code: func ExpandPackagesNoVendor(patterns []string) []string {
  	expand := false
  	for _, pkg := range patterns {
  		if strings.Contains(pkg, "...") {
  			expand = true
  		}
  	}
  	if expand {
  		cmd := GoTool("list", patterns...)
  		out, err := cmd.CombinedOutput()
  		if err != nil {
  			log.Fatalf("package listing failed: %v\n%s", err, string(out))
  		}
  		var packages []string
  		for _, line := range strings.Split(string(out), "\n") {
  			if !strings.Contains(line, "/vendor/") {
  				packages = append(packages, strings.TrimSpace(line))
  			}
  		}
  		return packages
  	}
  	return patterns
  }
docs: // ExpandPackagesNoVendor expands a cmd/go import path pattern, skipping
  // vendored packages.