Dynamic array of pointers to opaque structs

[Timon Gehr]

On 06/05/2013 10:34 PM, Johan F. wrote:
> I'm fiddling around with SDL2 using Derelict3, and I'm trying to make an
> array of SDL_Texture pointers, like so:
>
>      SDL_Texture*[] frames;
>      ... make texture ...
>      frames ~= texture;
>
> However, this yields the following error:
>
> /Users/jaffe1/prog/Derelict3/import/derelict/sdl2/types.d(1865): Error:
> struct derelict.sdl2.types.SDL_Texture is forward referenced when
> looking for 'toHash'
> /Users/jaffe1/prog/Derelict3/import/derelict/sdl2/types.d(1865): Error:
> struct derelict.sdl2.types.SDL_Texture is forward referenced when
> looking for 'opCmp'
> /Users/jaffe1/prog/Derelict3/import/derelict/sdl2/types.d(1865): Error:
> struct derelict.sdl2.types.SDL_Texture is forward referenced when
> looking for 'toString'
> /Users/jaffe1/prog/Derelict3/import/derelict/sdl2/types.d(1865): Error:
> struct derelict.sdl2.types.SDL_Texture unknown size
> /Users/jaffe1/prog/Derelict3/import/derelict/sdl2/types.d(1865): Error:
> struct derelict.sdl2.types.SDL_Texture no size yet for forward reference
> /Users/jaffe1/prog/Derelict3/import/derelict/sdl2/types.d(1865): Error:
> struct derelict.sdl2.types.SDL_Texture unknown size
> /Users/jaffe1/prog/Derelict3/import/derelict/sdl2/types.d(1865): Error:
> struct derelict.sdl2.types.SDL_Texture no size yet for forward reference
>
> At line 1865 in types.d is the opaque struct declaration
>
>      struct SDL_Texture;
>
> The program compiles and works fine if I change this line to
>
>      struct SDL_Texture {};
>
> This seems weird to me. Why is making an array of _pointers_ to
> SDL_Texture dependant on how the SDL_Texture struct is declared? Also,
> is simply adding {} the right way of fixing it, or will that possibly
> break something else?

It is a compiler bug, but we cannot confirm it unless you provide a 
minimal example that triggers it.