parseObjCMessageArguments(ObjCSelectorAST *&selNode, ObjCMessageArgumentListAST *& argNode)
{
    DEBUG_THIS_RULE();
    if (LA() == T_RBRACKET)
        return false; // nothing to do.

    int start = cursor();

    ObjCSelectorArgumentAST *selectorArgument = nullptr;
    ObjCMessageArgumentAST *messageArgument = nullptr;

    if (parseObjCSelectorArg(selectorArgument, messageArgument)) {
        ObjCSelectorArgumentListAST *selAst = new (_pool) ObjCSelectorArgumentListAST;
        selAst->value = selectorArgument;
        ObjCSelectorArgumentListAST *lastSelector = selAst;

        ObjCMessageArgumentListAST *argAst = new (_pool) ObjCMessageArgumentListAST;
        argAst->value = messageArgument;
        ObjCMessageArgumentListAST *lastArgument = argAst;

        while (parseObjCSelectorArg(selectorArgument, messageArgument)) {
            // accept the selector args.
            lastSelector->next = new (_pool) ObjCSelectorArgumentListAST;
            lastSelector = lastSelector->next;
            lastSelector->value = selectorArgument;

            lastArgument->next = new (_pool) ObjCMessageArgumentListAST;
            lastArgument = lastArgument->next;
            lastArgument->value = messageArgument;
        }

        if (LA() == T_COMMA) {
            ExpressionAST **lastExpression = &lastArgument->value->parameter_value_expression;

            while (LA() == T_COMMA) {
                BinaryExpressionAST *binaryExpression = new (_pool) BinaryExpressionAST;
                binaryExpression->left_expression = *lastExpression;
                binaryExpression->binary_op_token = consumeToken(); // T_COMMA
                parseAssignmentExpression(binaryExpression->right_expression);
                lastExpression = &binaryExpression->right_expression;
            }
        }

        ObjCSelectorAST *selWithArgs = new (_pool) ObjCSelectorAST;
        selWithArgs->selector_argument_list = selAst;

        selNode = selWithArgs;
        argNode = argAst;
        return true;
    } else {
        rewind(start);
        int name_token = 0;
        if (!parseObjCSelector(name_token))
            return false;
        ObjCSelectorAST *sel = new (_pool) ObjCSelectorAST;
        sel->selector_argument_list = new (_pool) ObjCSelectorArgumentListAST;
        sel->selector_argument_list->value = new (_pool) ObjCSelectorArgumentAST;
        sel->selector_argument_list->value->name_token = name_token;
        selNode = sel;
        argNode = nullptr;
        return true;
    }

    return false;
}

bool Parser::parseObjCSelectorArg(ObjCSelectorArgumentAST *&selNode, ObjCMessageArgumentAST *&argNode)
{
    DEBUG_THIS_RULE();
    int selector_token = 0;
    if (!parseObjCSelector(selector_token))
        return false;

    if (LA() != T_COLON)
        return false;

    selNode = new (_pool) ObjCSelectorArgumentAST;
    selNode->name_token = selector_token;
    selNode->colon_token = consumeToken();

    argNode = new (_pool) ObjCMessageArgumentAST;
    ExpressionAST **expr = &argNode->parameter_value_expression;
    int expressionStart = cursor();
    if (parseAssignmentExpression(*expr) && LA() == T_COLON && (*expr)->asCastExpression()) {
        rewind(expressionStart);
        parseUnaryExpression(*expr);
        //
    }
    return true;
}

bool Parser::parseNameId(NameAST *&name)
{
    DEBUG_THIS_RULE();
    int start = cursor();
    if (! parseName(name))
        return false;

    if (LA() == T_RPAREN || LA() == T_COMMA)
        return true;

    QualifiedNameAST *qualified_name_id = name->asQualifiedName();

    TemplateIdAST *template_id = nullptr;
    if (qualified_name_id) {
        if (NameAST *unqualified_name = qualified_name_id->unqualified_name)
            template_id = unqualified_name->asTemplateId();
    } else {
        template_id = name->asTemplateId();
    }

    if (! template_id)
        return true; // it's not a template-id, there's nothing to rewind.

    else if (LA() == T_LPAREN) {
        // a template-id followed by a T_LPAREN
        if (ExpressionListAST *template_arguments = template_id->template_argument_list) {
            if (! template_arguments->next && template_arguments->value &&
                    template_arguments->value->asBinaryExpression()) {

                int saved = cursor();
                ExpressionAST *expr = nullptr;

                bool blocked = blockErrors(true);
                bool lookAtCastExpression = parseCastExpression(expr);
                (void) blockErrors(blocked);

                if (lookAtCastExpression) {
                    if (CastExpressionAST *cast_expression = expr->asCastExpression()) {
                        if (cast_expression->lparen_token && cast_expression->rparen_token
                                && cast_expression->type_id && cast_expression->expression) {
                            rewind(start);

                            name = nullptr;
                            return parseName(name, false);
                        }
                    }
                }
                rewind(saved);
            }
        }
    }

    switch (LA()) {
    case T_COMMA:
    case T_SEMICOLON:
    case T_LBRACKET:
    case T_LPAREN:
    case T_LBRACE:
        return true;

    case T_THIS:
    case T_IDENTIFIER:
    case T_STATIC_CAST:
    case T_DYNAMIC_CAST:
    case T_REINTERPRET_CAST:
    case T_CONST_CAST:
        rewind(start);
        return parseName(name, false);
    } // switch

    return true;
}

bool Parser::parseNestedExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_LPAREN) {
        int lparen_token = consumeToken();
        bool previousTemplateArguments = switchTemplateArguments(false);

        ExpressionAST *expression = nullptr;
        if (parseExpression(expression) && LA() == T_RPAREN) {
            NestedExpressionAST *ast = new (_pool) NestedExpressionAST;
            ast->lparen_token = lparen_token;
            ast->expression = expression;
            ast->rparen_token = consumeToken();
            node = ast;
            (void) switchTemplateArguments(previousTemplateArguments);
            return true;
        }
        (void) switchTemplateArguments(previousTemplateArguments);
    }
    return false;
}

bool Parser::parseCppCastExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_DYNAMIC_CAST     || LA() == T_STATIC_CAST ||
        LA() == T_REINTERPRET_CAST || LA() == T_CONST_CAST) {
        CppCastExpressionAST *ast = new (_pool) CppCastExpressionAST;
        ast->cast_token = consumeToken();
        match(T_LESS, &ast->less_token);
        parseTypeId(ast->type_id);
        match(T_GREATER, &ast->greater_token);
        match(T_LPAREN, &ast->lparen_token);
        parseExpression(ast->expression);
        match(T_RPAREN, &ast->rparen_token);
        node = ast;
        return true;
    }
    return false;
}

// typename ::opt  nested-name-specifier identifier ( expression-listopt )
// typename ::opt  nested-name-specifier templateopt  template-id ( expression-listopt )
bool Parser::parseTypenameCallExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_TYPENAME) {
        int typename_token = consumeToken();
        NameAST *name = nullptr;
        if (parseName(name)
                && (LA() == T_LPAREN || (_languageFeatures.cxx11Enabled && LA() == T_LBRACE))) {
            TypenameCallExpressionAST *ast = new (_pool) TypenameCallExpressionAST;
            ast->typename_token = typename_token;
            ast->name = name;
            if (LA() == T_LPAREN) {
                parseExpressionListParen(ast->expression);
            } else { // T_LBRACE
                parseBracedInitList0x(ast->expression);
            }
            node = ast;
            return true;
        }
    }
    return false;
}

