What's wrong with this code?

[Chris via Digitalmars-d-learn]

Update:

If I add *also* a auto vec2 = vec; now the code works. So it 
looks like this now:

		voxel_vec [string] move_buttons = [
			"button_xp" : voxel_vec ([ 1, 0, 0 ]),
			"button_xm" : voxel_vec ([ -1, 0, 0 ]),
			"button_yp" : voxel_vec ([ 0, 1, 0 ]),
			"button_ym" : voxel_vec ([ 0, -1, 0 ]),
			"button_zp" : voxel_vec ([ 0, 0, 1 ]),
			"button_zm" : voxel_vec ([ 0, 0, -1 ]) ];

		foreach (bname, vec; move_buttons) {
			Button bmove = cast (Button) g.getObject (bname);

			bmove.addOnClicked (delegate void (Button aux) {
				auto glw2 = glw;
				auto vec2 = vec;

				if (!glw2.sel_active) return;

				glw2.vf.move (3, vec2, glw2.sel_limits);
				glw2.set_mesh (glw2.vf.polygonize);
			} );
		}

and works as expected. I'm going to leave it like that in the 
belief it's a compiler bug, if someone wants to take a look at 
the full source I'm willing to disclose it.

Thanks again for the help and the idea of the work around.