diff --git a/crates/shadowsocks-service/src/acl/mod.rs b/crates/shadowsocks-service/src/acl/mod.rs
index 96a37bb3..85389490 100644
--- a/crates/shadowsocks-service/src/acl/mod.rs
+++ b/crates/shadowsocks-service/src/acl/mod.rs
@@ -195,7 +195,7 @@ impl ParsingRules {
     }
 
     fn compile_regex(name: &'static str, regex_rules: Vec<String>) -> io::Result<RegexSet> {
-        const REGEX_SIZE_LIMIT: usize = usize::max_value();
+        const REGEX_SIZE_LIMIT: usize = usize::MAX;
         RegexSetBuilder::new(regex_rules)
             .size_limit(REGEX_SIZE_LIMIT)
             .unicode(false)
diff --git a/crates/shadowsocks/src/relay/socks5.rs b/crates/shadowsocks/src/relay/socks5.rs
index 5bd2965a..925fa5b7 100644
--- a/crates/shadowsocks/src/relay/socks5.rs
+++ b/crates/shadowsocks/src/relay/socks5.rs
@@ -9,7 +9,6 @@ use std::{
     net::{Ipv4Addr, Ipv6Addr, SocketAddr, SocketAddrV4, SocketAddrV6, ToSocketAddrs},
     slice,
     str::FromStr,
-    u8,
     vec,
 };
 
@@ -422,7 +421,7 @@ fn write_ipv6_address<B: BufMut>(addr: &SocketAddrV6, buf: &mut B) {
 }
 
 fn write_domain_name_address<B: BufMut>(dnaddr: &str, port: u16, buf: &mut B) {
-    assert!(dnaddr.len() <= u8::max_value() as usize);
+    assert!(dnaddr.len() <= u8::MAX as usize);
 
     buf.put_u8(consts::SOCKS5_ADDR_TYPE_DOMAIN_NAME);
     assert!(