I was able to get this to compile, though I don't know why what I did worked. For the sake of completeness and closure I wanted to put it here.
I was declaring the Line enum and another enum inside the namespace scope along with another class. I removed the enums and put them in their own header files within the same namespace as before and it now compiles.
I am not sure what I was missing that this fixed the issue. If someone has any considerations please comment as to what this might have fixed.
Thanks for those that tried to help and sorry I wasn't able to put together an example the displayed the error.