skip error dumping

fuzzers/FRET/src/systemstate/feedbacks.rs

@@ -292,6 +292,8 @@ where
     where
         EM: EventFirer<State = S>,
         OT: ObserversTuple<S>
+    {
+        #[cfg(feature = "trace_stg")]
         {
             let observer = observers.match_name::<QemuSystemStateObserver<S::Input>>("systemstate")
                 .expect("QemuSystemStateObserver not found");
@@ -302,7 +304,12 @@ where
                     self.max_reports = Some(m-1);
                 }
             }
-        Ok(self.dump_case&&is_err)
+            return Ok(self.dump_case&&is_err);
+        }
+        #[cfg(not(feature = "trace_stg"))]
+        {
+            return Ok(false);
+        }
     }
     /// Append to the testcase the generated metadata in case of a new corpus item
     #[inline]