go so far as to …

Từ điển Oxford Advanced Learner 8th

go so/as far as to… idiom
to be willing to go to extreme or surprising limits in dealing with sth
•I wouldn't go as far as to say that he's a liar (= but I think he may be slightly dishonest).
•In June 2009 he went so far as to offer his resignation.
Main entry: ↑far_idiom