code: func NewReadFile(id string, conf gosec.Config) (gosec.Rule, []ast.Node) {
  	rule := &readfile{
  		pathJoin: gosec.NewCallList(),
  		CallList: gosec.NewCallList(),
  		MetaData: gosec.MetaData{
  			ID:         id,
  			What:       "Potential file inclusion via variable",
  			Severity:   gosec.Medium,
  			Confidence: gosec.High,
  		},
  	}
  	rule.pathJoin.Add("path/filepath", "Join")
  	rule.pathJoin.Add("path", "Join")
  	rule.Add("io/ioutil", "ReadFile")
  	rule.Add("os", "Open")
  	return rule, []ast.Node{(*ast.CallExpr)(nil)}
  }
docs: // NewReadFile detects cases where we read files