diff --git a/src/context_diff.rs b/src/context_diff.rs
index 9c567d8..f0c1caa 100644
--- a/src/context_diff.rs
+++ b/src/context_diff.rs
@@ -450,7 +450,7 @@ mod tests {
                                     .stdin(File::open(&format!("{target}/ab.diff")).unwrap())
                                     .output()
                                     .unwrap();
-                                assert!(output.status.success(), "{:?}", output);
+                                assert!(output.status.success(), "{output:?}");
                                 //println!("{}", String::from_utf8_lossy(&output.stdout));
                                 //println!("{}", String::from_utf8_lossy(&output.stderr));
                                 let alef = fs::read(&format!("{target}/alef")).unwrap();
@@ -531,7 +531,7 @@ mod tests {
                                     .stdin(File::open(&format!("{target}/ab_.diff")).unwrap())
                                     .output()
                                     .unwrap();
-                                assert!(output.status.success(), "{:?}", output);
+                                assert!(output.status.success(), "{output:?}");
                                 //println!("{}", String::from_utf8_lossy(&output.stdout));
                                 //println!("{}", String::from_utf8_lossy(&output.stderr));
                                 let alef = fs::read(&format!("{target}/alef_")).unwrap();
@@ -615,7 +615,7 @@ mod tests {
                                     .stdin(File::open(&format!("{target}/abx.diff")).unwrap())
                                     .output()
                                     .unwrap();
-                                assert!(output.status.success(), "{:?}", output);
+                                assert!(output.status.success(), "{output:?}");
                                 //println!("{}", String::from_utf8_lossy(&output.stdout));
                                 //println!("{}", String::from_utf8_lossy(&output.stderr));
                                 let alef = fs::read(&format!("{target}/alefx")).unwrap();
@@ -702,7 +702,7 @@ mod tests {
                                     .stdin(File::open(&format!("{target}/abr.diff")).unwrap())
                                     .output()
                                     .unwrap();
-                                assert!(output.status.success(), "{:?}", output);
+                                assert!(output.status.success(), "{output:?}");
                                 //println!("{}", String::from_utf8_lossy(&output.stdout));
                                 //println!("{}", String::from_utf8_lossy(&output.stderr));
                                 let alef = fs::read(&format!("{target}/alefr")).unwrap();
diff --git a/src/ed_diff.rs b/src/ed_diff.rs
index 1be37a5..d2d8499 100644
--- a/src/ed_diff.rs
+++ b/src/ed_diff.rs
@@ -133,7 +133,7 @@ pub fn diff(expected: &[u8], actual: &[u8], params: &Params) -> Result<Vec<u8>,
                 expected_count + line_number_expected - 1
             )
             .unwrap(),
-            (1, _) => writeln!(&mut output, "{}c", line_number_expected).unwrap(),
+            (1, _) => writeln!(&mut output, "{line_number_expected}c").unwrap(),
             _ => writeln!(
                 &mut output,
                 "{},{}c",
@@ -241,7 +241,7 @@ mod tests {
                                     .stdin(File::open("target/ab.ed").unwrap())
                                     .output()
                                     .unwrap();
-                                assert!(output.status.success(), "{:?}", output);
+                                assert!(output.status.success(), "{output:?}");
                                 //println!("{}", String::from_utf8_lossy(&output.stdout));
                                 //println!("{}", String::from_utf8_lossy(&output.stderr));
                                 let alef = fs::read(&format!("{target}/alef")).unwrap();
@@ -312,7 +312,7 @@ mod tests {
                                     .stdin(File::open("target/ab_.ed").unwrap())
                                     .output()
                                     .unwrap();
-                                assert!(output.status.success(), "{:?}", output);
+                                assert!(output.status.success(), "{output:?}");
                                 //println!("{}", String::from_utf8_lossy(&output.stdout));
                                 //println!("{}", String::from_utf8_lossy(&output.stderr));
                                 let alef = fs::read("target/alef_").unwrap();
@@ -389,7 +389,7 @@ mod tests {
                                     .stdin(File::open("target/abr.ed").unwrap())
                                     .output()
                                     .unwrap();
-                                assert!(output.status.success(), "{:?}", output);
+                                assert!(output.status.success(), "{output:?}");
                                 //println!("{}", String::from_utf8_lossy(&output.stdout));
                                 //println!("{}", String::from_utf8_lossy(&output.stderr));
                                 let alef = fs::read(&format!("{target}/alefr")).unwrap();
diff --git a/src/main.rs b/src/main.rs
index dab0eff..a19e646 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -35,7 +35,7 @@ fn main() -> ExitCode {
                 "Files {} and {} are identical",
                 params.from.to_string_lossy(),
                 params.to.to_string_lossy(),
-            )
+            );
         }
     };
     if same_file::is_same_file(&params.from, &params.to).unwrap_or(false) {
diff --git a/src/normal_diff.rs b/src/normal_diff.rs
index cfa389c..d6f8297 100644
--- a/src/normal_diff.rs
+++ b/src/normal_diff.rs
@@ -155,9 +155,7 @@ pub fn diff(expected: &[u8], actual: &[u8], params: &Params) -> Vec<u8> {
                 // 'c' stands for "Change lines"
                 // exactly one line replaced by one line
                 &mut output,
-                "{}c{}",
-                line_number_expected,
-                line_number_actual
+                "{line_number_expected}c{line_number_actual}"
             )
             .unwrap(),
             (1, _) => writeln!(
@@ -293,7 +291,7 @@ mod tests {
                                     .stdin(File::open(&format!("{target}/ab.diff")).unwrap())
                                     .output()
                                     .unwrap();
-                                assert!(output.status.success(), "{:?}", output);
+                                assert!(output.status.success(), "{output:?}");
                                 //println!("{}", String::from_utf8_lossy(&output.stdout));
