[tests] Add a test for invalid use of opaque resources

tests/modules/opaque_resource_2.build

@@ -0,0 +1,9 @@
+# This is free and unencumbered software released into the public domain.
+# See ../LICENSE.unlicense
+
+# PLZTEST type compile_failure 
+
+[opaque_resource_2]
+type = program
+modules = [OpaqueResource2, OpaqueResource]
+

tests/modules/opaque_resource_2.exp

@@ -0,0 +1,2 @@
+opaque_resource_2.p:22: One or more resources needed for this call is
+                        unavailable in this function

tests/modules/opaque_resource_2.p

@@ -0,0 +1,28 @@
+/*
+ * vim: ft=plasma
+ * This is free and unencumbered software released into the public domain.
+ * See ../LICENSE.unlicense
+ */
+
+module OpaqueResource2
+
+import OpaqueResource as OR
+
+entrypoint
+func test() uses IO -> Int {
+    var s = test2!("Bob")
+    print!(s ++ "\n")
+
+    return 0
+}
+
+func test2(s : String) uses OR.Res1 -> String {
+    // Calling test3 directly is illegal. although Res2 comes from Res1 this
+    // module doesn't know that because Res2 is opaque.
+    return test3!(s)
+}
+
+func test3(s : String) uses OR.Res2 -> String {
+    return "Hi " ++ s ++ "."
+}
+