Auto merge of #100640 - reitermarkus:socket-display-buffer, r=thomcc

Use `DisplayBuffer` for socket addresses.

Continuation of https://github.com/rust-lang/rust/pull/100625 for socket addresses.

Renames `net::addr` to `net::addr::socket`, `net::ip` to `net::addr::ip` and `net::ip::display_buffer::IpDisplayBuffer` to `net::addr::display_buffer::DisplayBuffer`.

9 files changed, 167 insertions, 76 deletions

diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 416c42e3d51..81b0ebfb42c 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -214,6 +214,7 @@ symbols! {
         IntoIterator,
         IoRead,
         IoWrite,
+        IpAddr,
         IrTyKind,
         Is,
         ItemContext,
diff --git a/library/std/src/net/ip/display_buffer.rs b/library/std/src/net/display_buffer.rs
index bd852d5da8e..7aadf06e92f 100644
--- a/library/std/src/net/ip/display_buffer.rs
+++ b/library/std/src/net/display_buffer.rs
@@ -3,12 +3,12 @@ use crate::mem::MaybeUninit;
 use crate::str;
 
 /// Used for slow path in `Display` implementations when alignment is required.
-pub struct IpDisplayBuffer<const SIZE: usize> {
+pub struct DisplayBuffer<const SIZE: usize> {
     buf: [MaybeUninit<u8>; SIZE],
     len: usize,
 }
 
-impl<const SIZE: usize> IpDisplayBuffer<SIZE> {
+impl<const SIZE: usize> DisplayBuffer<SIZE> {
     #[inline]
     pub const fn new() -> Self {
         Self { buf: MaybeUninit::uninit_array(), len: 0 }
@@ -25,7 +25,7 @@ impl<const SIZE: usize> IpDisplayBuffer<SIZE> {
     }
 }
 
-impl<const SIZE: usize> fmt::Write for IpDisplayBuffer<SIZE> {
+impl<const SIZE: usize> fmt::Write for DisplayBuffer<SIZE> {
     fn write_str(&mut self, s: &str) -> fmt::Result {
         let bytes = s.as_bytes();
 
diff --git a/library/std/src/net/ip.rs b/library/std/src/net/ip_addr.rs
index 6004810655e..4f14fc28038 100644
--- a/library/std/src/net/ip.rs
+++ b/library/std/src/net/ip_addr.rs
@@ -8,8 +8,7 @@ use crate::mem::transmute;
 use crate::sys::net::netc as c;
 use crate::sys_common::{FromInner, IntoInner};
 
-mod display_buffer;
-use display_buffer::IpDisplayBuffer;
+use super::display_buffer::DisplayBuffer;
 
 /// An IP address, either IPv4 or IPv6.
 ///
@@ -30,6 +29,7 @@ use display_buffer::IpDisplayBuffer;
 /// assert_eq!(localhost_v4.is_ipv6(), false);
 /// assert_eq!(localhost_v4.is_ipv4(), true);
 /// ```
+#[cfg_attr(not(test), rustc_diagnostic_item = "IpAddr")]
 #[stable(feature = "ip_addr", since = "1.7.0")]
 #[derive(Copy, Clone, Eq, PartialEq, Hash, PartialOrd, Ord)]
 pub enum IpAddr {
@@ -73,6 +73,7 @@ pub enum IpAddr {
 /// assert!("0xcb.0x0.0x71.0x00".parse::<Ipv4Addr>().is_err()); // all octets are in hex
 /// ```
 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(not(test), rustc_diagnostic_item = "Ipv4Addr")]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Ipv4Addr {
     octets: [u8; 4],
@@ -155,6 +156,7 @@ pub struct Ipv4Addr {
 /// assert_eq!(localhost.is_loopback(), true);
 /// ```
 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(not(test), rustc_diagnostic_item = "Ipv6Addr")]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Ipv6Addr {
     octets: [u8; 16],
@@ -997,7 +999,7 @@ impl fmt::Display for Ipv4Addr {
         } else {
             const LONGEST_IPV4_ADDR: &str = "255.255.255.255";
 
-            let mut buf = IpDisplayBuffer::<{ LONGEST_IPV4_ADDR.len() }>::new();
+            let mut buf = DisplayBuffer::<{ 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();
 
@@ -1844,7 +1846,7 @@ impl fmt::Display for Ipv6Addr {
         } else {
             const LONGEST_IPV6_ADDR: &str = "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff";
 
