diff --git a/test/aeso_compiler_tests.erl b/test/aeso_compiler_tests.erl
index 35d7485..8e54991 100644
--- a/test/aeso_compiler_tests.erl
+++ b/test/aeso_compiler_tests.erl
@@ -876,9 +876,12 @@ failing_contracts() ->
                      "  `g5 : ((Animal) => Animal) => Cat`\n"
                      "to arguments\n"
                      "  `x : (Cat) => Cat`">>,
-                   <<?Pos(52, 44)
+                   <<?Pos(52,44)
                      "Cannot unify `Animal` and `Cat` in a covariant context\n"
-                     "when checking the type of the expression `f6() : option(Animal)` against the expected type `option(Cat)`">>
+                     "when checking the type of the expression `f6() : option(Animal)` against the expected type `option(Cat)`">>,
+                   <<?Pos(73,43)
+                     "Cannot unify `Animal` and `Cat` in a covariant context\n"
+                     "when checking the type of the expression `some_animal : Animal` against the expected type `Cat`">>
                   ])
     , ?TYPE_ERROR(polymorphism_variance_switching_custom_types,
                   [<<?Pos(56,39)
diff --git a/test/contracts/polymorphism_variance_switching.aes b/test/contracts/polymorphism_variance_switching.aes
index 48106c5..7b4dc38 100644
--- a/test/contracts/polymorphism_variance_switching.aes
+++ b/test/contracts/polymorphism_variance_switching.aes
@@ -61,3 +61,15 @@ main contract Main =
 
     stateful function g72() : cat_cat_map = { [Chain.create()] = Chain.create() }
     stateful function f72() : animal_animal_map = g13()
+
+    stateful function g73() =
+        let some_cat : Cat = Chain.create()
+        let some_animal : Animal = some_cat
+
+        let some_cat_cat_map : map(Cat, Cat) = g13()
+        let some_animal_animal_map : map(Animal, Animal) = some_cat_cat_map
+
+        let x : Animal = some_animal_animal_map[some_cat]  // success
+        let y : Cat    = some_cat_cat_map[some_animal]     // fail
+
+        ()