> ## 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.

# AL0095 - Avoid Expression.Compile() in AOT

> Expression.Compile() falls back to slow interpreted mode in AOT

Source: [Al0095AvoidExpressionCompileAnalyzer.cs](https://github.com/ANcpLua/ANcpLua.Analyzers/blob/main/src/ANcpLua.Analyzers/Analyzers/Al0095AvoidExpressionCompileAnalyzer.cs)

## Description

`Expression.Compile()` uses `Reflection.Emit` which is unavailable in AOT, falling back to a significantly slower interpreted mode.

## Bad Code

```csharp theme={null}
Expression<Func<int, int>> expr = x => x * 2;
var func = expr.Compile();
```

## Good Code

```csharp theme={null}
Func<int, int> func = x => x * 2;
// Or use source-generated alternatives
```

## Properties

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

## Configuration

```editorconfig theme={null}
dotnet_diagnostic.AL0095.severity = warning
```