Fix self-referential Display impl

zebra-consensus/src/primitives/halo2.rs

@@ -123,15 +123,17 @@ impl From<zebra_chain::orchard::ShieldedData> for Item {
 #[derive(Clone, Debug, Error, Eq, PartialEq)]
 pub enum Halo2Error {
     /// The constraint system is not satisfied.
-    // #[default]
     ConstraintSystemFailure,
     /// Catchall for now until https://github.com/zcash/halo2/pull/394 is merged
     Other,
 }
 
 impl fmt::Display for Halo2Error {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
-        write!(f, "{}", self)
+        match self {
+            Halo2Error::ConstraintSystemFailure => write!(f, "Constraint system failure"),
+            _ => write!(f, "Unknown Halo2 error"),
+        }
     }
 }