> ## Documentation Index
> Fetch the complete documentation index at: https://ancplua.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# AL0059 - Avoid lock on typeof(T)

> Type objects are global singletons, risking cross-assembly deadlocks

Source: [Al0057ToAl0060ThreadingAnalyzer.cs](https://github.com/ANcpLua/ANcpLua.Analyzers/blob/main/src/ANcpLua.Analyzers/Analyzers/Al0057ToAl0060ThreadingAnalyzer.cs)

## Description

`typeof(T)` returns a globally shared `Type` object. Locking on it creates cross-assembly deadlock risks.

## Bad Code

```csharp theme={null}
public void Update()
{
    lock (typeof(MyService)) { _count++; }
}
```

## Good Code

```csharp theme={null}
private static readonly object s_lock = new();
public void Update()
{
    lock (s_lock) { _count++; }
}
```

## Properties

* **Category**: Threading
* **Severity**: Warning
* **Enabled by default**: True
* **Code fix available**: False

## Configuration

```editorconfig theme={null}
dotnet_diagnostic.AL0059.severity = warning
```