Add test for implementing multiple interfaces

test/aeso_compiler_tests.erl

@@ -203,6 +203,7 @@ compilable_contracts() ->
      "patterns_guards",
      "pipe_operator",
      "contract_polymorphism",
+     "contract_polymorphism_multi_interface",
      "contract_interface_polymorphism",
      "test" % Custom general-purpose test file. Keep it last on the list.
     ].

test/contracts/contract_polymorphism_multi_interface.aes

@@ -0,0 +1,9 @@
+contract interface I =
+    entrypoint f : () => int
+
+contract interface J =
+    entrypoint g : () => char
+
+contract C : I, J =
+    entrypoint f() = 1
+    entrypoint g() = 'c'