// typeid ( expression )
// typeid ( type-id )
bool Parser::parseTypeidExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_TYPEID) {
        TypeidExpressionAST *ast = new (_pool) TypeidExpressionAST;
        ast->typeid_token = consumeToken();
        if (LA() == T_LPAREN)
            ast->lparen_token = consumeToken();
        int saved = cursor();
        if (! (parseTypeId(ast->expression) && LA() == T_RPAREN)) {
            rewind(saved);
            parseExpression(ast->expression);
        }
        match(T_RPAREN, &ast->rparen_token);
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseCorePostfixExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();

    switch (LA()) {
    case T_DYNAMIC_CAST:
    case T_STATIC_CAST:
    case T_REINTERPRET_CAST:
    case T_CONST_CAST:
        return parseCppCastExpression(node);

    case T_TYPENAME:
        return parseTypenameCallExpression(node);

    case T_TYPEID:
        return parseTypeidExpression(node);

    default: {
        int start = cursor();
        SpecifierListAST *type_specifier = nullptr;
        bool blocked = blockErrors(true);
        if (lookAtBuiltinTypeSpecifier() &&
                parseSimpleTypeSpecifier(type_specifier) &&
                (LA() == T_LPAREN || (_languageFeatures.cxx11Enabled && LA() == T_LBRACE))) {
            ExpressionAST *expr = nullptr;
            if (LA() == T_LPAREN) {
                parseExpressionListParen(expr);
            } else { // T_LBRACE
                parseBracedInitList0x(expr);
            }
            TypeConstructorCallAST *ast = new (_pool) TypeConstructorCallAST;
            ast->type_specifier_list = type_specifier;
            ast->expression = expr;
            node = ast;
            blockErrors(blocked);
            return true;
        }
        rewind(start);

        // look for compound literals
        if (LA() == T_LPAREN) {
            int lparen_token = consumeToken();
            ExpressionAST *type_id = nullptr;
            if (parseTypeId(type_id) && LA() == T_RPAREN) {
                int rparen_token = consumeToken();
                if (LA() == T_LBRACE) {
                    blockErrors(blocked);

                    CompoundLiteralAST *ast = new (_pool) CompoundLiteralAST;
                    ast->lparen_token = lparen_token;
                    ast->type_id = type_id;
                    ast->rparen_token = rparen_token;
                    parseInitializerClause(ast->initializer);
                    node = ast;
                    return true;
                }
            }
            rewind(start);
        }

        blockErrors(blocked);
        return parsePrimaryExpression(node);
    } // default
    } // switch
}

bool Parser::parsePostfixExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (parseCorePostfixExpression(node)) {
        while (LA()) {
            if (LA() == T_LPAREN) {
                CallAST *ast = new (_pool) CallAST;
                ast->lparen_token = consumeToken();
                parseExpressionList(ast->expression_list);
                match(T_RPAREN, &ast->rparen_token);
                ast->base_expression = node;
                node = ast;
            } else if (LA() == T_LBRACKET) {
                ArrayAccessAST *ast = new (_pool) ArrayAccessAST;
                ast->lbracket_token = consumeToken();
                parseExpression(ast->expression);
                match(T_RBRACKET, &ast->rbracket_token);
                ast->base_expression = node;
                node = ast;
            } else if (_languageFeatures.cxx11Enabled && LA() == T_LBRACE && node->asIdExpression()) {
                // this is slightly inconsistent: simple-type-specifier '(' expression-list ')'
                // gets parsed as a CallAST while simple-type-specifier brace-init-list
                // is a TypenameCallExpressionAST
                TypenameCallExpressionAST *ast = new (_pool) TypenameCallExpressionAST;
                ast->name = node->asIdExpression()->name;
                parseBracedInitList0x(ast->expression);
                node = ast;
            } else if (LA() == T_PLUS_PLUS || LA() == T_MINUS_MINUS) {
                PostIncrDecrAST *ast = new (_pool) PostIncrDecrAST;
                ast->incr_decr_token = consumeToken();
                ast->base_expression = node;
                node = ast;
            } else if (LA() == T_DOT || LA() == T_ARROW) {
                MemberAccessAST *ast = new (_pool) MemberAccessAST;
                ast->access_token = consumeToken();
                if (LA() == T_TEMPLATE)
                    ast->template_token = consumeToken();
                if (! parseNameId(ast->member_name))
                    error(cursor(), "expected unqualified-id before token `%s'", tok().spell());
                ast->base_expression = node;
                node = ast;
            } else break;
        } // while

        return true;
    }
    return false;
}

bool Parser::parseUnaryExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    switch (LA()) {
    case T_PLUS_PLUS:
    case T_MINUS_MINUS:
    case T_STAR:
    case T_AMPER:
    case T_PLUS:
    case T_MINUS:
    case T_EXCLAIM: {
        int op = cursor();
        UnaryExpressionAST *ast = new (_pool) UnaryExpressionAST;
        ast->unary_op_token = consumeToken();
        if (! parseCastExpression(ast->expression))
            error(op, "expected expression after token `%s'", _translationUnit->spell(op));
        node = ast;
        return true;
    }

    case T_TILDE: {
        if (LA(2) == T_IDENTIFIER && LA(3) == T_LPAREN)
            break; // prefer destructor names

        UnaryExpressionAST *ast = new (_pool) UnaryExpressionAST;
        ast->unary_op_token = consumeToken();
        (void) parseCastExpression(ast->expression);
        node = ast;
        return true;
    }

    case T_SIZEOF: {
        SizeofExpressionAST *ast = new (_pool) SizeofExpressionAST;
        ast->sizeof_token = consumeToken();

        // sizeof...(Args)
        if (_languageFeatures.cxx11Enabled && LA() == T_DOT_DOT_DOT && (LA(2) == T_IDENTIFIER || (LA(2) == T_LPAREN && LA(3) == T_IDENTIFIER
                                                                                 && LA(4) == T_RPAREN)))
            ast->dot_dot_dot_token = consumeToken();

        if (LA() == T_LPAREN) {
            int lparen_token = consumeToken();
            const bool blocked = blockErrors(true);
            const bool hasTypeId = parseTypeId(ast->expression);
            (void) blockErrors(blocked);
            if (hasTypeId && LA() == T_RPAREN) {
                ast->lparen_token = lparen_token;
                ast->rparen_token = consumeToken();
                node = ast;
                return true;
            } else {
                rewind(lparen_token);
            }
        }

        parseUnaryExpression(ast->expression);

        node = ast;
        return true;
    }

    case T_ALIGNOF: {
        if (!_languageFeatures.cxx11Enabled)
            break;

        AlignofExpressionAST *ast = new (_pool) AlignofExpressionAST;
        ast->alignof_token = consumeToken();

        match(T_LPAREN, &ast->lparen_token);
        ExpressionAST *temp = nullptr;
        parseTypeId(temp);
        if (temp)
            ast->typeId = temp->asTypeId();
        match(T_RPAREN, &ast->rparen_token);

        node = ast;
        return true;
    }


    case T_NOEXCEPT: {
        if (!_languageFeatures.cxx11Enabled)
            break;

        return parseNoExceptOperatorExpression(node);
    }

    case T_CO_AWAIT:
        if (!_languageFeatures.cxx20Enabled)
            break;
        return parseAwaitExpression(node);

    default:
        break;
    } // switch

    if (LA() == T_NEW || (LA(1) == T_COLON_COLON &&
                          LA(2) == T_NEW))
        return parseNewExpression(node);
    else if (LA() == T_DELETE || (LA(1) == T_COLON_COLON &&
                                  LA(2) == T_DELETE))
        return parseDeleteExpression(node);
    else
        return parsePostfixExpression(node);
}

// new-placement ::= T_LPAREN expression-list T_RPAREN
bool Parser::parseExpressionListParen(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_LPAREN) {
        int lparen_token = consumeToken();
        ExpressionListAST *expression_list = nullptr;
        if (parseExpressionList(expression_list) && LA() == T_RPAREN) {
            int rparen_token = consumeToken();
            ExpressionListParenAST *ast = new (_pool) ExpressionListParenAST;
            ast->lparen_token = lparen_token;
            ast->expression_list = expression_list;
            ast->rparen_token = rparen_token;
            node = ast;
            return true;
        }
    }

    return false;
}


// new-expression ::= T_COLON_COLON? T_NEW new-placement.opt
//                    new-type-id new-initializer.opt
// new-expression ::= T_COLON_COLON? T_NEW new-placement.opt
//                    T_LPAREN type-id T_RPAREN new-initializer.opt
bool Parser::parseNewExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (! (LA() == T_NEW || (LA() == T_COLON_COLON && LA(2) == T_NEW)))
        return false;

