var _ … type fileInfo … // Name returns the name of the file func (fi fileInfo) Name() string { … } // Size returns the size of the file func (fi fileInfo) Size() int64 { … } // Mode returns the file mode func (fi fileInfo) Mode() os.FileMode { … } // ModTime returns a bogus time func (fi fileInfo) ModTime() time.Time { … } // IsDir returns true if it is a directory func (fi fileInfo) IsDir() bool { … } // Sys should return underlying data source, but it now returns nil func (fi fileInfo) Sys() interface{ … }