Fixes group conflicting if two args with default values

src/parse/validator.rs

@@ -277,7 +277,7 @@ impl<'help, 'app, 'parser> Validator<'help, 'app, 'parser> {
                             .app
                             .unroll_args_in_group(&g.id)
                             .iter()
-                            .filter(|&a| matcher.contains(a))
+                            .filter(|&a| matcher.contains(a) && !matcher.is_default_value(a))
                             .count()
                             > 1
                     };

tests/conflicts.rs

@@ -285,6 +285,26 @@ fn group_in_conflicts_with() {
     assert_eq!(m.value_of("opt"), Some("default"));
     assert!(m.is_present("flag"));
 }
+
+#[test]
+fn group_conflicts_with_default_value() {
+    let result = App::new("conflict")
+        .arg(
+            Arg::new("opt")
+                .long("opt")
+                .default_value("default")
+                .group("one"),
+        )
+        .arg(Arg::new("flag").long("flag").group("one"))
+        .try_get_matches_from(vec!["myprog", "--flag"]);
+
+    assert!(result.is_ok(), "{:?}", result.unwrap());
+    let m = result.unwrap();
+
+    assert_eq!(m.value_of("opt"), Some("default"));
+    assert!(m.is_present("flag"));
+}
+
 #[test]
 fn group_conflicts_with_default_arg() {
     let result = App::new("conflict")