AL0053 - Unnecessary AotUnsafe attribute

The [AotUnsafe] attribute is applied to code that doesn’t use any AOT-incompatible patterns

Source: AL0053UnnecessaryAotUnsafeAnalyzer.cs

Description

This analyzer detects when [AotUnsafe] is applied to code that doesn’t actually use any AOT-incompatible patterns. This helps prevent over-annotation where developers mark code as unsafe “just to be safe” when it’s actually AOT-compatible.

The analyzer checks for these AOT-incompatible patterns:

• Calls to methods with [RequiresDynamicCode]
• Calls to other [AotUnsafe] methods
• Reflection APIs: Type.GetMethod, Type.GetProperty, PropertyInfo.GetValue, Activator.CreateInstance, etc.
• Reflection.Emit namespace usage
• dynamic keyword usage

Bad Code

// AL0053: This method doesn't use any AOT-incompatible patterns
[AotUnsafe("Not sure if this needs reflection")]
public string FormatName(string first, string last)
{
    return $"{first} {last}";
}

Good Code

// Option 1: Remove the attribute since the code is AOT-safe
public string FormatName(string first, string last)
{
    return $"{first} {last}";
}

// Option 2: If you actually use reflection, the attribute is justified
[AotUnsafe("Duck-typing response objects")]
public object? GetPropertyValue(object obj, string name)
{
    return obj.GetType().GetProperty(name)?.GetValue(obj);
}

Properties

• Category: AOT Testing
• Severity: Warning (Suggestion)
• Enabled by default: True
• Code fix available: False

Configuration

dotnet_diagnostic.AL0053.severity = suggestion

Detected Patterns

The analyzer recognizes these as legitimate reasons for [AotUnsafe]:

Pattern	Example
[RequiresDynamicCode] calls	JsonSerializer.Deserialize<T>() (without source gen)
[AotUnsafe] method calls	ReflectionHelper.Extract()
Type.GetProperty	type.GetProperty("Name")
Type.GetMethod	type.GetMethod("Execute")
PropertyInfo.GetValue	prop.GetValue(obj)
Activator.CreateInstance	Activator.CreateInstance(type)
Expression.Compile	lambda.Compile()
Reflection.Emit types	new DynamicMethod(...)
dynamic keyword	dynamic obj = GetData();

See Also

• AL0052 - AotSafe code must not call AotUnsafe code
• AL0044 - AotSafe code must not call RequiresDynamicCode methods
• AotUnsafe attribute documentation