    NewExpressionAST *ast = new (_pool) NewExpressionAST;
    if (LA() == T_COLON_COLON)
        ast->scope_token = consumeToken();

    ast->new_token = consumeToken();

    ExpressionAST *parenExpressionList = nullptr;

    if (parseExpressionListParen(parenExpressionList)) {
        int after_new_placement = cursor();

        NewTypeIdAST *new_type_id = nullptr;
        if (parseNewTypeId(new_type_id)) {
            ast->new_placement = parenExpressionList->asExpressionListParen();
            ast->new_type_id = new_type_id;
            parseNewInitializer(ast->new_initializer);
            // recognized new-placement.opt new-type-id new-initializer.opt
            node = ast;
            return true;
        }

        rewind(after_new_placement);
        if (LA() == T_LPAREN) {
            int lparen_token = consumeToken();
            ExpressionAST *type_id = nullptr;
            if (parseTypeId(type_id) && LA() == T_RPAREN) {
                ast->new_placement = parenExpressionList->asExpressionListParen();
                ast->lparen_token = lparen_token;
                ast->type_id = type_id;
                ast->rparen_token = consumeToken();
                parseNewInitializer(ast->new_initializer);
                node = ast;
                return true;
            }
        }
    }

    rewind(ast->new_token + 1);

    if (LA() == T_LPAREN) {
        int lparen_token = consumeToken();
        ExpressionAST *type_id = nullptr;
        if (parseTypeId(type_id) && LA() == T_RPAREN) {
            ast->lparen_token = lparen_token;
            ast->type_id = type_id;
            ast->rparen_token = consumeToken();
            parseNewInitializer(ast->new_initializer);
            node = ast;
            return true;
        }
    }

    parseNewTypeId(ast->new_type_id);
    parseNewInitializer(ast->new_initializer);
    node = ast;
    return true;
}

bool Parser::parseNewTypeId(NewTypeIdAST *&node)
{
    DEBUG_THIS_RULE();
    SpecifierListAST *typeSpec = nullptr;
    if (! parseTypeSpecifier(typeSpec))
        return false;

    NewTypeIdAST *ast = new (_pool) NewTypeIdAST;
    ast->type_specifier_list = typeSpec;

    PtrOperatorListAST **ptrop_it = &ast->ptr_operator_list;
    while (parsePtrOperator(*ptrop_it))
        ptrop_it = &(*ptrop_it)->next;

    NewArrayDeclaratorListAST **it = &ast->new_array_declarator_list;
    while (parseNewArrayDeclarator(*it))
        it = &(*it)->next;

    node = ast;
    return true;
}


bool Parser::parseNewArrayDeclarator(NewArrayDeclaratorListAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_LBRACKET)
        return false;

    NewArrayDeclaratorAST *ast = new (_pool) NewArrayDeclaratorAST;
    ast->lbracket_token = consumeToken();
    parseExpression(ast->expression);
    match(T_RBRACKET, &ast->rbracket_token);

    node = new (_pool) NewArrayDeclaratorListAST;
    node->value = ast;
    return true;
}

bool Parser::parseNewInitializer(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_LPAREN)
        return parseExpressionListParen(node);
    else if (_languageFeatures.cxx11Enabled && LA() == T_LBRACE)
        return parseBracedInitList0x(node);
    return false;
}

bool Parser::parseDeleteExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_DELETE || (LA() == T_COLON_COLON && LA(2) == T_DELETE)) {
        DeleteExpressionAST *ast = new (_pool) DeleteExpressionAST;

        if (LA() == T_COLON_COLON)
            ast->scope_token = consumeToken();

        ast->delete_token = consumeToken();

        if (LA() == T_LBRACKET) {
            ast->lbracket_token = consumeToken();
            match(T_RBRACKET, &ast->rbracket_token);
        }

        (void) parseCastExpression(ast->expression);
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseCastExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_LPAREN) {
        int lparen_token = consumeToken();
        int initialCursor = cursor();
        ExpressionAST *type_id = nullptr;
        if (parseTypeId(type_id) && LA() == T_RPAREN) {

            if (TypeIdAST *tid = type_id->asTypeId()) {
                if (tid->type_specifier_list && ! tid->type_specifier_list->next) {
                    if (tid->type_specifier_list->value->asNamedTypeSpecifier()) {
                        switch (LA(2)) {
                        case T_LBRACKET: // ... it's definitely a unary expression followed by an array access.
                            goto parse_as_unary_expression;

                        case T_PLUS_PLUS:
                        case T_MINUS_MINUS: {
                            const int rparen_token = consumeToken();

                            const bool blocked = blockErrors(true);
                            ExpressionAST *unary = nullptr;
                            bool followedByUnaryExpression = parseUnaryExpression(unary);
                            blockErrors(blocked);
                            rewind(rparen_token);

                            if (followedByUnaryExpression) {
                                if (! unary)
                                    followedByUnaryExpression = false;
                                else if (UnaryExpressionAST *u = unary->asUnaryExpression())
                                    followedByUnaryExpression = u->expression != nullptr;
                            }

                            if (! followedByUnaryExpression)
                                goto parse_as_unary_expression;

                        }   break;

                        case T_LPAREN: // .. it can be parsed as a function call.
                            // ### TODO: check if it is followed by a parenthesized expression list.
                            break;
                        }
                    }
                }
            }

            int rparen_token = consumeToken();
            ExpressionAST *expression = nullptr;
            if (parseCastExpression(expression)) {
                CastExpressionAST *ast = new (_pool) CastExpressionAST;
                ast->lparen_token = lparen_token;
                ast->type_id = type_id;
                ast->rparen_token = rparen_token;
                ast->expression = expression;
                node = ast;
                return true;
            }
        }

parse_as_unary_expression:
        _astCache->insert(ASTCache::TypeId, initialCursor, nullptr, cursor(), false);
        rewind(lparen_token);
    }

    return parseUnaryExpression(node);
}

bool Parser::parseLogicalOrExpression(ExpressionAST *&node)
{
    PARSE_EXPRESSION_WITH_OPERATOR_PRECEDENCE(node, Prec::LogicalOr)
}

bool Parser::parseConditionalExpression(ExpressionAST *&node)
{
    PARSE_EXPRESSION_WITH_OPERATOR_PRECEDENCE(node, Prec::Conditional)
}

bool Parser::parseAssignmentExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_THROW)
        return parseThrowExpression(node);
    else if (LA() == T_CO_YIELD)
        return parseYieldExpression(node);
    else
        PARSE_EXPRESSION_WITH_OPERATOR_PRECEDENCE(node, Prec::Assignment)
}

bool Parser::parseQtMethod(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_SIGNAL || LA() == T_SLOT) {
        QtMethodAST *ast = new (_pool) QtMethodAST;
        ast->method_token = consumeToken();
        match(T_LPAREN, &ast->lparen_token);
        if (! parseDeclarator(ast->declarator, /*decl_specifier_seq =*/ nullptr))
            error(cursor(), "expected a function declarator before token `%s'", tok().spell());
        match(T_RPAREN, &ast->rparen_token);
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseConstantExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    return parseConditionalExpression(node);
}

bool Parser::parseExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    CHECK_CACHE(ASTCache::Expression, ExpressionAST);
    int initialCursor = cursor();

    if (_expressionDepth > MAX_EXPRESSION_DEPTH)
        return false;

    ++_expressionDepth;
    bool success = parseCommaExpression(node);
    --_expressionDepth;

