public abstract ImmutableArray<string> FixableDiagnosticIds { get; } //这里是对应的诊断代码ID

public virtual FixAllProvider GetFixAllProvider() //获取修复的方式 这里没搞明白

public abstract Task RegisterCodeFixesAsync(CodeFixContext context)//注册到方法中

        /// <summary>

        /// 修复代码

        /// 1 获取语义模型

        /// 2 找到正值表达式

        /// 3 给出正确的表达式

        /// 4 返回语法树新节点document

        /// </summary>

        /// <param name="document"></param>

        /// <param name="invocationExpr"></param>

        /// <param name="cancellationToken"></param>

        /// <returns></returns>

        private async Task<Document> FixRegexAsync(Document document,InvocationExpressionSyntax invocationExpr,CancellationToken cancellationToken)

        {

            var sementicModel = await document.GetSemanticModelAsync(cancellationToken);

            var memberAccessExpr = invocationExpr.Expression as MemberAccessExpressionSyntax;

            var memberSymbol = sementicModel.GetSymbolInfo(memberAccessExpr).Symbol as IMethodSymbol;

            var argumentList = invocationExpr.ArgumentList as ArgumentListSyntax;

            var regexLiteral =

                argumentList.Arguments[].Expression as LiteralExpressionSyntax;

            var regexOpt = sementicModel.GetConstantValue(regexLiteral);

            var regx = regexOpt.Value as string;

            var newLiteral = SyntaxFactory.ParseExpression("\"valid regex\"")

                .WithLeadingTrivia(regexLiteral.GetLeadingTrivia())

                .WithTrailingTrivia(regexLiteral.GetTrailingTrivia())

                .WithAdditionalAnnotations(Formatter.Annotation);

            var root = await document.GetSyntaxRootAsync();

            var newroot = root.ReplaceNode(regexLiteral, newLiteral);

            var newDocument = document.WithSyntaxRoot(newroot);

            return newDocument;

        }