Protected Internal members are not visible in F# with InternalsVisibleTo

[0x53A]

protected internal in C# means famorassem, e.g. the visibility is the superset of protected and internal.

Repro steps

Class in C#:

namespace A
{
    public class Class1
    {
        protected static int Protected;
        internal static int Internal;
        protected internal static int ProtectedInternal;
        public static int Public;
    }
}

I added this to the AssemblyInfo.cs

[assembly: InternalsVisibleTo("B")]
[assembly: InternalsVisibleTo("C")]

I then added two additional projects, B (C#) and C (F#).

C#

F#

(The internal member is visible, so InternalsVisibleTo works in general)

Expected behavior

I would have expected the member ProtectedInternal to be visible.

Actual behavior

Only Internal (and public ofc.) is visible

Please not that this is notjust a tooling issue - when I try to compile the project, I get this error message:

A.Class1.ProtectedInternal <- 5

error FS1097: The struct or class field 'ProtectedInternal' is not accessible from this code location

Known workarounds

I need to modify the C# project and make the member either only internal, so that InternalsVisibleTo works, or make it public.

Related information

Provide any related information

[dsyme]

Fix linked above, thanks for the excellent bug report

[0x53A]

@dsyme damn, that was fast, thanks!

There is also one other visibility in IL, famANDassembly, e.g. it can only be accessed by sub-types in the same assembly (and by subtypes in other assemblies, if you use InternalsVisibleTo)

AFAIK it is not yet possible to generate this via any language, but C# had wanted to implement it for C#6 (not sure if it was postponed to C#7 or completeley scraped), and there is always the possibility to muck with IL manually...

I modified an assembly with DnSpy:

The member is invisible outside the subtype

The member is visible inside the subtype

In F#, the FamAndAssembly member is NOT visible, but funnily, the ProtectedInternal member is visible in the subtype.

This was tested with the same version ( so without your fix).

Attached is the modified assembly (A.dll)
A.zip

[ReedCopsey]

famANDassembly

Note that you can generate types/methods with this access in C++/CLI (it's
the public protected: modifier).

[dsyme]

I'll close this - please open a separate issue for the one above