//---------------------------------------------------------------------------------------
        // ReportError
        //
        //  Generate a parser error.
        //  The function is told whether or not next call to GetToken() should return the same
        //  token or not
        //---------------------------------------------------------------------------------------
        private void ReportError(JsError errorId, JsContext context, bool skipToken)
        {
            Debug.Assert(context != null);
            int previousSeverity = m_severity;
            m_severity = JsException.GetSeverity(errorId);
            // EOF error is special and it's the last error we can possibly get
            if (JsToken.EndOfFile == context.Token)
                EOFError(errorId); // EOF context is special
            else
            {
                // report the error if not in error condition and the
                // error for this token is not worse than the one for the
                // previous token
                if (m_goodTokensProcessed > 0 || m_severity < previousSeverity)
                    context.HandleError(errorId);

                // reset proper info
                if (skipToken)
                    m_goodTokensProcessed = -1;
                else
                {
                    m_useCurrentForNext = true;
                    m_goodTokensProcessed = 0;
                }
            }
        }
        private JsFunctionObject ParseFunction(JsFunctionType functionType, JsContext fncCtx)
        {
            JsLookup name = null;
            JsAstNodeList formalParameters = null;
            JsBlock body = null;
            bool inExpression = (functionType == JsFunctionType.Expression);
            JsContext paramsContext = null;

            GetNextToken();

            // get the function name or make an anonymous function if in expression "position"
            if (JsToken.Identifier == m_currentToken.Token)
            {
                name = new JsLookup(m_currentToken.Clone(), this)
                    {
                        Name = m_scanner.Identifier
                    };
                GetNextToken();
            }
            else
            {
                string identifier = JsKeyword.CanBeIdentifier(m_currentToken.Token);
                if (null != identifier)
                {
                    name = new JsLookup(m_currentToken.Clone(), this)
                        {
                            Name = identifier
                        };
                    GetNextToken();
                }
                else
                {
                    if (!inExpression)
                    {
                        // if this isn't a function expression, then we need to throw an error because
                        // function DECLARATIONS always need a valid identifier name
                        ReportError(JsError.NoIdentifier, m_currentToken.Clone(), true);

                        // BUT if the current token is a left paren, we don't want to use it as the name.
                        // (fix for issue #14152)
                        if (m_currentToken.Token != JsToken.LeftParenthesis
                            && m_currentToken.Token != JsToken.LeftCurly)
                        {
                            identifier = m_currentToken.Code;
                            name = new JsLookup(CurrentPositionContext(), this)
                                {
                                    Name = identifier
                                };
                            GetNextToken();
                        }
                    }
                }
            }

            // make a new state and save the old one
            List<BlockType> blockType = m_blockType;
            m_blockType = new List<BlockType>(16);
            Dictionary<string, LabelInfo> labelTable = m_labelTable;
            m_labelTable = new Dictionary<string, LabelInfo>();

            try
            {
                // get the formal parameters
                if (JsToken.LeftParenthesis != m_currentToken.Token)
                {
                    // we expect a left paren at this point for standard cross-browser support.
                    // BUT -- some versions of IE allow an object property expression to be a function name, like window.onclick.
                    // we still want to throw the error, because it syntax errors on most browsers, but we still want to
                    // be able to parse it and return the intended results.
                    // Skip to the open paren and use whatever is in-between as the function name. Doesn't matter that it's
                    // an invalid identifier; it won't be accessible as a valid field anyway.
                    bool expandedIndentifier = false;
                    while (m_currentToken.Token != JsToken.LeftParenthesis
                        && m_currentToken.Token != JsToken.LeftCurly
                        && m_currentToken.Token != JsToken.Semicolon
                        && m_currentToken.Token != JsToken.EndOfFile)
                    {
                        name.Context.UpdateWith(m_currentToken);
                        GetNextToken();
                        expandedIndentifier = true;
                    }

