Check that init doesn't read or write the state

test/aeso_compiler_tests.erl

@@ -316,4 +316,17 @@ failing_contracts() ->
         <<"Cannot pass non-zero value argument 1000 (at line 48, column 55)\nin the definition of non-stateful function fail6.">>,
         <<"Cannot pass non-zero value argument 1000 (at line 49, column 54)\nin the definition of non-stateful function fail7.">>,
         <<"Cannot pass non-zero value argument 1000 (at line 52, column 17)\nin the definition of non-stateful function fail8.">>]}
+    , {"bad_init_state_access",
+       [<<"The init function should return the initial state as its result and cannot write the state,\n"
+          "but it calls\n"
+          "  - set_state (at line 11, column 5), which calls\n"
+          "  - roundabout (at line 8, column 36), which calls\n"
+          "  - put (at line 7, column 37)">>,
+        <<"The init function should return the initial state as its result and cannot read the state,\n"
+          "but it calls\n"
+          "  - new_state (at line 12, column 5), which calls\n"
+          "  - state (at line 5, column 27)">>,
+        <<"The init function should return the initial state as its result and cannot read the state,\n"
+          "but it calls\n"
+          "  - state (at line 13, column 13)">>]}
     ].

test/contracts/bad_init_state_access.aes

@@ -0,0 +1,13 @@
+contract BadInit =
+
+  type state = int
+
+  function new_state(n) = state + n
+
+  stateful function roundabout(n) = put(n)
+  stateful function set_state(n) = roundabout(n)
+
+  stateful function init() =
+    set_state(4)
+    new_state(0)
+    state + state