generate a module trait and call it

src/lib.rs

@@ -7,17 +7,21 @@ pub mod test {
         value_errors: Vec<::memory::GuestValueError>,
     }
 
+    impl foo::Foo for WasiCtx {
+        fn bar(&mut self, an_int: u32, an_float: f32) -> Result<(), types::Errno> {
+            println!("BAR: {} {}", an_int, an_float);
+            Ok(())
+        }
+    }
+
     // Errno is used as a first return value in the functions above, therefore
     // it must implement GuestError with type Context = WasiCtx.
     // The context type should let you do logging or debugging or whatever you need
     // with these errors. We just push them to vecs.
     impl ::memory::GuestError for types::Errno {
         type Context = WasiCtx;
-        fn is_success(&self) -> bool {
-            match self {
-                types::Errno::Ok => true,
-                _ => false,
-            }
+        fn success() -> types::Errno {
+            types::Errno::Ok
         }
         fn from_memory_error(e: ::memory::MemoryError, ctx: &mut WasiCtx) -> types::Errno {
             ctx.mem_errors.push(e);