diff --git a/src/imex.rs b/src/imex.rs
index 11bc0c748..ea4033959 100644
--- a/src/imex.rs
+++ b/src/imex.rs
@@ -350,7 +350,7 @@ async fn decrypt_setup_file<T: std::io::Read + std::io::Seek>(
 fn normalize_setup_code(s: &str) -> String {
     let mut out = String::new();
     for c in s.chars() {
-        if ('0'..='9').contains(&c) {
+        if c.is_ascii_digit() {
             out.push(c);
             if let 4 | 9 | 14 | 19 | 24 | 29 | 34 | 39 = out.len() {
                 out += "-"
diff --git a/src/key.rs b/src/key.rs
index a67cdab43..e2fbe7c82 100644
--- a/src/key.rs
+++ b/src/key.rs
@@ -387,7 +387,7 @@ impl std::str::FromStr for Fingerprint {
         let hex_repr: String = input
             .to_uppercase()
             .chars()
-            .filter(|&c| ('0'..='9').contains(&c) || ('A'..='F').contains(&c))
+            .filter(|&c| c.is_ascii_hexdigit())
             .collect();
         let v: Vec<u8> = hex::decode(&hex_repr)?;
         ensure!(v.len() == 20, "wrong fingerprint length: {}", hex_repr);
diff --git a/src/lib.rs b/src/lib.rs
index a50483843..7def6a20b 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -15,6 +15,7 @@
     clippy::unused_async
 )]
 #![allow(
+    clippy::uninlined_format_args,
     clippy::match_bool,
     clippy::mixed_read_write_in_expression,
     clippy::bool_assert_comparison,