// Read the raw bytes instead.
	content, tf, err := analysisutil.ReadFile(pass, filename)
	if err != nil {
		return err
	}

	check := newChecker(pass, filename, nil)
	check.nonGoFile(token.Pos(tf.Base()), string(content))
	return nil
}

type checker struct {
	pass     *analysis.Pass
	filename string
	file     *ast.File // nil for non-Go file