Please do the checklist before filing an issue:

• I have read the documentation, including the FAQ
• I can reproduce the bug using the latest prerelease version
• I have searched existing discussion and issue to avoid duplicates

Describe the bug
Adding a clone/copy map definition with a class that has a read-only property throws InsufficientExecutionStackException (similar to #1882 ?)

Repro
https://github.com/nas-rda/Mapperly1882Extended

Declaration code

public class Sample
{
    public string Value { get; set; }

    public Task? ReadonlyProperty => null;
}

[Mapper(RequiredMappingStrategy = RequiredMappingStrategy.Target, UseDeepCloning = true)]
public static partial class Map
{
    public static partial void Copy(this Sample source, Sample target);
}

Actual relevant generated code
None. InsufficientExecutionStackException is thrown in MapperGenerator.

Expected relevant generated code

public static partial class Map
{
    public static partial void Copy(this Sample source, Sample target)
    {
        target.Value = source.Value;
    }
}

Reported relevant diagnostics
None.

Environment (please complete the following information):

• Mapperly Version: 4.3.1-next.0
• Nullable reference types: enabled
• .NET Version: 10.0.0
• Target Framework: net10.0
• Compiler Version: 18.0.2+b0f34d51f
• C# Language Version: 14.0
• IDE: Rider 2025.3.0.4
• OS: Windows 10 22H2

Workaround
Using MapperIgnoreTarget(nameof(@Sample.ReadonlyProperty)) will not cause the exception.