#31820 - Utilize if..let instead of single match branch

src/libstd/net/addr.rs

@@ -467,9 +467,8 @@ impl ToSocketAddrs for str {
     type Iter = vec::IntoIter<SocketAddr>;
     fn to_socket_addrs(&self) -> io::Result<vec::IntoIter<SocketAddr>> {
         // try to parse as a regular SocketAddr first
-        match self.parse().ok() {
-            Some(addr) => return Ok(vec![addr].into_iter()),
-            None => {}
+        if let Some(addr) = self.parse().ok() {
+            return Ok(vec![addr].into_iter());
         }
 
         macro_rules! try_opt {

src/libstd/net/parser.rs

@@ -66,9 +66,8 @@ impl<'a> Parser<'a> {
     fn read_or<T>(&mut self, parsers: &mut [Box<FnMut(&mut Parser) -> Option<T> + 'static>])
                -> Option<T> {
         for pf in parsers {
-            match self.read_atomically(|p: &mut Parser| pf(p)) {
-                Some(r) => return Some(r),
-                None => {}
+            if let Some(r) = self.read_atomically(|p: &mut Parser| pf(p)) {
+                return Some(r);
             }
         }
         None

src/libstd/sys/windows/thread_local.rs

@@ -69,9 +69,8 @@ static mut DTORS: *mut Vec<(Key, Dtor)> = ptr::null_mut();
 pub unsafe fn create(dtor: Option<Dtor>) -> Key {
     let key = c::TlsAlloc();
     assert!(key != c::TLS_OUT_OF_INDEXES);
-    match dtor {
-        Some(f) => register_dtor(key, f),
-        None => {}
+    if let Some(f) = dtor {
+        register_dtor(key, f);
     }
     return key;
 }