mark with SocketAddr::new, SocketAddrV4::new and SocketAddrV6::new rustc_const_unstable attribute

Author: Marco Conte

src/libstd/net/addr.rs

@@ -125,6 +125,7 @@ impl SocketAddr {
     /// assert_eq!(socket.port(), 8080);
     /// ```
     #[stable(feature = "ip_addr", since = "1.7.0")]
+    #[rustc_const_unstable(feature = "const_socket_new", issue = "67390")]
     pub const fn new(ip: IpAddr, port: u16) -> SocketAddr {
         match ip {
             IpAddr::V4(a) => SocketAddr::V4(SocketAddrV4::new(a, port)),
@@ -272,6 +273,7 @@ impl SocketAddrV4 {
     /// let socket = SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 8080);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_socket_new", issue = "67390")]
     pub const fn new(ip: Ipv4Addr, port: u16) -> SocketAddrV4 {
         SocketAddrV4 {
             inner: c::sockaddr_in {
@@ -364,6 +366,7 @@ impl SocketAddrV6 {
     /// let socket = SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1), 8080, 0, 0);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_socket_new", issue = "67390")]
     pub const fn new(ip: Ipv6Addr, port: u16, flowinfo: u32, scope_id: u32) -> SocketAddrV6 {
         SocketAddrV6 {
             inner: c::sockaddr_in6 {