diff --git a/src/mesa/state_tracker/st_context.h b/src/mesa/state_tracker/st_context.h
index 35c89321a54..91b0f975f3f 100644
--- a/src/mesa/state_tracker/st_context.h
+++ b/src/mesa/state_tracker/st_context.h
@@ -65,8 +65,8 @@ struct u_upload_mgr;
 
 
 struct st_state_flags {
-   GLuint mesa;
-   uint64_t st;
+   GLbitfield mesa;  /**< Mask of _NEW_x flags */
+   uint64_t st;      /**< Mask of ST_NEW_x flags */
 };
 
 struct st_tracked_state {