apply upstream fix

Author: lukaszsamson

lib/elixir_sense/core/compiler/quote.ex

@@ -559,8 +559,18 @@ defmodule ElixirSense.Core.Compiler.Quote do
   defp do_escape([], _, state), do: {[], state}
 
   defp do_escape([h | t], %__MODULE__{unquote: false} = q, state) do
-    {ht, state} = do_escape(h, q, state)
-    do_quote_simple_list(t, ht, q, state)
+    {eh, state} = do_escape(h, q, state)
+
+    case is_list(t) do
+      true ->
+        {et, state} = do_escape(t, q, state)
+        {[eh | et], state}
+
+      # improper list
+      false ->
+        {et, state} = do_escape(t, q, state)
+        {[{:|, [], [eh, et]}], state}
+    end
   end
 
   defp do_escape([h | t], q, state) do