LibraryImport - Marshalling struct from a referenced project.

[ykarpeev]

Hello, I am trying to use LibraryImport and have found an issue where if my structure is in a different project I will get SYSLIB1501. I am using net8.

This code works:

 public partial class Class1
   {
       [LibraryImport("")]
       private static partial long Test(Test1 x);
   }

   public struct Test1
   {
       uint F1;
   }

But if I move the Test1 struct into a separate project that is referenced by the one with the libraryimport I will get an error:

Severity Code Description Project File Line Suppression State
Error SYSLIB1051 Runtime marshalling must be disabled in this project by applying the 'System.Runtime.CompilerServices.DisableRuntimeMarshallingAttribute' to the assembly to enable marshalling this type. The generated source will not handle marshalling of parameter 'x'. (https://learn.microsoft.com/dotnet/fundamentals/syslib-diagnostics/syslib1051) LibraryImportIssue

Am I missing something? I would like to keep the layout the same and keep my objects in a services library to prevent some circular dependencies issues.

[ykarpeev]

I found an issue for this: #98616 & it looks like this is by design and the solution would be to use a custom marshaller.