diff --git a/parse-display-derive/src/format_syntax.rs b/parse-display-derive/src/format_syntax.rs
index af6596e..9a6eac1 100644
--- a/parse-display-derive/src/format_syntax.rs
+++ b/parse-display-derive/src/format_syntax.rs
@@ -433,6 +433,6 @@ mod tests {
     }
 
     fn assert_ps<'a>(s: &'a str, ps: FormatSpec<'a>) {
-        assert_eq!(FormatSpec::parse(s), Ok(ps), "input : {}", s);
+        assert_eq!(FormatSpec::parse(s), Ok(ps), "input : {s}");
     }
 }
diff --git a/parse-display-derive/src/lib.rs b/parse-display-derive/src/lib.rs
index ca3ea6f..4eff17f 100644
--- a/parse-display-derive/src/lib.rs
+++ b/parse-display-derive/src/lib.rs
@@ -338,7 +338,7 @@ impl<'a> ParserBuilder<'a> {
                 key.replace('.', "_")
             };
             let key = REGEX_NUMBER.replace(&key, "_$0");
-            format!("(?P<{}>", key)
+            format!("(?P<{key}>")
         });
         if let Err(e) = regex_syntax::ast::parse::Parser::new().parse(&text_debug) {
             bail!(s.span(), "{}", e)
@@ -353,7 +353,7 @@ impl<'a> ParserBuilder<'a> {
             if name == CAPTURE_NAME_EMPTY {
                 has_capture_empty = true;
             }
-            Ok(format!("(?P<{}>", name))
+            Ok(format!("(?P<{name}>"))
         })?;
 
         if has_capture_empty {
@@ -398,7 +398,7 @@ impl<'a> ParserBuilder<'a> {
                     }
                     let c = self.set_capture(context, &keys, format.span)?;
                     self.parse_format
-                        .push_hir(to_hir(&format!("(?P<{}>(?s:.*?))", c)));
+                        .push_hir(to_hir(&format!("(?P<{c}>(?s:.*?))")));
                 }
             }
         }
@@ -1373,16 +1373,16 @@ impl FieldKey {
     fn to_member(&self) -> Member {
         match self {
             FieldKey::Named(s) => Member::Named(format_ident!("r#{}", s)),
-            FieldKey::Unnamed(idx) => Member::Unnamed(parse_str(&format!("{}", idx)).unwrap()),
+            FieldKey::Unnamed(idx) => Member::Unnamed(parse_str(&format!("{idx}")).unwrap()),
         }
     }
     fn binding_var(&self) -> Ident {
-        parse_str(&format!("_value_{}", self)).unwrap()
+        parse_str(&format!("_value_{self}")).unwrap()
     }
     fn new_arg_var(&self) -> Ident {
         match self {
             Self::Named(s) => parse_str(s),
-            Self::Unnamed(idx) => parse_str(&format!("_{}", idx)),
+            Self::Unnamed(idx) => parse_str(&format!("_{idx}")),
         }
         .unwrap()
     }
@@ -1390,8 +1390,8 @@ impl FieldKey {
 impl std::fmt::Display for FieldKey {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
         match self {
-            FieldKey::Named(s) => write!(f, "{}", s),
-            FieldKey::Unnamed(idx) => write!(f, "{}", idx),
+            FieldKey::Named(s) => write!(f, "{s}"),
+            FieldKey::Unnamed(idx) => write!(f, "{idx}"),
         }
     }
 }
@@ -1419,7 +1419,7 @@ fn join<T: std::fmt::Display>(s: impl IntoIterator<Item = T>, sep: &str) -> Stri
     let mut sep_current = "";
     let mut buf = String::new();
     for i in s.into_iter() {
-        write!(&mut buf, "{}{}", sep_current, i).unwrap();
+        write!(&mut buf, "{sep_current}{i}").unwrap();
         sep_current = sep;
     }
     buf
@@ -1446,11 +1446,11 @@ fn field_of<'a, 'b>(
 
 const CAPTURE_NAME_EMPTY: &str = "empty";
 fn capture_name(idx: usize) -> String {
-    format!("value_{}", idx)
+    format!("value_{idx}")
 }
 
 fn build_parse_capture_expr(field_name: &str, capture_name: &str) -> TokenStream {
-    let msg = format!("field `{}` parse failed.", field_name);
+    let msg = format!("field `{field_name}` parse failed.");
     quote! {
         c.name(#capture_name)
             .map_or("", |m| m.as_str())
diff --git a/parse-display-derive/src/syn_utils.rs b/parse-display-derive/src/syn_utils.rs
index 2e65623..9180e2e 100644
--- a/parse-display-derive/src/syn_utils.rs
+++ b/parse-display-derive/src/syn_utils.rs
@@ -171,7 +171,7 @@ pub fn impl_trait_result(
 ) -> Result<TokenStream> {
     let ts = impl_trait(input, trait_path, wheres, contents);
     if dump {
-        panic!("macro output:\n{}", ts);
+        panic!("macro output:\n{ts}");
     }
     Ok(ts)
 }
diff --git a/parse-display-tests/tests/both.rs b/parse-display-tests/tests/both.rs
index b7c5d61..e14f238 100644
--- a/parse-display-tests/tests/both.rs
+++ b/parse-display-tests/tests/both.rs
@@ -26,11 +26,11 @@ fn assert_both<T: Display + FromStr + PartialEq + Debug>(s: &str, value: T)
 where
     <T as FromStr>::Err: Display,
 {
-    let value_display = format!("{}", value);
+    let value_display = format!("{value}");
     assert_eq!(value_display, s);
 
     match s.parse::<T>() {
-        Ok(a) => assert_eq!(a, value, "input = \"{}\"", s),
-        Err(e) => panic!("\"{}\" parse failed. ({})", s, e),
+        Ok(a) => assert_eq!(a, value, "input = \"{s}\""),
+        Err(e) => panic!("\"{s}\" parse failed. ({e})"),
     }
 }
diff --git a/parse-display-tests/tests/display.rs b/parse-display-tests/tests/display.rs
index e422c1d..bd29e8e 100644
--- a/parse-display-tests/tests/display.rs
+++ b/parse-display-tests/tests/display.rs
@@ -972,6 +972,6 @@ fn format_spec_is_empty() {
 }
 
 fn assert_display<T: core::fmt::Display>(value: T, display: &str) {
-    let value_display = alloc::format!("{}", value);
+    let value_display = alloc::format!("{value}");
     assert_eq!(value_display, display);
 }
diff --git a/parse-display-tests/tests/from_str.rs b/parse-display-tests/tests/from_str.rs
index 8cc3d53..075dcd2 100644
--- a/parse-display-tests/tests/from_str.rs
+++ b/parse-display-tests/tests/from_str.rs
@@ -1078,15 +1078,12 @@ where
     <T as FromStr>::Err: Display,
 {
     match s.parse::<T>() {
-        Ok(a) => assert_eq!(a, value, "input = \"{}\"", s),
-        Err(e) => panic!("\"{}\" parse failed. ({})", s, e),
+        Ok(a) => assert_eq!(a, value, "input = \"{s}\""),
+        Err(e) => panic!("\"{s}\" parse failed. ({e})"),
     }
 }
 fn assert_from_str_err<T: FromStr + Debug>(s: &str) {
     if let Ok(a) = s.parse::<T>() {
-        panic!(
-            "from_str(\"{}\") should return Err. but return `{:?}`.",
-            s, a
-        );
+        panic!("from_str(\"{s}\") should return Err. but return `{a:?}`.");
     }
 }