diff --git a/src/expr.rs b/src/expr.rs
index dde0a3ffd3..ae723242eb 100644
--- a/src/expr.rs
+++ b/src/expr.rs
@@ -1663,7 +1663,7 @@ pub(crate) mod parsing {
             }
             Ok(expr)
         } else {
-            Err(input.error("expected expression"))
+            Err(input.error("expected an expression"))
         }
     }