privatelike provides an attribute, generator and analyzer to declare "private-like" types in C# (internal but producing errors if not used as if they were declared as private). This can be used to still enforce the same acessibility as using the private keyword in scenarios where types actually still need to be accessible from elsewhere in the assembly. For instance, this is the case for some source generators (eg. the COM generators, or the ones from ComputeSharp). Using the [privatelike] attribute can make things simpler in this scenario: the source generators can just suppress the errors, but the rest of the code will not, and should avoid referencing these types incorrectly.

Simply declare a type as follows:

[privatelike] partial struct MyPrivateLikeType
{  
}

The type will end up using internal, but referencing it from a place where it would've been an error if it had been using private will result in an error as well.