diff --git a/src/main.rs b/src/main.rs
index 3c0b4b2..f20ea39 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -111,7 +111,7 @@ fn call_think(s: &str) -> Result<String, usize> {
 			let n = lean::lean_uint64_of_nat(field) as usize;
 			Err(n)
 		} else {
-			unreachable!("Object tag > constructor")
+			unreachable!("Invalid constructor id")
 		};
 		lean::lean_dec(result_obj);
 		result