Why isnt this working....

res/shaders/LegacyBasePass.slang

@@ -15,12 +15,11 @@ layout(set=2)
 ParameterBlock<Scene> pScene;
 
 [shader("vertex")]
-void vertexMain(	
+FragmentParameter vertexMain(	
 	uint vertexId: SV_VertexID,
 	uint instanceId: SV_InstanceID,
-	out FragmentParameter params: PARAMETER,
-){
+) : PARAMETER{
 	InstanceData inst = pScene.instances[instanceId];
 	VertexAttributes attr = pVertexData.getAttributes(vertexId, inst.transformMatrix);
-	params = attr.getParameter(inst.transformMatrix);
+	return attr.getParameter(inst.transformMatrix);
 }

res/shaders/lib/MaterialParameter.slang

@@ -20,13 +20,14 @@ struct LightingParameter
 // data passed to fragment shader
 struct FragmentParameter
 {
+	// clip position has to be the first attribute for some reason????
+	float4 position_CS : SV_Position;
 	float3 position_TS;
 	float3 viewDir_TS;
 	float3 normal_WS;
 	float3 tangent_WS;
 	float3 biTangent_WS;
 	float3 position_WS;
-	float4 position_CS : SV_Position;
 	float2 texCoords;
 	float3 vertexColor;
 	MaterialParameter getMaterialParameter()