[ExpressiveProperty] stubs can't reference each other

[wassim-k]

Referencing a synthaised property in another ExpressiveProperty does not work.

Not sure if this is a limitation or something that can be supported

using ExpressiveSharp.Mapping;

public partial class Person
{
    [ExpressiveProperty("FirstName")]
    private string FirstNameExpr => "Jane";

    [ExpressiveProperty("FullName")]
    private string FullNameExpr => FirstName + " Doe";
}

Program.cs(8,36): warning EXP0008: Expression contains an unsupported operation (Invalid).
generated/.../_Person.FullName.g.cs(19,84): error CS1031: Type expected

Version: ExpressiveSharp 0.6.0