correct style failures

src/parser/ast.rs

@@ -327,8 +327,9 @@ impl DoubleQuotes {
     }
 }
 
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone, Copy, Default)]
 pub enum Unknown {
+    #[default]
     Error,
     Fail,
     Warn,
@@ -348,13 +349,6 @@ impl Unknown {
     }
 }
 
-impl Default for Unknown {
-    #[inline]
-    fn default() -> Self {
-        Unknown::Error
-    }
-}
-
 pub fn default_op_dir() -> OpDir {
     let mut op_dir = OpDir::with_hasher(FxBuildHasher::default());