Simplify IpDisplayBuffer API.

library/std/src/net/ip.rs

@@ -999,7 +999,9 @@ impl fmt::Display for Ipv4Addr {
         if fmt.precision().is_none() && fmt.width().is_none() {
             write!(fmt, "{}.{}.{}.{}", octets[0], octets[1], octets[2], octets[3])
         } else {
-            let mut buf = IpDisplayBuffer::new(b"255.255.255.255");
+            const LONGEST_IPV4_ADDR: &str = "255.255.255.255";
+
+            let mut buf = IpDisplayBuffer::<{ LONGEST_IPV4_ADDR.len() }>::new();
             // Buffer is long enough for the longest possible IPv4 address, so this should never fail.
             write!(buf, "{}.{}.{}.{}", octets[0], octets[1], octets[2], octets[3]).unwrap();
 
@@ -1778,7 +1780,9 @@ impl fmt::Display for Ipv6Addr {
                 }
             }
         } else {
-            let mut buf = IpDisplayBuffer::new(b"ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff");
+            const LONGEST_IPV6_ADDR: &str = "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff";
+
+            let mut buf = IpDisplayBuffer::<{ LONGEST_IPV6_ADDR.len() }>::new();
             // Buffer is long enough for the longest possible IPv6 address, so this should never fail.
             write!(buf, "{}", self).unwrap();
 

library/std/src/net/ip/display_buffer.rs

@@ -9,12 +9,12 @@ pub struct IpDisplayBuffer<const SIZE: usize> {
 }
 
 impl<const SIZE: usize> IpDisplayBuffer<SIZE> {
-    #[inline(always)]
-    pub const fn new(_ip: &[u8; SIZE]) -> Self {
-        Self { buf: MaybeUninit::uninit_array::<SIZE>(), len: 0 }
+    #[inline]
+    pub const fn new() -> Self {
+        Self { buf: MaybeUninit::uninit_array(), len: 0 }
     }
 
-    #[inline(always)]
+    #[inline]
     pub fn as_str(&self) -> &str {
         // SAFETY: `buf` is only written to by the `fmt::Write::write_str` implementation
         // which writes a valid UTF-8 string to `buf` and correctly sets `len`.