promql/engine.go
func (ev *evaluator) errorf(format string, args ...interface{}) {
	ev.error(errors.Errorf(format, args...))
}
func (ev *evaluator) errorf(format string, args ...interface{}) {
	ev.error(errors.Errorf(format, args...))
}
func ( ev * evaluator ) errorf ( format string , args ... interface { } ) { ev . error ( errors . Errorf ( format , args ... ) ) }
// errorf causes a panic with the input formatted into an error.
errorf causes a panic with the input formatted into an error .