Go: error "type assertion" vs "errors.Is()" vs "=="

effective go 里面的例子：

for try := 0; try < 2; try++ {
    file, err = os.Create(filename)
    if err == nil {
        return
    }
    if e, ok := err.(*os.PathError); ok && e.Err == syscall.ENOSPC {
        deleteTempFiles()  // Recover some space.
        continue
    }
    return
}

if e, ok := err.(*os.PathError);

"type assertion" vs "errors.Is()"

is it wrong to use type assertion for error handling?Stack Overflow

e.Err == syscall.ENOSPC

e.Err实现了error接口，syscall.ENOSPC是一个常量，让一个error去比较一个常量，怎么会这样？

"errors.Is()" vs "=="(equality operator)

How to compare Go errorsStack Overflow