# Typestate Pattern in Go: Separate Structs

In Go, we can implement the typestate pattern similarly to the Rust "Builder Pattern" solution by using separate structs for each state.

```go
pwLocked := NewCredentialManager()
pwUnlocked := pwLocked.Unlock("pssst")
pwUnlocked.Set("foo", "bar")
_, _ = pwUnlocked.Get("foo")
pwUnlocked.Lock()
```

By returning a different struct type from `Unlock` and `Lock`, we can control which methods are available on the returned object.

## Caveats

Unlike Rust, Go does not have an ownership model. This means that the original object (e.g., `pwLocked`) remains valid and usable even after it has been "moved" to a new state. This can lead to logic errors if the old object is reused.

```go
pwLocked := NewCredentialManager()
pwUnlocked := pwLocked.Unlock("pssst")
pwLocked.Unlock("pssst") // Still possible! 💥
```