// logic (MVS).
//
// retract directives are not de-duplicated since comments are
// meaningful, and versions may be retracted multiple times.
func (f *File) removeDups() {
	removeDups(f.Syntax, &f.Exclude, &f.Replace)
}

func removeDups(syntax *FileSyntax, exclude *[]*Exclude, replace *[]*Replace) {
	kill := make(map[*Line]bool)

	// Remove duplicate excludes.
	if exclude != nil {