-            let mut buf = IpDisplayBuffer::<{ LONGEST_IPV6_ADDR.len() }>::new();
+            let mut buf = DisplayBuffer::<{ LONGEST_IPV6_ADDR.len() }>::new();
             // Buffer is long enough for the longest possible IPv6 address, so this should never fail.
             write!(buf, "{}", self).unwrap();
 
diff --git a/library/std/src/net/ip/tests.rs b/library/std/src/net/ip_addr/tests.rs
index 7c3430b2b21..7c3430b2b21 100644
--- a/library/std/src/net/ip/tests.rs
+++ b/library/std/src/net/ip_addr/tests.rs
diff --git a/library/std/src/net/mod.rs b/library/std/src/net/mod.rs
index 6f9743f3a0e..01e3db9de51 100644
--- a/library/std/src/net/mod.rs
+++ b/library/std/src/net/mod.rs
@@ -24,11 +24,11 @@
 use crate::io::{self, ErrorKind};
 
 #[stable(feature = "rust1", since = "1.0.0")]
-pub use self::addr::{SocketAddr, SocketAddrV4, SocketAddrV6, ToSocketAddrs};
-#[stable(feature = "rust1", since = "1.0.0")]
-pub use self::ip::{IpAddr, Ipv4Addr, Ipv6Addr, Ipv6MulticastScope};
+pub use self::ip_addr::{IpAddr, Ipv4Addr, Ipv6Addr, Ipv6MulticastScope};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::parser::AddrParseError;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::socket_addr::{SocketAddr, SocketAddrV4, SocketAddrV6, ToSocketAddrs};
 #[unstable(feature = "tcplistener_into_incoming", issue = "88339")]
 pub use self::tcp::IntoIncoming;
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -36,9 +36,10 @@ pub use self::tcp::{Incoming, TcpListener, TcpStream};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::udp::UdpSocket;
 
-mod addr;
-mod ip;
+mod display_buffer;
+mod ip_addr;
 mod parser;
+mod socket_addr;
 mod tcp;
 #[cfg(test)]
 pub(crate) mod test;
diff --git a/library/std/src/net/addr.rs b/library/std/src/net/socket_addr.rs
index 53fee952a7a..33b0dfa03e0 100644
--- a/library/std/src/net/addr.rs
+++ b/library/std/src/net/socket_addr.rs
@@ -2,9 +2,9 @@
 mod tests;
 
 use crate::cmp::Ordering;
-use crate::fmt;
+use crate::fmt::{self, Write};
 use crate::hash;
-use crate::io::{self, Write};
+use crate::io;
 use crate::iter;
 use crate::mem;
 use crate::net::{IpAddr, Ipv4Addr, Ipv6Addr};
@@ -15,6 +15,8 @@ use crate::sys_common::net::LookupHost;
 use crate::sys_common::{FromInner, IntoInner};
 use crate::vec;
 
+use super::display_buffer::DisplayBuffer;
+
 /// An internet socket address, either IPv4 or IPv6.
 ///
 /// Internet socket addresses consist of an [IP address], a 16-bit port number, as well
@@ -616,25 +618,18 @@ impl fmt::Debug for SocketAddr {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Display for SocketAddrV4 {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        // Fast path: if there's no alignment stuff, write to the output buffer
-        // directly
+        // If there are no alignment requirements, write the socket address directly to `f`.
+        // Otherwise, write it to a local buffer and then use `f.pad`.
         if f.precision().is_none() && f.width().is_none() {
             write!(f, "{}:{}", self.ip(), self.port())
         } else {
-            const IPV4_SOCKET_BUF_LEN: usize = (3 * 4)  // the segments
-                + 3  // the separators
-                + 1 + 5; // the port
-            let mut buf = [0; IPV4_SOCKET_BUF_LEN];
-            let mut buf_slice = &mut buf[..];
-
-            // Unwrap is fine because writing to a sufficiently-sized
-            // buffer is infallible
-            write!(buf_slice, "{}:{}", self.ip(), self.port()).unwrap();
-            let len = IPV4_SOCKET_BUF_LEN - buf_slice.len();
-
-            // This unsafe is OK because we know what is being written to the buffer
-            let buf = unsafe { crate::str::from_utf8_unchecked(&buf[..len]) };
-            f.pad(buf)
+            const LONGEST_IPV4_SOCKET_ADDR: &str = "255.255.255.255:65536";
+
+            let mut buf = DisplayBuffer::<{ LONGEST_IPV4_SOCKET_ADDR.len() }>::new();
+            // Buffer is long enough for the longest possible IPv4 socket address, so this should never fail.
+            write!(buf, "{}:{}", self.ip(), self.port()).unwrap();
+
+            f.pad(buf.as_str())
         }
     }
 }
@@ -649,35 +644,26 @@ impl fmt::Debug for SocketAddrV4 {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Display for SocketAddrV6 {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        // Fast path: if there's no alignment stuff, write to the output
-        // buffer directly
+        // If there are no alignment requirements, write the socket address directly to `f`.
+        // Otherwise, write it to a local buffer and then use `f.pad`.
         if f.precision().is_none() && f.width().is_none() {
             match self.scope_id() {
                 0 => write!(f, "[{}]:{}", self.ip(), self.port()),
                 scope_id => write!(f, "[{}%{}]:{}", self.ip(), scope_id, self.port()),
             }
         } else {
-            const IPV6_SOCKET_BUF_LEN: usize = (4 * 8)  // The address
-            + 7  // The colon separators
-            + 2  // The brackets
-            + 1 + 10 // The scope id
-            + 1 + 5; // The port
-
-            let mut buf = [0; IPV6_SOCKET_BUF_LEN];
-            let mut buf_slice = &mut buf[..];
+            const LONGEST_IPV6_SOCKET_ADDR: &str =
+                "[ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff%4294967296]:65536";
 
