diff --git a/o1vm/src/interpreters/mips/witness.rs b/o1vm/src/interpreters/mips/witness.rs
index 3e95bbac31..8fa26522ad 100644
--- a/o1vm/src/interpreters/mips/witness.rs
+++ b/o1vm/src/interpreters/mips/witness.rs
@@ -89,6 +89,12 @@ impl LookupMultiplicities {
     }
 }
 
+impl Default for LookupMultiplicities {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 /// This structure represents the environment the virtual machine state will use
 /// to transition. This environment will be used by the interpreter. The virtual
 /// machine has access to its internal state and some external memory. In