private static async Task <Document> RefactorAsync(
Document document,
ExpressionSyntax expression,
SyntaxList <StatementSyntax> statements,
StatementContainer container,
int statementIndex,
int lastStatementIndex,
CancellationToken cancellationToken)
{
IEnumerable <StatementSyntax> blockStatements = statements
.Skip(statementIndex + 1)
.Take(lastStatementIndex - statementIndex);
IfStatementSyntax ifStatement = CreateNullCheck(expression, List(blockStatements));
if (lastStatementIndex < statements.Count - 1)
{
ifStatement = ifStatement.AppendTrailingTrivia(NewLineTrivia());
}
IEnumerable <StatementSyntax> newStatements = statements.Take(statementIndex + 1)
.Concat(new IfStatementSyntax[] { ifStatement })
.Concat(statements.Skip(lastStatementIndex + 1));
return(await document.ReplaceNodeAsync(container.Node, container.NodeWithStatements(newStatements), cancellationToken).ConfigureAwait(false));
}