    _astCache->insert(ASTCache::Expression, initialCursor, node, cursor(), success);
    return success;
}

void Parser::parseExpressionWithOperatorPrecedence(ExpressionAST *&lhs, int minPrecedence)
{
    DEBUG_THIS_RULE();

    int iterations = 0;
    while (precedence(tok().kind(), _templateArguments) >= minPrecedence) {
        if (++iterations > MAX_EXPRESSION_DEPTH) {
            warning(cursor(), "Reached parse limit for expression");
            return;
        }

        const int operPrecedence = precedence(tok().kind(), _templateArguments);
        const int oper = consumeToken();

        ConditionalExpressionAST *condExpr = nullptr;
        if (operPrecedence == Prec::Conditional) {
            condExpr = new (_pool) ConditionalExpressionAST;
            condExpr->question_token = oper;
            if (tok().kind() == T_COLON) {
                // GNU extension:
                //   logical-or-expression '?' ':' conditional-expression
                condExpr->left_expression = nullptr;
            } else {
                parseExpression(condExpr->left_expression);
            }
            match(T_COLON, &condExpr->colon_token);
        }

        ExpressionAST *rhs = nullptr;
        const bool isCPlusPlus = true;
        if (operPrecedence <= Prec::Conditional && isCPlusPlus) {
            // in C++ you can put a throw in the right-most expression of a conditional expression,
            // or an assignment, so some special handling:
            if (_languageFeatures.cxx11Enabled) {
                if (!parseInitializerClause0x(rhs))
                    return;
            } else {
                if (!parseAssignmentExpression(rhs))
                    return;
            }
        } else {
            // for C & all other expressions:
            if (!parseCastExpression(rhs))
                return;
        }

        for (int tokenKindAhead = tok().kind(), precedenceAhead = precedence(tokenKindAhead, _templateArguments);
                (precedenceAhead > operPrecedence && isBinaryOperator(tokenKindAhead))
                        || (precedenceAhead == operPrecedence && isRightAssociative(tokenKindAhead));
                tokenKindAhead = tok().kind(), precedenceAhead = precedence(tokenKindAhead, _templateArguments)) {
            parseExpressionWithOperatorPrecedence(rhs, precedenceAhead);
        }

        if (condExpr) { // we were parsing a ternairy conditional expression
            condExpr->condition = lhs;
            condExpr->right_expression = rhs;
            lhs = condExpr;
        } else {
            BinaryExpressionAST *expr = new (_pool) BinaryExpressionAST;
            expr->left_expression = lhs;
            expr->binary_op_token = oper;
            expr->right_expression = rhs;
            lhs = expr;
        }
    }
}

bool Parser::parseCommaExpression(ExpressionAST *&node)
{
    PARSE_EXPRESSION_WITH_OPERATOR_PRECEDENCE(node, Prec::Comma)
}

bool Parser::parseThrowExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() == T_THROW) {
        ThrowExpressionAST *ast = new (_pool) ThrowExpressionAST;
        ast->throw_token = consumeToken();
        parseAssignmentExpression(ast->expression);
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseYieldExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_CO_YIELD)
        return false;
    const auto ast = new (_pool) YieldExpressionAST;
    ast->yield_token = consumeToken();
    if (parseBracedInitList0x(ast->expression) || parseAssignmentExpression(ast->expression)) {
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseAwaitExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_CO_AWAIT)
        return false;
    const auto ast = new (_pool) AwaitExpressionAST;
    ast->await_token = consumeToken();
    if (parseCastExpression(ast->castExpression)) {
        node = ast;
        return true;
    }
    return false;
}

bool Parser::parseNoExceptOperatorExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (_languageFeatures.cxx11Enabled && LA() == T_NOEXCEPT) {
        NoExceptOperatorExpressionAST *ast = new (_pool) NoExceptOperatorExpressionAST;
        ast->noexcept_token = consumeToken();
        parseExpression(ast->expression);
        node = ast;
        return true;
    }
    return false;
}

bool Parser::lookAtStdAttribute() const
{
    return _languageFeatures.cxx11Enabled && LA() == T_LBRACKET && LA(2) == T_LBRACKET;
}

bool Parser::lookAtObjCSelector() const
{
    switch (LA()) {
    case T_IDENTIFIER:
    case T_OR:
    case T_AND:
    case T_NOT:
    case T_XOR:
    case T_BITOR:
    case T_COMPL:
    case T_OR_EQ:
    case T_AND_EQ:
    case T_BITAND:
    case T_NOT_EQ:
    case T_XOR_EQ:
        return true;

    default:
        if (tok().isKeyword())
            return true;
    } // switch

    return false;
}

// designated-initializer ::= designator* T_EQUAL initializer-clause
//
bool Parser::parseDesignatedInitializer(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();
    if (!_languageFeatures.c99Enabled || (LA() != T_DOT && LA() != T_LBRACKET))
        return false;

    DesignatedInitializerAST *ast = new (_pool) DesignatedInitializerAST;
    DesignatorListAST **designator_list_ptr = &ast->designator_list;
    DesignatorAST *designator = nullptr;
    const int start = cursor();
    while (parseDesignator(designator)) {
        *designator_list_ptr = new (_pool) DesignatorListAST;
        (*designator_list_ptr)->value = designator;
        designator_list_ptr = &(*designator_list_ptr)->next;
    }
    if (start == cursor())
        return false;

    if (LA() == T_EQUAL) {
        ast->equal_token = consumeToken();

        if (LA() == T_LBRACE) {
            if (parseBracedInitList0x(node)) {
                node = ast;
                return true;
            }
        } else if (parseAssignmentExpression(ast->initializer)) {
            node = ast;
            return true;
        }
    }

    rewind(start);
    return false;
}

// designator ::= T_DOT T_IDENTIFIER
//                T_LBRACKET constant-expression T_BRACKET
//
bool Parser::parseDesignator(DesignatorAST *&node)
{
    DEBUG_THIS_RULE();
    const int start = cursor();
    if (LA() == T_DOT) {
        DotDesignatorAST *ast = new (_pool) DotDesignatorAST;
        ast->dot_token = consumeToken();
        match(T_IDENTIFIER, &ast->identifier_token);
        node = ast;
        return true;
    } else if (LA() == T_LBRACKET) {
        BracketDesignatorAST *ast = new (_pool) BracketDesignatorAST;
        ast->lbracket_token = consumeToken();
        if (parseConditionalExpression(ast->expression)) {
            match(T_RBRACKET, &ast->rbracket_token);
            node = ast;
            return true;
        }
    }

    rewind(start);
    return false;
}

// objc-class-declaraton ::= T_AT_CLASS (T_IDENTIFIER @ T_COMMA) T_SEMICOLON
//
bool Parser::parseObjCClassForwardDeclaration(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_AT_CLASS)
        return false;

    ObjCClassForwardDeclarationAST *ast = new (_pool) ObjCClassForwardDeclarationAST;

    ast->class_token = consumeToken();
    int identifier_token = 0;
    match(T_IDENTIFIER, &identifier_token);

    ast->identifier_list = new (_pool) NameListAST;
    SimpleNameAST *name = new (_pool) SimpleNameAST;
    name->identifier_token = identifier_token;
    ast->identifier_list->value = name;
    NameListAST **nextId = &ast->identifier_list->next;

    while (LA() == T_COMMA) {
        consumeToken(); // consume T_COMMA
        match(T_IDENTIFIER, &identifier_token);

        *nextId = new (_pool) NameListAST;
        name = new (_pool) SimpleNameAST;
        name->identifier_token = identifier_token;
        (*nextId)->value = name;
        nextId = &(*nextId)->next;
    }

    match(T_SEMICOLON, &ast->semicolon_token);
    node = ast;
    return true;
}

// objc-interface ::= attribute-specifier-list-opt objc-class-interface
// objc-interface ::= objc-category-interface
//
// objc-class-interface ::= T_AT_INTERFACE T_IDENTIFIER (T_COLON T_IDENTIFIER)?
//                          objc-protocol-refs-opt
//                          objc-class-instance-variables-opt
//                          objc-interface-declaration-list
//                          T_AT_END
//
// objc-category-interface ::= T_AT_INTERFACE T_IDENTIFIER
//                             T_LPAREN T_IDENTIFIER? T_RPAREN
//                             objc-protocol-refs-opt
//                             objc-interface-declaration-list
//                             T_AT_END
//
bool Parser::parseObjCInterface(DeclarationAST *&node,
                                SpecifierListAST *attributes)
{
    DEBUG_THIS_RULE();
    if (! attributes && LA() == T___ATTRIBUTE__) {
        SpecifierListAST **attr = &attributes;
        while (parseGnuAttributeSpecifier(*attr))
            attr = &(*attr)->next;
    }

    if (LA() != T_AT_INTERFACE)
        return false;

    int objc_interface_token = consumeToken();
    int identifier_token = 0;
    match(T_IDENTIFIER, &identifier_token);

    if (LA() == T_LPAREN) {
        // a category interface

        if (attributes)
            error(attributes->firstToken(), "invalid attributes for category interface declaration");

