d3d9: Properly retrieve an interface pointer in IDirect3DDevice9Impl_GetVertexShader().

dlls/d3d9/device.c

@@ -2339,6 +2339,7 @@ static HRESULT WINAPI IDirect3DDevice9Impl_GetVertexShader(IDirect3DDevice9Ex *i
         IDirect3DVertexShader9 **shader)
 {
     IDirect3DDevice9Impl *This = impl_from_IDirect3DDevice9Ex(iface);
+    IDirect3DVertexShader9Impl *shader_impl;
     struct wined3d_shader *wined3d_shader;
 
     TRACE("iface %p, shader %p.\n", iface, shader);
@@ -2347,7 +2348,8 @@ static HRESULT WINAPI IDirect3DDevice9Impl_GetVertexShader(IDirect3DDevice9Ex *i
     wined3d_shader = wined3d_device_get_vertex_shader(This->wined3d_device);
     if (wined3d_shader)
     {
-        *shader = wined3d_shader_get_parent(wined3d_shader);
+        shader_impl = wined3d_shader_get_parent(wined3d_shader);
+        *shader = &shader_impl->IDirect3DVertexShader9_iface;
         IDirect3DVertexShader9_AddRef(*shader);
         wined3d_shader_decref(wined3d_shader);
     }