diff --git a/rslib/src/scheduler/fsrs/simulator.rs b/rslib/src/scheduler/fsrs/simulator.rs
index 10d048210..595f2a028 100644
--- a/rslib/src/scheduler/fsrs/simulator.rs
+++ b/rslib/src/scheduler/fsrs/simulator.rs
@@ -16,6 +16,7 @@ use rand::rngs::StdRng;
 use rand::Rng;
 
 use crate::card::CardQueue;
+use crate::card::CardType;
 use crate::card::FsrsMemoryState;
 use crate::prelude::*;
 use crate::scheduler::states::fuzz::constrained_fuzz_bounds;