        ObjCClassDeclarationAST *ast = new (_pool) ObjCClassDeclarationAST;
        ast->attribute_list = attributes;
        ast->interface_token = objc_interface_token;
        SimpleNameAST *class_name = new (_pool) SimpleNameAST;
        class_name->identifier_token= identifier_token;
        ast->class_name = class_name;

        match(T_LPAREN, &ast->lparen_token);
        if (LA() == T_IDENTIFIER) {
            SimpleNameAST *category_name = new (_pool) SimpleNameAST;
            category_name->identifier_token = consumeToken();
            ast->category_name = category_name;
        }

        match(T_RPAREN, &ast->rparen_token);

        parseObjCProtocolRefs(ast->protocol_refs);

        DeclarationListAST **nextMembers = &ast->member_declaration_list;
        DeclarationAST *declaration = nullptr;
        while (parseObjCInterfaceMemberDeclaration(declaration)) {
            *nextMembers = new (_pool) DeclarationListAST;
            (*nextMembers)->value = declaration;
            nextMembers = &(*nextMembers)->next;
        }

        match(T_AT_END, &ast->end_token);

        node = ast;
        return true;
    } else {
        // a class interface declaration
        ObjCClassDeclarationAST *ast = new (_pool) ObjCClassDeclarationAST;
        ast->attribute_list = attributes;
        ast->interface_token = objc_interface_token;
        SimpleNameAST* class_name = new (_pool) SimpleNameAST;
        class_name->identifier_token = identifier_token;
        ast->class_name = class_name;

        if (LA() == T_COLON) {
            ast->colon_token = consumeToken();
            SimpleNameAST *superclass = new (_pool) SimpleNameAST;
            match(T_IDENTIFIER, &superclass->identifier_token);
            ast->superclass = superclass;
        }

        parseObjCProtocolRefs(ast->protocol_refs);
        parseObjClassInstanceVariables(ast->inst_vars_decl);

        DeclarationListAST **nextMembers = &ast->member_declaration_list;
        DeclarationAST *declaration = nullptr;
        while (parseObjCInterfaceMemberDeclaration(declaration)) {
            *nextMembers = new (_pool) DeclarationListAST;
            (*nextMembers)->value = declaration;
            nextMembers = &(*nextMembers)->next;
        }

        match(T_AT_END, &ast->end_token);

        node = ast;
        return true;
    }
}

// objc-protocol ::= T_AT_PROTOCOL (T_IDENTIFIER @ T_COMMA) T_SEMICOLON
//
bool Parser::parseObjCProtocol(DeclarationAST *&node,
                               SpecifierListAST *attributes)
{
    DEBUG_THIS_RULE();
    if (! attributes && LA() == T___ATTRIBUTE__) {
        SpecifierListAST **attr = &attributes;
        while (parseGnuAttributeSpecifier(*attr))
            attr = &(*attr)->next;
    }

    if (LA() != T_AT_PROTOCOL)
        return false;

    int protocol_token = consumeToken();
    int identifier_token = 0;
    match(T_IDENTIFIER, &identifier_token);

    if (LA() == T_COMMA || LA() == T_SEMICOLON) {
        // a protocol forward declaration

        ObjCProtocolForwardDeclarationAST *ast = new (_pool) ObjCProtocolForwardDeclarationAST;
        ast->attribute_list = attributes;
        ast->protocol_token = protocol_token;
        ast->identifier_list = new (_pool) NameListAST;
        SimpleNameAST *name = new (_pool) SimpleNameAST;
        name->identifier_token = identifier_token;
        ast->identifier_list->value = name;
        NameListAST **nextId = &ast->identifier_list->next;

        while (LA() == T_COMMA) {
            consumeToken(); // consume T_COMMA
            match(T_IDENTIFIER, &identifier_token);

            *nextId = new (_pool) NameListAST;
            name = new (_pool) SimpleNameAST;
            name->identifier_token = identifier_token;
            (*nextId)->value = name;
            nextId = &(*nextId)->next;
        }

        match(T_SEMICOLON, &ast->semicolon_token);
        node = ast;
        return true;
    } else {
        // a protocol definition
        ObjCProtocolDeclarationAST *ast = new (_pool) ObjCProtocolDeclarationAST;
        ast->attribute_list = attributes;
        ast->protocol_token = protocol_token;
        SimpleNameAST *name = new (_pool) SimpleNameAST;
        name->identifier_token = identifier_token;
        ast->name = name;

        parseObjCProtocolRefs(ast->protocol_refs);

        DeclarationListAST **nextMembers = &ast->member_declaration_list;
        DeclarationAST *declaration = nullptr;
        while (parseObjCInterfaceMemberDeclaration(declaration)) {
            *nextMembers = new (_pool) DeclarationListAST;
            (*nextMembers)->value = declaration;
            nextMembers = &(*nextMembers)->next;
        }

        match(T_AT_END, &ast->end_token);

        node = ast;
        return true;
    }
}

// objc-implementation ::= T_AT_IMPLEMENTAION T_IDENTIFIER (T_COLON T_IDENTIFIER)?
//                         objc-class-instance-variables-opt
// objc-implementation ::= T_AT_IMPLEMENTAION T_IDENTIFIER T_LPAREN T_IDENTIFIER T_RPAREN
//
bool Parser::parseObjCImplementation(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_AT_IMPLEMENTATION)
        return false;

    int implementation_token = consumeToken();
    int identifier_token = 0;
    match(T_IDENTIFIER, &identifier_token);

    if (LA() == T_LPAREN) {
        // a category implementation
        ObjCClassDeclarationAST *ast = new (_pool) ObjCClassDeclarationAST;
        ast->implementation_token = implementation_token;
        SimpleNameAST *class_name = new (_pool) SimpleNameAST;
        class_name->identifier_token = identifier_token;
        ast->class_name = class_name;

        match(T_LPAREN, &ast->lparen_token);
        SimpleNameAST *category_name = new (_pool) SimpleNameAST;
        match(T_IDENTIFIER, &category_name->identifier_token);
        ast->category_name = category_name;
        match(T_RPAREN, &ast->rparen_token);

        parseObjCMethodDefinitionList(ast->member_declaration_list);
        match(T_AT_END, &ast->end_token);

        node = ast;
    } else {
        // a class implementation
        ObjCClassDeclarationAST *ast = new (_pool) ObjCClassDeclarationAST;
        ast->implementation_token = implementation_token;
        SimpleNameAST *class_name = new (_pool) SimpleNameAST;
        class_name->identifier_token = identifier_token;
        ast->class_name = class_name;

        if (LA() == T_COLON) {
            ast->colon_token = consumeToken();
            SimpleNameAST *superclass = new (_pool) SimpleNameAST;
            match(T_IDENTIFIER, &superclass->identifier_token);
            ast->superclass = superclass;
        }

        parseObjClassInstanceVariables(ast->inst_vars_decl);
        parseObjCMethodDefinitionList(ast->member_declaration_list);
        match(T_AT_END, &ast->end_token);

        node = ast;
    }

    return true;
}

bool Parser::parseObjCMethodDefinitionList(DeclarationListAST *&node)
{
    DEBUG_THIS_RULE();
    DeclarationListAST **next = &node;

