Take a read of this: http://stackoverflow.com/a/32621854/1457000
The short of it is don't mixin stringof. Instead, mixin the actual template itself.
The functionLinkage might need to be string, but the types should remain literal. So try this:
mixin("alias Func = extern("~functionLinkage!Q~") (ReturnType!Q) function (Erase!(Parameters!Q));");
or something like that - don't concatenate strings of those, just make the string itself still say ReturnType!Q etc when you mix in. Then the scope will be correct.