                    // if we actually expanded the identifier context, then we want to report that
                    // the function name needs to be an identifier. Otherwise we didn't expand the
                    // name, so just report that we expected an open paren at this point.
                    if (expandedIndentifier)
                    {
                        name.Name = name.Context.Code;
                        name.Context.HandleError(JsError.FunctionNameMustBeIdentifier, false);
                    }
                    else
                    {
                        ReportError(JsError.NoLeftParenthesis, true);
                    }
                }

                if (m_currentToken.Token == JsToken.LeftParenthesis)
                {
                    // create the parameter list
                    formalParameters = new JsAstNodeList(m_currentToken.Clone(), this);
                    paramsContext = m_currentToken.Clone();

                    // skip the open paren
                    GetNextToken();

                    // create the list of arguments and update the context
                    while (JsToken.RightParenthesis != m_currentToken.Token)
                    {
                        String id = null;
                        m_noSkipTokenSet.Add(NoSkipTokenSet.s_FunctionDeclNoSkipTokenSet);
                        try
                        {
                            JsParameterDeclaration paramDecl = null;
                            if (JsToken.Identifier != m_currentToken.Token && (id = JsKeyword.CanBeIdentifier(m_currentToken.Token)) == null)
                            {
                                if (JsToken.LeftCurly == m_currentToken.Token)
                                {
                                    ReportError(JsError.NoRightParenthesis);
                                    break;
                                }
                                else if (JsToken.Comma == m_currentToken.Token)
                                {
                                    // We're missing an argument (or previous argument was malformed and
                                    // we skipped to the comma.)  Keep trying to parse the argument list --
                                    // we will skip the comma below.
                                    ReportError(JsError.SyntaxError, true);
                                }
                                else
                                {
                                    ReportError(JsError.SyntaxError, true);
                                    SkipTokensAndThrow();
                                }
                            }
                            else
                            {
                                if (null == id)
                                {
                                    id = m_scanner.Identifier;
                                }

                                paramDecl = new JsParameterDeclaration(m_currentToken.Clone(), this)
                                    {
                                        Name = id,
                                        Position = formalParameters.Count
                                    };
                                formalParameters.Append(paramDecl);
                                GetNextToken();
                            }

                            // got an arg, it should be either a ',' or ')'
                            if (JsToken.RightParenthesis == m_currentToken.Token)
                            {
                                break;
                            }
                            else if (JsToken.Comma == m_currentToken.Token)
                            {
                                // append the comma context as the terminator for the parameter
                                paramDecl.IfNotNull(p => p.TerminatingContext = m_currentToken.Clone());
                            }
                            else
                            {
                                // deal with error in some "intelligent" way
                                if (JsToken.LeftCurly == m_currentToken.Token)
                                {
                                    ReportError(JsError.NoRightParenthesis);
                                    break;
                                }
                                else
                                {
                                    if (JsToken.Identifier == m_currentToken.Token)
                                    {
                                        // it's possible that the guy was writing the type in C/C++ style (i.e. int x)
                                        ReportError(JsError.NoCommaOrTypeDefinitionError);
                                    }
                                    else
                                        ReportError(JsError.NoComma);
                                }
                            }

                            GetNextToken();
                        }
                        catch (RecoveryTokenException exc)
                        {
                            if (IndexOfToken(NoSkipTokenSet.s_FunctionDeclNoSkipTokenSet, exc) == -1)
                                throw;
                        }
                        finally
                        {
                            m_noSkipTokenSet.Remove(NoSkipTokenSet.s_FunctionDeclNoSkipTokenSet);
                        }
                    }

                    fncCtx.UpdateWith(m_currentToken);
                    GetNextToken();
                }

