rule/rule.go
func (l *Load) Remove(sym string) {
	if _, ok := l.symbols[sym]; ok {
		delete(l.symbols, sym)
		l.updated = true
	}
}
func (l *Load) Remove(sym string) {
	if _, ok := l.symbols[sym]; ok {
		delete(l.symbols, sym)
		l.updated = true
	}
}
// Remove deletes a symbol from the load statement. This has no effect if
// the symbol is not loaded.