Strange Issues regarding aliases

[Joerg Joergonson via Digitalmars-d-learn]

I have stuff like


public static class fGL
{
	nothrow @nogc extern(System)
	{
		alias CullFace = void function(tGL.Enum);
		alias FrontFace = void function(tGL.Enum);
		alias HInt = void function(tGL.Enum, tGL.Enum);
		alias LineWidth = void function(tGL.Float);
		alias PoIntSize = void function(tGL.Float);
                 ...
         }
}


public static struct tGL
{
	alias Void = void;
	alias IntPtr = ptrdiff_t;
	alias SizeInt = int;
	alias Char = char;
	alias CharARB = byte;
	alias uShort = ushort;
	alias Int64EXT = long;
	alias Short = short;
	alias uInt64 = ulong;
	alias HalfARB = ushort;
         alias BlendFunc = void function(tGL.Enum, tGL.Enum);
         ...

         __gshared {
	    CopyTexImage1D glCopyTexImage1D;
             TextureParameterf glTextureParameterf;
             VertexAttribI3ui glVertexAttribI3ui;
             VertexArrayElementBuffer glVertexArrayElementBuffer;
             BlendFunc glBlendFunc;
             ...
}


public struct eGL
{
	enum ubyte FALSE = 0;
	enum ubyte TRUE = 1;
	enum uint NO_ERROR = 0;
	enum uint NONE = 0;
	enum uint ZERO = 0;
	enum uint ONE = 1;
         ...
}


And when I use this stuff(which is clearly openGL being cleaned 
up a bit(I know I can use modules to essentially do this too but 
that is irrelevant):

I get errors like


Error: null has no effect in expression (null)	

Error: more than one argument for construction of extern 
(Windows) void function(uint, uint) nothrow @nogc	


This is when using it like

fGL.BlendFunc(eGL.SRC_ALPHA, eGL.ONE_MINUS_SRC_ALPHA);

What's going on? Please no responses about "You are going to run 
into a lot of problems since all the openGL code uses the flat 
accessing"... The whole point is to get away from that ancient 
way and backwards way.