Add error messages for bad include and nested namespace

test/aeso_compiler_tests.erl

@@ -203,4 +203,7 @@ failing_contracts() ->
            "  (gas : int, value : int) => map(string, int)">>]}
     , {"include",
         [<<"file include, line 1, column 9: includes not allowed in this context\n">>]}
+    , {"bad_include_and_ns",
+        [<<"Include of 'included.aes' at line 2, column 11\nnot allowed, include only allowed at top level.">>,
+         <<"Nested namespace not allowed\nNamespace 'Foo' at line 3, column 13 not defined at top level.">>]}
     ].

test/contracts/bad_include_and_ns.aes

@@ -0,0 +1,6 @@
+contract Bad =
+  include "included.aes"
+  namespace Foo =
+    function foo() = 42
+
+  function foo() = 43

test/contracts/include.aes

@@ -2,7 +2,6 @@ include "included.aes"
 include "../contracts/included2.aes"
 
 contract Include =
-  // include "maps.aes"
   function foo() =
     Included.foo() < Included2a.bar()