diff --git a/src/parser/arg_matcher.rs b/src/parser/arg_matcher.rs
index 875c9241479..071e3b272db 100644
--- a/src/parser/arg_matcher.rs
+++ b/src/parser/arg_matcher.rs
@@ -32,7 +32,7 @@ impl ArgMatcher {
                 #[cfg(debug_assertions)]
                 valid_subcommands: _cmd
                     .get_subcommands()
-                    .map(|sc| sc.get_name().to_owned())
+                    .map(|sc| sc.get_name_str().clone())
                     .collect(),
                 ..Default::default()
             },
diff --git a/src/parser/matches/arg_matches.rs b/src/parser/matches/arg_matches.rs
index 2d93e92d8ed..cfbae26ef1f 100644
--- a/src/parser/matches/arg_matches.rs
+++ b/src/parser/matches/arg_matches.rs
@@ -66,7 +66,7 @@ pub struct ArgMatches {
     #[cfg(debug_assertions)]
     pub(crate) valid_args: Vec<Id>,
     #[cfg(debug_assertions)]
-    pub(crate) valid_subcommands: Vec<String>,
+    pub(crate) valid_subcommands: Vec<Str>,
     pub(crate) args: FlatMap<Id, MatchedArg>,
     pub(crate) subcommand: Option<Box<SubCommand>>,
 }
@@ -924,8 +924,7 @@ impl ArgMatches {
     pub fn is_valid_subcommand(&self, _name: &str) -> bool {
         #[cfg(debug_assertions)]
         {
-            let _name = _name.to_owned();
-            _name == String::default() || self.valid_subcommands.contains(&_name)
+            _name.is_empty() || self.valid_subcommands.iter().any(|s| *s == _name)
         }
         #[cfg(not(debug_assertions))]
         {
@@ -1094,8 +1093,7 @@ impl ArgMatches {
     fn verify_arg(&self, _arg: &str) -> Result<(), MatchesError> {
         #[cfg(debug_assertions)]
         {
-            let _arg = Id::from(_arg.to_owned());
-            if _arg == Id::EXTERNAL || self.valid_args.contains(&_arg) {
+            if _arg == Id::EXTERNAL || self.valid_args.iter().any(|s| *s == _arg) {
             } else {
                 debug!(
                     "`{:?}` is not an id of an argument or a group.\n\
@@ -1114,8 +1112,7 @@ impl ArgMatches {
     fn get_arg<'s>(&'s self, arg: &str) -> Option<&'s MatchedArg> {
         #[cfg(debug_assertions)]
         {
-            let arg = Id::from(arg.to_owned());
-            if arg == Id::EXTERNAL || self.valid_args.contains(&arg) {
+            if arg == Id::EXTERNAL || self.valid_args.iter().any(|s| *s == arg) {
             } else {
                 panic!(
                     "`{:?}` is not an id of an argument or a group.\n\
@@ -1134,8 +1131,7 @@ impl ArgMatches {
     fn get_subcommand(&self, name: &str) -> Option<&SubCommand> {
         #[cfg(debug_assertions)]
         {
-            let name = name.to_owned();
-            if name == String::default() || self.valid_subcommands.contains(&name) {
+            if name.is_empty() || self.valid_subcommands.iter().any(|s| *s == name) {
             } else {
                 panic!("`{}` is not a name of a subcommand.", name);
             }