Fix clippy warnings

Especially https://rust-lang.github.io/rust-clippy/master/index.html#format_push_string was a bit
more involved, review requested.

client/src/main.rs

@@ -725,7 +725,7 @@ fn delete_cidr(
     let cidr_id = prompts::delete_cidr(&cidrs, &peers, &sub_opts)?;
 
     println!("Deleting CIDR...");
-    let _ = api.http("DELETE", &*format!("/admin/cidrs/{}", cidr_id))?;
+    api.http("DELETE", &*format!("/admin/cidrs/{}", cidr_id))?;
 
     println!("CIDR deleted.");
 
@@ -801,7 +801,7 @@ fn rename_peer(
             .next()
             .ok_or_else(|| anyhow!("Peer not found."))?;
 
-        let _ = api.http_form("PUT", &format!("/admin/peers/{}", id), peer_request)?;
+        api.http_form("PUT", &format!("/admin/peers/{}", id), peer_request)?;
         log::info!("Peer renamed.");
     } else {
         log::info!("exited without renaming peer.");

server/src/main.rs

@@ -357,7 +357,7 @@ fn rename_peer(
             .into_iter()
             .find(|p| p.name == old_name)
             .ok_or_else(|| anyhow!("Peer not found."))?;
-        let _peer = db_peer.update(&conn, peer_request)?;
+        db_peer.update(&conn, peer_request)?;
     } else {
         println!("exited without creating peer.");
     }
@@ -408,7 +408,7 @@ fn delete_cidr(
     let cidr_id = prompts::delete_cidr(&cidrs, &peers, &args)?;
 
     println!("Deleting CIDR...");
-    let _ = DatabaseCidr::delete(&conn, cidr_id)?;
+    DatabaseCidr::delete(&conn, cidr_id)?;
 
     println!("CIDR deleted.");
 

wireguard-control/src/backends/kernel.rs

@@ -34,7 +34,7 @@ macro_rules! get_nla_value {
     };
 }
 
-impl<'a> TryFrom<WgAllowedIp> for AllowedIp {
+impl TryFrom<WgAllowedIp> for AllowedIp {
     type Error = io::Error;
 
     fn try_from(attrs: WgAllowedIp) -> Result<Self, Self::Error> {
@@ -88,7 +88,7 @@ impl PeerConfigBuilder {
     }
 }
 
-impl<'a> TryFrom<WgPeer> for PeerInfo {
+impl TryFrom<WgPeer> for PeerInfo {
     type Error = io::Error;
 
     fn try_from(attrs: WgPeer) -> Result<Self, Self::Error> {

wireguard-control/src/backends/userspace.rs

@@ -1,8 +1,7 @@
-use crate::{Backend, Device, DeviceUpdate, InterfaceName, PeerConfig, PeerInfo, PeerStats};
-
-use crate::Key;
+use crate::{Backend, Device, DeviceUpdate, InterfaceName, Key, PeerConfig, PeerInfo, PeerStats};
 
 use std::{
+    fmt::Write as _,
     fs,
     io::{self, prelude::*, BufReader},
     os::unix::net::UnixStream,
@@ -311,55 +310,61 @@ pub fn apply(builder: &DeviceUpdate, iface: &InterfaceName) -> io::Result<()> {
     let mut request = String::from("set=1\n");
 
     if let Some(ref k) = builder.private_key {
-        request.push_str(&format!("private_key={}\n", hex::encode(k.as_bytes())));
+        writeln!(request, "private_key={}", hex::encode(k.as_bytes())).ok();
     }
 
     if let Some(f) = builder.fwmark {
-        request.push_str(&format!("fwmark={}\n", f));
+        writeln!(request, "fwmark={}", f).ok();
     }
 
     if let Some(f) = builder.listen_port {
-        request.push_str(&format!("listen_port={}\n", f));
+        writeln!(request, "listen_port={}", f).ok();
     }
 
     if builder.replace_peers {
-        request.push_str("replace_peers=true\n");
+        writeln!(request, "replace_peers=true").ok();
     }
 
     for peer in &builder.peers {
-        request.push_str(&format!(
-            "public_key={}\n",
+        writeln!(
+            request,
+            "public_key={}",
             hex::encode(peer.public_key.as_bytes())
-        ));
+        )
+        .ok();
 
         if peer.replace_allowed_ips {
-            request.push_str("replace_allowed_ips=true\n");
+            writeln!(request, "replace_allowed_ips=true").ok();
         }
 
         if peer.remove_me {
-            request.push_str("remove=true\n");
+            writeln!(request, "remove=true").ok();
         }
 
         if let Some(ref k) = peer.preshared_key {
-            request.push_str(&format!("preshared_key={}\n", hex::encode(k.as_bytes())));
+            writeln!(request, "preshared_key={}", hex::encode(k.as_bytes())).ok();
         }
 
         if let Some(endpoint) = peer.endpoint {
-            request.push_str(&format!("endpoint={}\n", endpoint));
+            writeln!(request, "endpoint={}", endpoint).ok();
         }
 
         if let Some(keepalive_interval) = peer.persistent_keepalive_interval {
-            request.push_str(&format!(
-                "persistent_keepalive_interval={}\n",
+            writeln!(
+                request,
+                "persistent_keepalive_interval={}",
                 keepalive_interval
-            ));
+            )
+            .ok();
         }
 
         for allowed_ip in &peer.allowed_ips {
-            request.push_str(&format!(
-                "allowed_ip={}/{}\n",
+            writeln!(
+                request,
+                "allowed_ip={}/{}",
                 allowed_ip.address, allowed_ip.cidr
-            ));
+            )
+            .ok();
         }
     }