diff --git a/crates/els/inlay_hint.rs b/crates/els/inlay_hint.rs
index 93f11ddb..c38cd642 100644
--- a/crates/els/inlay_hint.rs
+++ b/crates/els/inlay_hint.rs
@@ -252,7 +252,10 @@ impl<Checker: BuildRunnable> Server<Checker> {
                 // NG: f(proc:= i: T): U -> ...
                 // OK: f proc:= (i: T): U -> ...
                 let (name, col_begin) = if arg_is_lambda {
-                    (format!(" {name}"), col_begin.saturating_sub(1))
+                    (
+                        format!(" {name}"),
+                        col_begin.saturating_sub(1),
+                    )
                 } else {
                     (name.to_string(), col_begin)
                 };
diff --git a/crates/erg_compiler/context/register.rs b/crates/erg_compiler/context/register.rs
index d8887474..096d7aeb 100644
--- a/crates/erg_compiler/context/register.rs
+++ b/crates/erg_compiler/context/register.rs
@@ -11,8 +11,8 @@ use erg_common::python_util::BUILTIN_PYTHON_MODS;
 use erg_common::set::Set;
 use erg_common::traits::{Locational, Stream};
 use erg_common::vis::Visibility;
-use erg_common::Str;
 use erg_common::{enum_unwrap, get_hash, log, set};
+use erg_common::Str;
 
 use ast::{Decorator, DefId, Identifier, OperationKind, SimpleTypeSpec, VarName};
 use erg_parser::ast::{self, ConstIdentifier};
diff --git a/src/dummy.rs b/src/dummy.rs
index 7133b853..fcc05401 100644
--- a/src/dummy.rs
+++ b/src/dummy.rs
@@ -209,9 +209,14 @@ impl DummyVM {
 
 fn find_available_port() -> u16 {
     const DEFAULT_PORT: u16 = 8736;
-    let mut port = DEFAULT_PORT;
-    while TcpListener::bind(SocketAddrV4::new(Ipv4Addr::LOCALHOST, port)).is_err() {
-        port += 1;
-    }
-    port
+    TcpListener::bind(SocketAddrV4::new(Ipv4Addr::LOCALHOST, DEFAULT_PORT))
+        .is_ok()
+        .then_some(DEFAULT_PORT)
+        .unwrap_or_else(|| {
+            let socket = SocketAddrV4::new(Ipv4Addr::LOCALHOST, 0);
+            TcpListener::bind(socket)
+                .and_then(|listener| listener.local_addr())
+                .map(|sock_addr| sock_addr.port())
+                .expect("No free port found.")
+        })
 }