Fix unchecked builds.

src/engine_api.rs

@@ -1074,7 +1074,7 @@ impl Engine {
                     Some(Ok(module_ast)) => {
                         collect_imports(&module_ast, &mut resolver, &mut imports)
                     }
-                    Some(err @ Err(_)) => return err,
+                    Some(err) => return err,
                     None => (),
                 }