+            let mut buf = DisplayBuffer::<{ LONGEST_IPV6_SOCKET_ADDR.len() }>::new();
             match self.scope_id() {
-                0 => write!(buf_slice, "[{}]:{}", self.ip(), self.port()),
-                scope_id => write!(buf_slice, "[{}%{}]:{}", self.ip(), scope_id, self.port()),
+                0 => write!(buf, "[{}]:{}", self.ip(), self.port()),
+                scope_id => write!(buf, "[{}%{}]:{}", self.ip(), scope_id, self.port()),
             }
-            // Unwrap is fine because writing to a sufficiently-sized
-            // buffer is infallible
+            // Buffer is long enough for the longest possible IPv6 socket address, so this should never fail.
             .unwrap();
-            let len = IPV6_SOCKET_BUF_LEN - buf_slice.len();
 
-            // This unsafe is OK because we know what is being written to the buffer
-            let buf = unsafe { crate::str::from_utf8_unchecked(&buf[..len]) };
-            f.pad(buf)
+            f.pad(buf.as_str())
         }
     }
 }
diff --git a/library/std/src/net/addr/tests.rs b/library/std/src/net/socket_addr/tests.rs
index 585a17451a0..15211f81981 100644
--- a/library/std/src/net/addr/tests.rs
+++ b/library/std/src/net/socket_addr/tests.rs
@@ -52,6 +52,75 @@ fn to_socket_addr_string() {
 }
 
