fix(parser): Don't panic when subcommands conflict with groups

Mentioned in #6182

Author: epage

clap_builder/src/parser/parser.rs

@@ -483,7 +483,8 @@ impl<'cmd> Parser<'cmd> {
                     pos_sc_name.clone(),
                     matcher
                         .arg_ids()
-                        .map(|id| self.cmd.find(id).unwrap().to_string())
+                        // skip groups
+                        .filter_map(|id| self.cmd.find(id).map(|a| a.to_string()))
                         .collect(),
                     Usage::new(self.cmd).create_usage_with_title(&[]),
                 ));

tests/builder/conflicts.rs

@@ -990,7 +990,6 @@ fn args_negate_subcommands_two_levels() {
 }
 
 #[test]
-#[should_panic]
 fn group_conrflicts_with_subcommands() {
     let c = Command::new("test")
         .args_conflicts_with_subcommands(true)