    while (LA() && LA() != T_AT_END) {
        int start = cursor();
        DeclarationAST *declaration = nullptr;

        switch (LA()) {
        case T_PLUS:
        case T_MINUS:
            parseObjCMethodDefinition(declaration);

            if (start == cursor())
                consumeToken();
            break;

        case T_SEMICOLON:
            consumeToken();
            break;

        case T_AT_SYNTHESIZE: {
            ObjCSynthesizedPropertiesDeclarationAST *ast = new (_pool) ObjCSynthesizedPropertiesDeclarationAST;
            ast->synthesized_token = consumeToken();
            ObjCSynthesizedPropertyListAST *last = new (_pool) ObjCSynthesizedPropertyListAST;
            ast->property_identifier_list = last;
            last->value = new (_pool) ObjCSynthesizedPropertyAST;
            match(T_IDENTIFIER, &last->value->property_identifier_token);

            if (LA() == T_EQUAL) {
                last->value->equals_token = consumeToken();

                match(T_IDENTIFIER, &last->value->alias_identifier_token);
            }

            while (LA() == T_COMMA) {
                consumeToken(); // consume T_COMMA

                last->next = new (_pool) ObjCSynthesizedPropertyListAST;
                last = last->next;

                last->value = new (_pool) ObjCSynthesizedPropertyAST;
                match(T_IDENTIFIER, &last->value->property_identifier_token);

                if (LA() == T_EQUAL) {
                    last->value->equals_token = consumeToken();

                    match(T_IDENTIFIER, &last->value->alias_identifier_token);
                }
            }

            match(T_SEMICOLON, &ast->semicolon_token);

            declaration = ast;
            break;
        }

        case T_AT_DYNAMIC: {
            ObjCDynamicPropertiesDeclarationAST *ast = new (_pool) ObjCDynamicPropertiesDeclarationAST;
            ast->dynamic_token = consumeToken();
            ast->property_identifier_list = new (_pool) NameListAST;
            SimpleNameAST *name = new (_pool) SimpleNameAST;
            match(T_IDENTIFIER, &name->identifier_token);
            ast->property_identifier_list->value = name;

            NameListAST *last = ast->property_identifier_list;
            while (LA() == T_COMMA) {
                consumeToken(); // consume T_COMMA

                last->next = new (_pool) NameListAST;
                last = last->next;
                name = new (_pool) SimpleNameAST;
                match(T_IDENTIFIER, &name->identifier_token);
                last->value = name;
            }

            match(T_SEMICOLON, &ast->semicolon_token);

            declaration = ast;
            break;
        }

        default:
            if (LA() == T_EXTERN && LA(2) == T_STRING_LITERAL) {
                parseDeclaration(declaration);
            } else {
                if (! parseBlockDeclaration(declaration)) {
                    rewind(start);
                    error(cursor(), "skip token `%s'", tok().spell());
                    consumeToken();
                }
            }
            break;
        } // switch

        if (declaration) {
            *next = new (_pool) DeclarationListAST;
            (*next)->value = declaration;
            next = &(*next)->next;
        }
    }

    return true;
}

bool Parser::parseObjCMethodDefinition(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    ObjCMethodPrototypeAST *method_prototype = nullptr;
    if (! parseObjCMethodPrototype(method_prototype))
        return false;

    ObjCMethodDeclarationAST *ast = new (_pool) ObjCMethodDeclarationAST;
    ast->method_prototype = method_prototype;

    // Objective-C allows you to write:
    // - (void) foo; { body; }
    // so a method is a forward declaration when it doesn't have a _body_.
    // However, we still need to read the semicolon.
    if (LA() == T_SEMICOLON)
        ast->semicolon_token = consumeToken();

    parseFunctionBody(ast->function_body);

    node = ast;
    return true;
}

// objc-protocol-refs ::= T_LESS (T_IDENTIFIER @ T_COMMA) T_GREATER
//
bool Parser::parseObjCProtocolRefs(ObjCProtocolRefsAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_LESS)
        return false;

    ObjCProtocolRefsAST *ast = new (_pool) ObjCProtocolRefsAST;

    match(T_LESS, &ast->less_token);

    int identifier_token = 0;
    match(T_IDENTIFIER, &identifier_token);
    ast->identifier_list = new (_pool) NameListAST;
    SimpleNameAST *name = new (_pool) SimpleNameAST;
    name->identifier_token = identifier_token;
    ast->identifier_list->value = name;
    NameListAST **nextId = &ast->identifier_list->next;

    while (LA() == T_COMMA) {
        consumeToken(); // consume T_COMMA
        match(T_IDENTIFIER, &identifier_token);

        *nextId = new (_pool) NameListAST;
        name = new (_pool) SimpleNameAST;
        name->identifier_token = identifier_token;
        (*nextId)->value = name;
        nextId = &(*nextId)->next;
    }

    match(T_GREATER, &ast->greater_token);
    node = ast;
    return true;
}

// objc-class-instance-variables ::= T_LBRACE
//                                   objc-instance-variable-decl-list-opt
//                                   T_RBRACE
//
bool Parser::parseObjClassInstanceVariables(ObjCInstanceVariablesDeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_LBRACE)
        return false;

    ObjCInstanceVariablesDeclarationAST *ast = new (_pool) ObjCInstanceVariablesDeclarationAST;
    match(T_LBRACE, &ast->lbrace_token);

    for (DeclarationListAST **next = &ast->instance_variable_list; LA(); next = &(*next)->next) {
        if (LA() == T_RBRACE)
            break;

        const int start = cursor();

        *next = new (_pool) DeclarationListAST;
        parseObjCInstanceVariableDeclaration((*next)->value);

        if (start == cursor()) {
            // skip stray token.
            error(cursor(), "skip stray token `%s'", tok().spell());
            consumeToken();
        }
    }

    match(T_RBRACE, &ast->rbrace_token);

    node = ast;
    return true;
}

// objc-interface-declaration ::= T_AT_REQUIRED
// objc-interface-declaration ::= T_AT_OPTIONAL
// objc-interface-declaration ::= T_SEMICOLON
// objc-interface-declaration ::= objc-property-declaration
// objc-interface-declaration ::= objc-method-prototype
bool Parser::parseObjCInterfaceMemberDeclaration(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    switch (LA()) {
    case T_AT_END:
        return false;

    case T_AT_REQUIRED:
    case T_AT_OPTIONAL:
        consumeToken();
        return true;

    case T_SEMICOLON:
        consumeToken();
        return true;

    case T_AT_PROPERTY: {
        return parseObjCPropertyDeclaration(node);
    }

    case T_PLUS:
    case T_MINUS: {
        ObjCMethodDeclarationAST *ast = new (_pool) ObjCMethodDeclarationAST;
        if (parseObjCMethodPrototype(ast->method_prototype)) {
            match(T_SEMICOLON, &ast->semicolon_token);
            node = ast;
            return true;
        } else {
            return false;
        }
    }

    case T_ENUM:
    case T_CLASS:
    case T_STRUCT:
    case T_UNION: {
        return parseSimpleDeclaration(node);
    }

    default: {
        return parseSimpleDeclaration(node);
    } // default

    } // switch
}

// objc-instance-variable-declaration ::= objc-visibility-specifier
// objc-instance-variable-declaration ::= block-declaration
//
bool Parser::parseObjCInstanceVariableDeclaration(DeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    switch (LA()) {
        case T_AT_PRIVATE:
        case T_AT_PROTECTED:
        case T_AT_PUBLIC:
        case T_AT_PACKAGE: {
            ObjCVisibilityDeclarationAST *ast = new (_pool) ObjCVisibilityDeclarationAST;
            ast->visibility_token = consumeToken();
            node = ast;
            return true;
        }

        default:
            return parseSimpleDeclaration(node);
    }
}

// objc-property-declaration ::=
//    T_AT_PROPERTY T_LPAREN (property-attribute @ T_COMMA) T_RPAREN simple-declaration
//
bool Parser::parseObjCPropertyDeclaration(DeclarationAST *&node, SpecifierListAST *attributes)
{
    DEBUG_THIS_RULE();
    if (LA() != T_AT_PROPERTY)
        return false;