 #[test]
+fn ipv4_socket_addr_to_string() {
+    // Shortest possible IPv4 length.
+    assert_eq!(SocketAddrV4::new(Ipv4Addr::new(0, 0, 0, 0), 0).to_string(), "0.0.0.0:0");
+
+    // Longest possible IPv4 length.
+    assert_eq!(
+        SocketAddrV4::new(Ipv4Addr::new(255, 255, 255, 255), u16::MAX).to_string(),
+        "255.255.255.255:65535"
+    );
+
+    // Test padding.
+    assert_eq!(
+        &format!("{:16}", SocketAddrV4::new(Ipv4Addr::new(1, 1, 1, 1), 53)),
+        "1.1.1.1:53      "
+    );
+    assert_eq!(
+        &format!("{:>16}", SocketAddrV4::new(Ipv4Addr::new(1, 1, 1, 1), 53)),
+        "      1.1.1.1:53"
+    );
+}
+
+#[test]
+fn ipv6_socket_addr_to_string() {
+    // IPv4-mapped address.
+    assert_eq!(
+        SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc000, 0x280), 8080, 0, 0)
+            .to_string(),
+        "[::ffff:192.0.2.128]:8080"
+    );
+
+    // IPv4-compatible address.
+    assert_eq!(
+        SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0xc000, 0x280), 8080, 0, 0).to_string(),
+        "[::192.0.2.128]:8080"
+    );
+
+    // IPv6 address with no zero segments.
+    assert_eq!(
+        SocketAddrV6::new(Ipv6Addr::new(8, 9, 10, 11, 12, 13, 14, 15), 80, 0, 0).to_string(),
+        "[8:9:a:b:c:d:e:f]:80"
+    );
+
+    // Shortest possible IPv6 length.
+    assert_eq!(SocketAddrV6::new(Ipv6Addr::UNSPECIFIED, 0, 0, 0).to_string(), "[::]:0");
+
+    // Longest possible IPv6 length.
+    assert_eq!(
+        SocketAddrV6::new(
+            Ipv6Addr::new(0x1111, 0x2222, 0x3333, 0x4444, 0x5555, 0x6666, 0x7777, 0x8888),
+            u16::MAX,
+            u32::MAX,
+            u32::MAX,
+        )
+        .to_string(),
+        "[1111:2222:3333:4444:5555:6666:7777:8888%4294967295]:65535"
+    );
+
+    // Test padding.
+    assert_eq!(
+        &format!("{:22}", SocketAddrV6::new(Ipv6Addr::new(1, 2, 3, 4, 5, 6, 7, 8), 9, 0, 0)),
+        "[1:2:3:4:5:6:7:8]:9   "
+    );
+    assert_eq!(
+        &format!("{:>22}", SocketAddrV6::new(Ipv6Addr::new(1, 2, 3, 4, 5, 6, 7, 8), 9, 0, 0)),
+        "   [1:2:3:4:5:6:7:8]:9"
+    );
+}
+
+#[test]
 fn bind_udp_socket_bad() {
     // rust-lang/rust#53957: This is a regression test for a parsing problem
     // discovered as part of issue rust-lang/rust#23076, where we were
diff --git a/src/tools/clippy/clippy_lints/src/matches/redundant_pattern_match.rs b/src/tools/clippy/clippy_lints/src/matches/redundant_pattern_match.rs
index f7443471e31..c89784065b8 100644
--- a/src/tools/clippy/clippy_lints/src/matches/redundant_pattern_match.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/redundant_pattern_match.rs
@@ -2,17 +2,17 @@ use super::REDUNDANT_PATTERN_MATCHING;
 use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::source::snippet;
 use clippy_utils::sugg::Sugg;
-use clippy_utils::ty::needs_ordered_drop;
+use clippy_utils::ty::{is_type_diagnostic_item, needs_ordered_drop};
 use clippy_utils::visitors::any_temporaries_need_ordered_drop;
-use clippy_utils::{higher, is_lang_ctor, is_trait_method, match_def_path, paths};
+use clippy_utils::{higher, is_lang_ctor, is_trait_method};
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;
-use rustc_hir::LangItem::{OptionNone, PollPending};
+use rustc_hir::LangItem::{self, OptionSome, OptionNone, PollPending, PollReady, ResultOk, ResultErr};
 use rustc_hir::{Arm, Expr, ExprKind, Node, Pat, PatKind, QPath, UnOp};
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, subst::GenericArgKind, DefIdTree, Ty};
-use rustc_span::sym;
+use rustc_span::{sym, Symbol};
 
 pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
     if let Some(higher::WhileLet { let_pat, let_expr, .. }) = higher::WhileLet::hir(expr) {
@@ -75,9 +75,9 @@ fn find_sugg_for_if_let<'tcx>(
                     ("is_some()", op_ty)
                 } else if Some(id) == lang_items.poll_ready_variant() {
                     ("is_ready()", op_ty)
-                } else if match_def_path(cx, id, &paths::IPADDR_V4) {
+                } else if is_pat_variant(cx, check_pat, qpath, Item::Diag(sym::IpAddr, sym!(V4))) {
                     ("is_ipv4()", op_ty)
-                } else if match_def_path(cx, id, &paths::IPADDR_V6) {
+                } else if is_pat_variant(cx, check_pat, qpath, Item::Diag(sym::IpAddr, sym!(V6))) {
                     ("is_ipv6()", op_ty)
                 } else {
                     return;
@@ -187,8 +187,8 @@ pub(super) fn check_match<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, op
                         arms,
                         path_left,
                         path_right,
-                        &paths::RESULT_OK,
-                        &paths::RESULT_ERR,
+                        Item::Lang(ResultOk),
+                        Item::Lang(ResultErr),
                         "is_ok()",
                         "is_err()",
                     )
@@ -198,8 +198,8 @@ pub(super) fn check_match<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, op
                             arms,
                             path_left,
                             path_right,
-                            &paths::IPADDR_V4,
-                            &paths::IPADDR_V6,
+                            Item::Diag(sym::IpAddr, sym!(V4)),
+                            Item::Diag(sym::IpAddr, sym!(V6)),
                             "is_ipv4()",
                             "is_ipv6()",
                         )
@@ -213,13 +213,14 @@ pub(super) fn check_match<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, op
                 if patterns.len() == 1 =>
             {
                 if let PatKind::Wild = patterns[0].kind {
+
                     find_good_method_for_match(
                         cx,
                         arms,
                         path_left,
                         path_right,
-                        &paths::OPTION_SOME,
-                        &paths::OPTION_NONE,
+                        Item::Lang(OptionSome),
+                        Item::Lang(OptionNone),
                         "is_some()",
                         "is_none()",
                     )
@@ -229,8 +230,8 @@ pub(super) fn check_match<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, op
                             arms,
                             path_left,
                             path_right,
-                            &paths::POLL_READY,
-                            &paths::POLL_PENDING,
+                            Item::Lang(PollReady),
+                            Item::Lang(PollPending),
                             "is_ready()",
                             "is_pending()",
                         )
@@ -266,28 +267,61 @@ pub(super) fn check_match<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, op
     }
 }
 
