diff --git a/include/vkd3d_d3d12.idl b/include/vkd3d_d3d12.idl
index 9b1b494c..cdd3acec 100644
--- a/include/vkd3d_d3d12.idl
+++ b/include/vkd3d_d3d12.idl
@@ -2129,11 +2129,11 @@ typedef struct D3D12_PIPELINE_STATE_STREAM_DESC
     void *pPipelineStateSubobjectStream;
 } D3D12_PIPELINE_STATE_STREAM_DESC;
 
-struct D3D12_RT_FORMAT_ARRAY
+typedef struct D3D12_RT_FORMAT_ARRAY
 {
     DXGI_FORMAT RTFormats[D3D12_SIMULTANEOUS_RENDER_TARGET_COUNT];
     UINT NumRenderTargets;
-};
+} D3D12_RT_FORMAT_ARRAY;
 
 typedef enum D3D12_PIPELINE_STATE_SUBOBJECT_TYPE
 {