                // read the function body of non-abstract functions.
                if (JsToken.LeftCurly != m_currentToken.Token)
                    ReportError(JsError.NoLeftCurly, true);

                m_blockType.Add(BlockType.Block);
                m_noSkipTokenSet.Add(NoSkipTokenSet.s_BlockNoSkipTokenSet);
                m_noSkipTokenSet.Add(NoSkipTokenSet.s_StartStatementNoSkipTokenSet);
                try
                {
                    // parse the block locally to get the exact end of function
                    body = new JsBlock(m_currentToken.Clone(), this);
                    body.BraceOnNewLine = m_foundEndOfLine;
                    GetNextToken();

                    var possibleDirectivePrologue = true;
                    while (JsToken.RightCurly != m_currentToken.Token)
                    {
                        try
                        {
                            // function body's are SourceElements (Statements + FunctionDeclarations)
                            var statement = ParseStatement(true);
                            if (possibleDirectivePrologue)
                            {
                                var constantWrapper = statement as JsConstantWrapper;
                                if (constantWrapper != null && constantWrapper.PrimitiveType == JsPrimitiveType.String)
                                {
                                    // if it's already a directive prologues, we're good to go
                                    if (!(constantWrapper is JsDirectivePrologue))
                                    {
                                        // make the statement a directive prologue instead of a constant wrapper
                                        statement = new JsDirectivePrologue(constantWrapper.Value.ToString(), constantWrapper.Context, constantWrapper.Parser)
                                            {
                                                MayHaveIssues = constantWrapper.MayHaveIssues
                                            };
                                    }
                                }
                                else if (!m_newModule)
                                {
                                    // no longer considering constant wrappers
                                    possibleDirectivePrologue = false;
                                }
                            }
                            else if (m_newModule)
                            {
                                // we scanned into a new module -- we might find directive prologues again
                                possibleDirectivePrologue = true;
                            }

                            // add it to the body
                            body.Append(statement);
                        }
                        catch (RecoveryTokenException exc)
                        {
                            if (exc._partiallyComputedNode != null)
                            {
                                body.Append(exc._partiallyComputedNode);
                            }
                            if (IndexOfToken(NoSkipTokenSet.s_StartStatementNoSkipTokenSet, exc) == -1)
                                throw;
                        }
                    }

                    // make sure any important comments before the closing brace are kept
                    AppendImportantComments(body);

                    body.Context.UpdateWith(m_currentToken);
                    fncCtx.UpdateWith(m_currentToken);
                }
                catch (EndOfStreamException)
                {
                    // if we get an EOF here, we never had a chance to find the closing curly-brace
                    fncCtx.HandleError(JsError.UnclosedFunction, true);
                }
                catch (RecoveryTokenException exc)
                {
                    if (IndexOfToken(NoSkipTokenSet.s_BlockNoSkipTokenSet, exc) == -1)
                    {
                        exc._partiallyComputedNode = new JsFunctionObject(fncCtx, this)
                            {
                                FunctionType = (inExpression ? JsFunctionType.Expression : JsFunctionType.Declaration),
                                IdContext = name.IfNotNull(n => n.Context),
                                Name = name.IfNotNull(n => n.Name),
                                ParameterDeclarations = formalParameters,
                                ParametersContext = paramsContext,
                                Body = body
                            };
                        throw;
                    }
                }
                finally
                {
                    m_blockType.RemoveAt(m_blockType.Count - 1);
                    m_noSkipTokenSet.Remove(NoSkipTokenSet.s_StartStatementNoSkipTokenSet);
                    m_noSkipTokenSet.Remove(NoSkipTokenSet.s_BlockNoSkipTokenSet);
                }

                GetNextToken();
            }
            finally
            {
                // restore state
                m_blockType = blockType;
                m_labelTable = labelTable;
            }

            return new JsFunctionObject(fncCtx, this)
                {
                    FunctionType = functionType,
                    IdContext = name.IfNotNull(n => n.Context),
                    Name = name.IfNotNull(n => n.Name),
                    ParameterDeclarations = formalParameters,
                    ParametersContext = paramsContext,
                    Body = body
                };
        }