diff --git a/cli/diff.rs b/cli/diff.rs
index cc516d94ce..50ba7c6337 100644
--- a/cli/diff.rs
+++ b/cli/diff.rs
@@ -106,7 +106,7 @@ pub fn diff(orig_text: &str, edit_text: &str) -> Result<String, fmt::Error> {
         let split = s.split('\n').enumerate();
         for (i, s) in split {
           if i > 0 {
-            orig.push_str("\n");
+            orig.push('\n');
           }
           orig.push_str(&fmt_rem_text_highlight(s));
         }
@@ -116,7 +116,7 @@ pub fn diff(orig_text: &str, edit_text: &str) -> Result<String, fmt::Error> {
         let split = s.split('\n').enumerate();
         for (i, s) in split {
           if i > 0 {
-            edit.push_str("\n");
+            edit.push('\n');
           }
           edit.push_str(&fmt_add_text_highlight(s));
         }
diff --git a/cli/http_cache.rs b/cli/http_cache.rs
index 240d44adb6..b936d11e8d 100644
--- a/cli/http_cache.rs
+++ b/cli/http_cache.rs
@@ -58,7 +58,7 @@ pub fn url_to_filename(url: &Url) -> PathBuf {
 
   let mut rest_str = url.path().to_string();
   if let Some(query) = url.query() {
-    rest_str.push_str("?");
+    rest_str.push('?');
     rest_str.push_str(query);
   }
   // NOTE: fragment is omitted on purpose - it's not taken into
diff --git a/cli/main.rs b/cli/main.rs
index 5f79464485..37d5edc580 100644
--- a/cli/main.rs
+++ b/cli/main.rs
@@ -664,7 +664,7 @@ pub fn main() {
   .format(|buf, record| {
     let mut target = record.target().to_string();
     if let Some(line_no) = record.line() {
-      target.push_str(":");
+      target.push(':');
       target.push_str(&line_no.to_string());
     }
     if record.level() >= Level::Info {