diff --git a/src/aeso_ast_infer_types.erl b/src/aeso_ast_infer_types.erl
index a586460..7b2a399 100644
--- a/src/aeso_ast_infer_types.erl
+++ b/src/aeso_ast_infer_types.erl
@@ -3768,7 +3768,7 @@ mk_error({unpreserved_payablity, Kind, ContractCon, InterfaceCon}) ->
                   contract -> "contract";
                   contract_interface -> "interface"
               end,
-    Msg = io_lib:format("Non-payable ~s ~s cannot implement payable interface ~s",
+    Msg = io_lib:format("Non-payable ~s `~s` cannot implement payable interface `~s`",
                         [KindStr, name(ContractCon), name(InterfaceCon)]),
     mk_t_err(pos(ContractCon), Msg);
 mk_error(Err) ->
diff --git a/test/aeso_compiler_tests.erl b/test/aeso_compiler_tests.erl
index 67ada47..81f2cef 100644
--- a/test/aeso_compiler_tests.erl
+++ b/test/aeso_compiler_tests.erl
@@ -1155,6 +1155,26 @@ failing_contracts() ->
                      "to arguments\n"
                      "  `Chain.create : (value : int, var_args) => 'c`">>
                   ])
+    , ?TYPE_ERROR(polymorphism_add_stateful_entrypoint,
+                  [<<?Pos(5,25)
+                     "`f` cannot be stateful because the entrypoint `f` in the interface `I` is not stateful">>
+                  ])
+    , ?TYPE_ERROR(polymorphism_change_entrypoint_to_function,
+                  [<<?Pos(6,14)
+                     "`f` must be declared as an entrypoint instead of a function in order to implement the entrypoint `f` from the interface `I`">>
+                  ])
+    , ?TYPE_ERROR(polymorphism_non_payable_contract_implement_payable,
+                  [<<?Pos(4,10)
+                     "Non-payable contract `C` cannot implement payable interface `I`">>
+                  ])
+    , ?TYPE_ERROR(polymorphism_non_payable_interface_implement_payable,
+                  [<<?Pos(4,20)
+                     "Non-payable interface `H` cannot implement payable interface `I`">>
+                  ])
+    , ?TYPE_ERROR(polymorphism_remove_payable_entrypoint,
+                  [<<?Pos(5,16)
+                     "`f` must be payable because the entrypoint `f` in the interface `I` is payable">>
+                  ])
     ].
 
 validation_test_() ->
diff --git a/test/contracts/polymorphism_add_stateful_entrypoint.aes b/test/contracts/polymorphism_add_stateful_entrypoint.aes
new file mode 100644
index 0000000..26b279c
--- /dev/null
+++ b/test/contracts/polymorphism_add_stateful_entrypoint.aes
@@ -0,0 +1,5 @@
+contract interface I =
+    entrypoint f : () => int
+
+contract C : I =
+    stateful entrypoint f() = 1
diff --git a/test/contracts/polymorphism_change_entrypoint_to_function.aes b/test/contracts/polymorphism_change_entrypoint_to_function.aes
new file mode 100644
index 0000000..38c9614
--- /dev/null
+++ b/test/contracts/polymorphism_change_entrypoint_to_function.aes
@@ -0,0 +1,6 @@
+contract interface I =
+    entrypoint f : () => int
+
+contract C : I =
+    entrypoint init() = ()
+    function f() = 1
diff --git a/test/contracts/polymorphism_non_payable_contract_implement_payable.aes b/test/contracts/polymorphism_non_payable_contract_implement_payable.aes
new file mode 100644
index 0000000..59c0fca
--- /dev/null
+++ b/test/contracts/polymorphism_non_payable_contract_implement_payable.aes
@@ -0,0 +1,5 @@
+payable contract interface I =
+    payable entrypoint f : () => int
+
+contract C : I =
+    entrypoint f() = 123
diff --git a/test/contracts/polymorphism_non_payable_interface_implement_payable.aes b/test/contracts/polymorphism_non_payable_interface_implement_payable.aes
new file mode 100644
index 0000000..3849ea5
--- /dev/null
+++ b/test/contracts/polymorphism_non_payable_interface_implement_payable.aes
@@ -0,0 +1,8 @@
+payable contract interface I =
+    payable entrypoint f : () => int
+
+contract interface H : I =
+    payable entrypoint f : () => int
+
+payable contract C : H =
+    entrypoint f() = 123
diff --git a/test/contracts/polymorphism_remove_payable_entrypoint.aes b/test/contracts/polymorphism_remove_payable_entrypoint.aes
new file mode 100644
index 0000000..b916ca1
--- /dev/null
+++ b/test/contracts/polymorphism_remove_payable_entrypoint.aes
@@ -0,0 +1,5 @@
+contract interface I =
+    payable entrypoint f : () => int
+
+contract C : I =
+    entrypoint f() = 1