                                 //println!("{}", String::from_utf8_lossy(&output.stderr));
                                 let alef = fs::read(&format!("{target}/alef")).unwrap();
@@ -386,7 +384,7 @@ mod tests {
                                         .stdin(File::open(&format!("{target}/abn.diff")).unwrap())
                                         .output()
                                         .unwrap();
-                                    assert!(output.status.success(), "{:?}", output);
+                                    assert!(output.status.success(), "{output:?}");
                                     //println!("{}", String::from_utf8_lossy(&output.stdout));
                                     //println!("{}", String::from_utf8_lossy(&output.stderr));
                                     let alef = fs::read(&format!("{target}/alefn")).unwrap();
@@ -459,7 +457,7 @@ mod tests {
                                     .stdin(File::open(&format!("{target}/ab_.diff")).unwrap())
                                     .output()
                                     .unwrap();
-                                assert!(output.status.success(), "{:?}", output);
+                                assert!(output.status.success(), "{output:?}");
                                 //println!("{}", String::from_utf8_lossy(&output.stdout));
                                 //println!("{}", String::from_utf8_lossy(&output.stderr));
                                 let alef = fs::read(&format!("{target}/alef_")).unwrap();
@@ -537,7 +535,7 @@ mod tests {
                                     .stdin(File::open(&format!("{target}/abr.diff")).unwrap())
                                     .output()
                                     .unwrap();
-                                assert!(output.status.success(), "{:?}", output);
+                                assert!(output.status.success(), "{output:?}");
                                 //println!("{}", String::from_utf8_lossy(&output.stdout));
                                 //println!("{}", String::from_utf8_lossy(&output.stderr));
                                 let alef = fs::read(&format!("{target}/alefr")).unwrap();
diff --git a/src/params.rs b/src/params.rs
index 7017646..74e8d15 100644
--- a/src/params.rs
+++ b/src/params.rs
@@ -99,7 +99,7 @@ pub fn parse_params<I: IntoIterator<Item = OsString>>(opts: I) -> Result<Params,
                 .as_str();
             params.tabsize = match tabsize_str.parse::<usize>() {
                 Ok(num) => num,
-                Err(_) => return Err(format!("invalid tabsize «{}»", tabsize_str)),
+                Err(_) => return Err(format!("invalid tabsize «{tabsize_str}»")),
             };
             continue;
         }
diff --git a/src/unified_diff.rs b/src/unified_diff.rs
index 3af51c2..97ce764 100644
--- a/src/unified_diff.rs
+++ b/src/unified_diff.rs
@@ -494,7 +494,7 @@ mod tests {
                                     .unwrap();
                                 println!("{}", String::from_utf8_lossy(&output.stdout));
                                 println!("{}", String::from_utf8_lossy(&output.stderr));
-                                assert!(output.status.success(), "{:?}", output);
+                                assert!(output.status.success(), "{output:?}");
                                 let alef = fs::read(&format!("{target}/alef")).unwrap();
                                 assert_eq!(alef, bet);
                             }
@@ -592,7 +592,7 @@ mod tests {
                                         .stdin(File::open(&format!("{target}/abn.diff")).unwrap())
                                         .output()
                                         .unwrap();
-                                    assert!(output.status.success(), "{:?}", output);
+                                    assert!(output.status.success(), "{output:?}");
                                     //println!("{}", String::from_utf8_lossy(&output.stdout));
                                     //println!("{}", String::from_utf8_lossy(&output.stderr));
                                     let alef = fs::read(&format!("{target}/alefn")).unwrap();
@@ -688,7 +688,7 @@ mod tests {
                                         .stdin(File::open(&format!("{target}/ab_.diff")).unwrap())
                                         .output()
                                         .unwrap();
-                                    assert!(output.status.success(), "{:?}", output);
+                                    assert!(output.status.success(), "{output:?}");
                                     //println!("{}", String::from_utf8_lossy(&output.stdout));
                                     //println!("{}", String::from_utf8_lossy(&output.stderr));
                                     let alef = fs::read(&format!("{target}/alef_")).unwrap();
@@ -769,7 +769,7 @@ mod tests {
                                     .stdin(File::open(&format!("{target}/abx.diff")).unwrap())
                                     .output()
                                     .unwrap();
-                                assert!(output.status.success(), "{:?}", output);
+                                assert!(output.status.success(), "{output:?}");
                                 //println!("{}", String::from_utf8_lossy(&output.stdout));
                                 //println!("{}", String::from_utf8_lossy(&output.stderr));
                                 let alef = fs::read(&format!("{target}/alefx")).unwrap();
@@ -855,7 +855,7 @@ mod tests {
                                     .stdin(File::open(&format!("{target}/abr.diff")).unwrap())
                                     .output()
                                     .unwrap();
-                                assert!(output.status.success(), "{:?}", output);
+                                assert!(output.status.success(), "{output:?}");
                                 //println!("{}", String::from_utf8_lossy(&output.stdout));
                                 //println!("{}", String::from_utf8_lossy(&output.stderr));
                                 let alef = fs::read(&format!("{target}/alefr")).unwrap();
diff --git a/src/utils.rs b/src/utils.rs
index 94d950f..c503fd9 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -10,6 +10,7 @@ use unicode_width::UnicodeWidthStr;
 /// Replace tabs by spaces in the input line.
 /// Correctly handle multi-bytes characters.
 /// This assumes that line does not contain any line breaks (if it does, the result is undefined).
+#[must_use]
 pub fn do_expand_tabs(line: &[u8], tabsize: usize) -> Vec<u8> {
     let tab = b'\t';
     let ntabs = line.iter().filter(|c| **c == tab).count();