[clippy] use variables directly in format strings

Author: nickfarrow

schnorr_fun/src/frost/share.rs

@@ -489,7 +489,7 @@ mod share_backup {
                 if share_index_u32 >= HUMAN_READABLE_THRESHOLD {
                     prop_assert!(backup.starts_with("frost1"));
                 } else {
-                    assert!(backup.starts_with(&format!("frost[{}]", share_index_u32)));
+                    assert!(backup.starts_with(&format!("frost[{share_index_u32}]")));
                 }
 
                 prop_assert_eq!(SecretShare::from_bech32_backup(&backup), Ok(secret_share))

secp256kfun/tests/test_hash_to_curve.rs

@@ -44,14 +44,12 @@ fn test_hash_to_curve_sswu_test_vectors() {
         assert_eq!(
             &x_bytes[..],
             &expected_x[..],
-            "Test vector {} failed: x coordinate mismatch",
-            i
+            "Test vector {i} failed: x coordinate mismatch",
         );
         assert_eq!(
             &y_bytes[..],
             &expected_y[..],
-            "Test vector {} failed: y coordinate mismatch",
-            i
+            "Test vector {i} failed: y coordinate mismatch",
         );
     }
 }
@@ -149,8 +147,7 @@ fn test_hash_to_curve_test_vectors() {
 
         assert_eq!(
             actual_bytes, expected_bytes,
-            "Test vector {} failed: msg={:?}",
-            i, msg
+            "Test vector {i} failed: msg={msg:?}",
         );
 
         // Verify determinism
@@ -209,8 +206,7 @@ fn test_hash_to_curve_rfc9381_tai() {
 
         assert_eq!(
             actual_bytes, expected_bytes,
-            "Test vector {} failed: msg={:?}, salt={:?}",
-            i, msg, salt
+            "Test vector {i} failed: msg={msg:?}, salt={salt:?}",
         );
 
         // Verify determinism