    ObjCPropertyDeclarationAST *ast = new (_pool) ObjCPropertyDeclarationAST;
    ast->attribute_list = attributes;
    ast->property_token = consumeToken();

    if (LA() == T_LPAREN) {
        match(T_LPAREN, &ast->lparen_token);

        ObjCPropertyAttributeAST *property_attribute = nullptr;
        if (parseObjCPropertyAttribute(property_attribute)) {
            ast->property_attribute_list = new (_pool) ObjCPropertyAttributeListAST;
            ast->property_attribute_list->value = property_attribute;
            ObjCPropertyAttributeListAST *last = ast->property_attribute_list;

            while (LA() == T_COMMA) {
                consumeToken(); // consume T_COMMA
                last->next = new (_pool) ObjCPropertyAttributeListAST;
                last = last->next;
                if (!parseObjCPropertyAttribute(last->value)) {
                    error(_tokenIndex, "expected token `%s' got `%s'",
                          Token::name(T_IDENTIFIER), tok().spell());
                    break;
                }
            }
        }

        match(T_RPAREN, &ast->rparen_token);
    }

    if (parseSimpleDeclaration(ast->simple_declaration))
        node = ast;
    else
        error(_tokenIndex, "expected a simple declaration");

    return true;
}

// objc-method-prototype ::= (T_PLUS | T_MINUS) objc-method-decl objc-method-attrs-opt
//
// objc-method-decl ::= objc-type-name? objc-selector
// objc-method-decl ::= objc-type-name? objc-keyword-decl-list objc-parmlist-opt
//
bool Parser::parseObjCMethodPrototype(ObjCMethodPrototypeAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_PLUS && LA() != T_MINUS)
        return false;

    ObjCMethodPrototypeAST *ast = new (_pool) ObjCMethodPrototypeAST;
    ast->method_type_token = consumeToken();

    parseObjCTypeName(ast->type_name);

    if ((lookAtObjCSelector() && LA(2) == T_COLON) || LA() == T_COLON) {
        ObjCSelectorArgumentAST *argument = nullptr;
        ObjCMessageArgumentDeclarationAST *declaration = nullptr;
        parseObjCKeywordDeclaration(argument, declaration);

        ObjCSelectorAST *sel = new (_pool) ObjCSelectorAST;
        ast->selector = sel;
        ObjCSelectorArgumentListAST *lastSel = new (_pool) ObjCSelectorArgumentListAST;
        sel->selector_argument_list = lastSel;
        sel->selector_argument_list->value = argument;

        ast->argument_list = new (_pool) ObjCMessageArgumentDeclarationListAST;
        ast->argument_list->value = declaration;
        ObjCMessageArgumentDeclarationListAST *lastArg = ast->argument_list;

        while (parseObjCKeywordDeclaration(argument, declaration)) {
            lastSel->next = new (_pool) ObjCSelectorArgumentListAST;
            lastSel = lastSel->next;
            lastSel->value = argument;

            lastArg->next = new (_pool) ObjCMessageArgumentDeclarationListAST;
            lastArg = lastArg->next;
            lastArg->value = declaration;
        }

        while (LA() == T_COMMA) {
            consumeToken();

            if (LA() == T_DOT_DOT_DOT) {
                ast->dot_dot_dot_token = consumeToken();
                break;
            }

            // TODO: Is this still valid, and if so, should it be stored in the AST? (EV)
            ParameterDeclarationAST *parameter_declaration = nullptr;
            parseParameterDeclaration(parameter_declaration);
        }
    } else if (lookAtObjCSelector()) {
        ObjCSelectorAST *sel = new (_pool) ObjCSelectorAST;
        sel->selector_argument_list = new (_pool) ObjCSelectorArgumentListAST;
        sel->selector_argument_list->value = new (_pool) ObjCSelectorArgumentAST;
        parseObjCSelector(sel->selector_argument_list->value->name_token);
        ast->selector = sel;
    } else {
        error(cursor(), "expected a selector");
    }

    SpecifierListAST **attr = &ast->attribute_list;
    while (parseGnuAttributeSpecifier(*attr))
        attr = &(*attr)->next;

    node = ast;
    return true;
}

// objc-property-attribute ::= getter '=' identifier
// objc-property-attribute ::= setter '=' identifier ':'
// objc-property-attribute ::= readonly
// objc-property-attribute ::= readwrite
// objc-property-attribute ::= assign
// objc-property-attribute ::= retain
// objc-property-attribute ::= copy
// objc-property-attribute ::= nonatomic
bool Parser::parseObjCPropertyAttribute(ObjCPropertyAttributeAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_IDENTIFIER)
        return false;

    node = new (_pool) ObjCPropertyAttributeAST;

    const Identifier *id = tok().identifier;
    const int k = classifyObjectiveCContextKeyword(id->chars(), id->size());
    switch (k) {
    case Token_copy:
    case Token_assign:
    case Token_retain:
    case Token_readonly:
    case Token_readwrite:
    case Token_nonatomic:
        node->attribute_identifier_token = consumeToken();
        return true;

    case Token_getter: {
        node->attribute_identifier_token = consumeToken();
        match(T_EQUAL, &node->equals_token);
        ObjCSelectorAST *sel = new (_pool) ObjCSelectorAST;
        sel->selector_argument_list = new (_pool) ObjCSelectorArgumentListAST;
        sel->selector_argument_list->value = new (_pool) ObjCSelectorArgumentAST;
        match(T_IDENTIFIER, &sel->selector_argument_list->value->name_token);
        node->method_selector = sel;
        return true;
    }

    case Token_setter: {
        node->attribute_identifier_token = consumeToken();
        match(T_EQUAL, &node->equals_token);
        ObjCSelectorAST *sel = new (_pool) ObjCSelectorAST;
        sel->selector_argument_list = new (_pool) ObjCSelectorArgumentListAST;
        sel->selector_argument_list->value = new (_pool) ObjCSelectorArgumentAST;
        match(T_IDENTIFIER, &sel->selector_argument_list->value->name_token);
        match(T_COLON, &sel->selector_argument_list->value->colon_token);
        node->method_selector = sel;
        return true;
    }

    default:
        return false;
    }
}

// objc-type-name ::= T_LPAREN objc-type-qualifiers-opt type-id T_RPAREN
//
bool Parser::parseObjCTypeName(ObjCTypeNameAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_LPAREN)
        return false;

    ObjCTypeNameAST *ast = new (_pool) ObjCTypeNameAST;
    match(T_LPAREN, &ast->lparen_token);
    parseObjCTypeQualifiers(ast->type_qualifier_token);
    parseTypeId(ast->type_id);
    match(T_RPAREN, &ast->rparen_token);
    node = ast;
    return true;
}

// objc-selector ::= T_IDENTIFIER | keyword
//
bool Parser::parseObjCSelector(int &selector_token)
{
    DEBUG_THIS_RULE();
    if (! lookAtObjCSelector())
        return false;

    selector_token = consumeToken();
    return true;
}

// objc-keyword-decl ::= objc-selector? T_COLON objc-type-name? objc-keyword-attributes-opt T_IDENTIFIER
//
bool Parser::parseObjCKeywordDeclaration(ObjCSelectorArgumentAST *&argument, ObjCMessageArgumentDeclarationAST *&node)
{
    DEBUG_THIS_RULE();
    if (! (LA() == T_COLON || (lookAtObjCSelector() && LA(2) == T_COLON)))
        return false;

    node = new (_pool) ObjCMessageArgumentDeclarationAST;
    argument = new (_pool) ObjCSelectorArgumentAST;

    parseObjCSelector(argument->name_token);
    match(T_COLON, &argument->colon_token);

    parseObjCTypeName(node->type_name);

    SpecifierListAST **attr = &node->attribute_list;
    while (parseGnuAttributeSpecifier(*attr))
        attr = &(*attr)->next;

