diff --git a/tests/lua/ty2.lua b/tests/lua/ty2.lua
new file mode 100644
index 000000000..4fc5361be
--- /dev/null
+++ b/tests/lua/ty2.lua
@@ -0,0 +1,12 @@
+local env     = environment()
+local inferer = type_inferer(env)
+env:add_var("N", Type())
+local N = Const("N")
+env:add_var("a", N)
+local ctx = context()
+ctx = extend(ctx, "x", N)
+assert(inferer(Var(0), ctx) == N)
+assert(not pcall(function() inferer(Var(1), ctx) end))
+inferer:clear()
+assert(inferer(Var(0), ctx) == N)
+assert(is_type_inferer(inferer))