Fix literal test and useless property computation

Author: shilangyu

regex-syntax/src/hir/literal.rs

@@ -2458,13 +2458,13 @@ mod tests {
     #[test]
     #[ignore = "Missing parser support for lookaround"]
     fn lookaround() {
-        assert_eq!(exact(["ab"]), e(r"a(?<=qwe)b"));
+        assert_eq!(exact(["ab"]), e(r"a(?<=qwa)b"));
         assert_eq!(exact(["ab"]), e(r"a(?<!qwe)b"));
 
         assert_eq!(exact(["ab"]), e(r"(?<=qwe)ab"));
         assert_eq!(exact(["ab"]), e(r"(?<!qwe)ab"));
 
-        assert_eq!(exact(["ab"]), e(r"ab(?<=qwe)"));
+        assert_eq!(exact(["ab"]), e(r"ab(?<=qab)"));
         assert_eq!(exact(["ab"]), e(r"ab(?<!qwe)"));
 
         let expected = (seq([I("aZ"), E("ab")]), seq([I("Zb"), E("ab")]));

regex-syntax/src/hir/mod.rs

@@ -2569,8 +2569,6 @@ impl Properties {
             maximum_len: Some(0),
             literal: false,
             alternation_literal: false,
-            explicit_captures_len: sub_p.explicit_captures_len(),
-            static_explicit_captures_len: sub_p.static_explicit_captures_len(),
             ..*sub_p.0.clone()
         };
         Properties(Box::new(inner))