    SimpleNameAST *param_name = new (_pool) SimpleNameAST;
    match(T_IDENTIFIER, &param_name->identifier_token);
    node->param_name = param_name;

    return true;
}

bool Parser::parseObjCTypeQualifiers(int &type_qualifier)
{
    DEBUG_THIS_RULE();
    if (LA() != T_IDENTIFIER)
        return false;

    const Identifier *id = tok().identifier;
    switch (classifyObjectiveCContextKeyword(id->chars(), id->size())) {
    case Token_bycopy:
    case Token_byref:
    case Token_in:
    case Token_inout:
    case Token_oneway:
    case Token_out:
        type_qualifier = consumeToken();
        return true;
    default:
        return false;
    }
}

bool Parser::peekAtObjCContextKeyword(int kind)
{
    if (LA() != T_IDENTIFIER)
        return false;

    const Identifier *id = tok().identifier;
    const int k = classifyObjectiveCContextKeyword(id->chars(), id->size());
    return k == kind;
}

bool Parser::parseObjCContextKeyword(int kind, int &in_token)
{
    DEBUG_THIS_RULE();

    if (!peekAtObjCContextKeyword(kind))
        return false;

    in_token = consumeToken();
    return true;
}

int Parser::peekAtQtContextKeyword() const
{
    DEBUG_THIS_RULE();
    if (LA() != T_IDENTIFIER)
        return false;

    const Identifier *id = tok().identifier;
    return classifyQtContextKeyword(id->chars(), id->size());
}

bool Parser::parseLambdaExpression(ExpressionAST *&node)
{
    DEBUG_THIS_RULE();

    LambdaIntroducerAST *lambda_introducer = nullptr;
    if (parseLambdaIntroducer(lambda_introducer)) {
        LambdaExpressionAST *ast = new (_pool) LambdaExpressionAST;
        ast->lambda_introducer = lambda_introducer;
        if (_languageFeatures.cxx20Enabled && LA() == T_LESS) {
            consumeToken();
            parseTemplateParameterList(ast->templateParameters);
            if (LA() != T_GREATER)
                return false;
            consumeToken();
            parseRequiresClauseOpt(ast->requiresClause);
        }
        parseOptionalAttributeSpecifierSequence(ast->attributes);
        parseLambdaDeclarator(ast->lambda_declarator);
        parseCompoundStatement(ast->statement);
        node = ast;
        return true;
    }

    return false;
}

bool Parser::parseLambdaIntroducer(LambdaIntroducerAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_LBRACKET)
        return false;

    LambdaIntroducerAST *ast = new (_pool) LambdaIntroducerAST;
    ast->lbracket_token = consumeToken();

    if (LA() != T_RBRACKET)
        parseLambdaCapture(ast->lambda_capture);

    if (LA() == T_RBRACKET) {
        ast->rbracket_token = consumeToken();

        // FIXME: Attributes are also allowed ...
        if (LA() == T_LPAREN || LA() == T_LBRACE
            || (_languageFeatures.cxx20Enabled && LA() == T_LESS)) {
            node = ast;
            return true;
        }
    }

    return false;
}

bool Parser::parseLambdaCapture(LambdaCaptureAST *&node)
{
    DEBUG_THIS_RULE();
    bool startsWithDefaultCapture = false;

    int default_capture = 0;
    CaptureListAST *capture_list = nullptr;

    if (LA() == T_AMPER || LA() == T_EQUAL) {
        if (LA(2) == T_COMMA || LA(2) == T_RBRACKET) {
            startsWithDefaultCapture = true;
            default_capture = consumeToken(); // consume capture-default
        }
    }

    if (startsWithDefaultCapture && LA() == T_COMMA) {
        consumeToken(); // consume ','
        parseCaptureList(capture_list); // required

    } else if (LA() != T_RBRACKET) {
        parseCaptureList(capture_list); // optional

    }

    LambdaCaptureAST *ast = new (_pool) LambdaCaptureAST;
    ast->default_capture_token = default_capture;
    ast->capture_list = capture_list;
    node = ast;

    return true;
}

bool Parser::parseCapture(CaptureAST *&node)
{
    DEBUG_THIS_RULE();

    if (LA() == T_THIS) {
        consumeToken();
        return true;
    }

    if (LA() == T_AMPER)
        consumeToken();

    if (LA() == T_IDENTIFIER) {
        SimpleNameAST *ast = new (_pool) SimpleNameAST;
        ast->identifier_token = consumeToken();

        node = new (_pool) CaptureAST;
        node->identifier = ast;
        return true;
    }

    return false;
}

bool Parser::parseCaptureList(CaptureListAST *&node)
{
    DEBUG_THIS_RULE();

    CaptureAST *capture = nullptr;

    if (parseCapture(capture)) {
        node = new (_pool) CaptureListAST;
        node->value = capture;

        CaptureListAST **l = &node->next;
        while (LA() == T_COMMA) {
            consumeToken(); // consume `,'
            CaptureAST *capture = nullptr;
            parseCapture(capture);
            if (capture) {
                *l = new (_pool) CaptureListAST;
                (*l)->value = capture;
                l = &(*l)->next;
            }
        }

        return true;
    }

    return false;
}

bool Parser::parseLambdaDeclarator(LambdaDeclaratorAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_LPAREN)
        return false;

    LambdaDeclaratorAST *ast = new (_pool) LambdaDeclaratorAST;

    ast->lparen_token = consumeToken(); // consume `('
    parseParameterDeclarationClause(ast->parameter_declaration_clause);
    match(T_RPAREN, &ast->rparen_token);

    SpecifierListAST **attr = &ast->attributes;
    while (parseGnuAttributeSpecifier(*attr))
        attr = &(*attr)->next;
    while (parseStdAttributeSpecifier(*attr))
        attr = &(*attr)->next;

    if (LA() == T_MUTABLE)
        ast->mutable_token = consumeToken();

    parseExceptionSpecification(ast->exception_specification);
    parseTrailingReturnType(ast->trailing_return_type);
    parseRequiresClauseOpt(ast->requiresClause);
    node = ast;

    return true;
}

bool Parser::parseTrailingReturnType(TrailingReturnTypeAST *&node)
{
    DEBUG_THIS_RULE();
    if (LA() != T_ARROW)
        return false;

    TrailingReturnTypeAST *ast = new (_pool) TrailingReturnTypeAST;

    ast->arrow_token = consumeToken();

    SpecifierListAST **attr = &ast->attributes;
    while (parseGnuAttributeSpecifier(*attr))
        attr = &(*attr)->next;
    while (parseStdAttributeSpecifier(*attr))
        attr = &(*attr)->next;

    parseTrailingTypeSpecifierSeq(ast->type_specifier_list);
    parseAbstractDeclarator(ast->declarator, ast->type_specifier_list);
    node = ast;
    return true;
}

void Parser::rewind(int cursor)
{
#ifndef CPLUSPLUS_NO_DEBUG_RULE
    if (cursor != _tokenIndex)
        fprintf(stderr, "! rewinding from token %d to token %d\n", _tokenIndex, cursor);
#endif

    const int n = _translationUnit->tokenCount();
    if (cursor < n)
        _tokenIndex = cursor;
    else
        _tokenIndex = n - 1;
}

void Parser::warning(int index, const char *format, ...)
{
    va_list args, ap;
    va_start(args, format);
    va_copy(ap, args);
    _translationUnit->message(DiagnosticClient::Warning, index, format, ap);
    va_end(ap);
    va_end(args);
}

void Parser::error(int index, const char *format, ...)
{
    va_list args, ap;
    va_start(args, format);
    va_copy(ap, args);
    _translationUnit->message(DiagnosticClient::Error, index, format, ap);
    va_end(ap);
    va_end(args);
}

void Parser::fatal(int index, const char *format, ...)
{
    va_list args, ap;
    va_start(args, format);
    va_copy(ap, args);
    _translationUnit->message(DiagnosticClient::Fatal, index, format, ap);
    va_end(ap);
    va_end(args);
}