+#[derive(Clone, Copy)]
+enum Item {
+  Lang(LangItem),
+  Diag(Symbol, Symbol),
+}
+
+fn is_pat_variant(cx: &LateContext<'_>, pat: &Pat<'_>, path: &QPath<'_>, expected_item: Item) -> bool {
+    let Some(id) = cx.typeck_results().qpath_res(path, pat.hir_id).opt_def_id() else { return false };
+
+    match expected_item {
+        Item::Lang(expected_lang_item) => {
+            let expected_id = cx.tcx.lang_items().require(expected_lang_item).unwrap();
+            cx.tcx.parent(id) == expected_id
+        },
+        Item::Diag(expected_ty, expected_variant) => {
+            let ty = cx.typeck_results().pat_ty(pat);
+
+            if is_type_diagnostic_item(cx, ty, expected_ty) {
+                let variant = ty.ty_adt_def()
+                    .expect("struct pattern type is not an ADT")
+                    .variant_of_res(cx.qpath_res(path, pat.hir_id));
+
+                return variant.name == expected_variant
+            }
+
+            false
+        }
+    }
+}
+
 #[expect(clippy::too_many_arguments)]
 fn find_good_method_for_match<'a>(
     cx: &LateContext<'_>,
     arms: &[Arm<'_>],
     path_left: &QPath<'_>,
     path_right: &QPath<'_>,
-    expected_left: &[&str],
-    expected_right: &[&str],
+    expected_item_left: Item,
+    expected_item_right: Item,
     should_be_left: &'a str,
     should_be_right: &'a str,
 ) -> Option<&'a str> {
-    let left_id = cx
-        .typeck_results()
-        .qpath_res(path_left, arms[0].pat.hir_id)
-        .opt_def_id()?;
-    let right_id = cx
-        .typeck_results()
-        .qpath_res(path_right, arms[1].pat.hir_id)
-        .opt_def_id()?;
-    let body_node_pair = if match_def_path(cx, left_id, expected_left) && match_def_path(cx, right_id, expected_right) {
+    let pat_left = arms[0].pat;
+    let pat_right = arms[1].pat;
+
+    let body_node_pair = if (
+        is_pat_variant(cx, pat_left, path_left, expected_item_left)
+    ) && (
+        is_pat_variant(cx, pat_right, path_right, expected_item_right)
+    ) {
         (&arms[0].body.kind, &arms[1].body.kind)
-    } else if match_def_path(cx, right_id, expected_left) && match_def_path(cx, right_id, expected_right) {
+    } else if (
+        is_pat_variant(cx, pat_left, path_left, expected_item_right)
+    ) && (
+        is_pat_variant(cx, pat_right, path_right, expected_item_left)
+    ) {
         (&arms[1].body.kind, &arms[0].body.kind)
     } else {
         return None;
diff --git a/src/tools/clippy/clippy_utils/src/paths.rs b/src/tools/clippy/clippy_utils/src/paths.rs
index fb0d34e02ee..07170e2df12 100644
--- a/src/tools/clippy/clippy_utils/src/paths.rs
+++ b/src/tools/clippy/clippy_utils/src/paths.rs
@@ -66,8 +66,6 @@ pub const INDEX_MUT: [&str; 3] = ["core", "ops", "IndexMut"];
 pub const INSERT_STR: [&str; 4] = ["alloc", "string", "String", "insert_str"];
 pub const IO_READ: [&str; 3] = ["std", "io", "Read"];
 pub const IO_WRITE: [&str; 3] = ["std", "io", "Write"];
-pub const IPADDR_V4: [&str; 5] = ["std", "net", "ip", "IpAddr", "V4"];
-pub const IPADDR_V6: [&str; 5] = ["std", "net", "ip", "IpAddr", "V6"];
 pub const ITER_COUNT: [&str; 6] = ["core", "iter", "traits", "iterator", "Iterator", "count"];
 pub const ITER_EMPTY: [&str; 5] = ["core", "iter", "sources", "empty", "Empty"];
 pub const ITER_REPEAT: [&str; 5] = ["core", "iter", "sources", "repeat", "repeat"];