Fix a warning

Author: egli

src/translator/match_pattern.rs

@@ -16,8 +16,8 @@ impl AST {
             Pattern::Any => AST::Any,
             Pattern::Set(hash_set) => AST::Set(hash_set.clone()),
             Pattern::Attributes(hash_set) => AST::from_attributes(hash_set, ctx),
-            Pattern::Group(vec) => AST::NotImplemented,
-            Pattern::Negate(pattern) => AST::NotImplemented,
+            Pattern::Group(_vec) => AST::NotImplemented,
+            Pattern::Negate(_pattern) => AST::NotImplemented,
             Pattern::Optional(pattern) => AST::Optional(Box::new(AST::from_pattern(pattern, ctx))),
             Pattern::ZeroOrMore(pattern) => {
                 AST::ZeroOrMore(Box::new(AST::from_pattern(pattern, ctx)))