diff --git a/lib/lsp_codegen/structure.ex b/lib/lsp_codegen/structure.ex
index ca21311..7ba0bcb 100644
--- a/lib/lsp_codegen/structure.ex
+++ b/lib/lsp_codegen/structure.ex
@@ -56,13 +56,26 @@ defmodule LSPCodegen.Structure do
         end)
 
       extends =
-        Enum.flat_map(structure.extends, fn e ->
-          Enum.find(structures, &(&1.raw_name == e.name)).properties
-        end)
+        Enum.flat_map(structure.extends, &all_properties_for(&1.name, structures))
 
       (structure.properties ++ mixins ++ extends) |> Enum.uniq_by(& &1.name)
     end
 
+    # recursively collects ALL properties for a structure by name
+    defp all_properties_for(name, structures) do
+      structure = Enum.find(structures, &(&1.raw_name == name))
+
+      mixins =
+        Enum.flat_map(structure.mixins, fn m ->
+          Enum.find(structures, &(&1.raw_name == m.name)).properties
+        end)
+
+      extends =
+        Enum.flat_map(structure.extends, &all_properties_for(&1.name, structures))
+
+      structure.properties ++ mixins ++ extends
+    end
+
     defp enforce(value) when value in [false, nil], do: ", enforce: true"
     defp enforce(true), do: ""