diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index fa2802a891fbd..7c79cba2273d4 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -1929,11 +1929,17 @@ unsafe extern "C" {
         C: &Context,
         effects: MemoryEffects,
     ) -> &Attribute;
+    /// ## Safety
+    /// - Each of `LowerWords` and `UpperWords` must point to an array that is
+    ///   long enough to fully define an integer of size `NumBits`, i.e. each
+    ///   pointer must point to `NumBits.div_ceil(64)` elements or more.
+    /// - The implementation will make its own copy of the pointed-to `u64`
+    ///   values, so the pointers only need to outlive this function call.
     pub(crate) fn LLVMRustCreateRangeAttribute(
         C: &Context,
-        num_bits: c_uint,
-        lower_words: *const u64,
-        upper_words: *const u64,
+        NumBits: c_uint,
+        LowerWords: *const u64,
+        UpperWords: *const u64,
     ) -> &Attribute;
 
     // Operations on functions
diff --git a/compiler/rustc_codegen_llvm/src/llvm/mod.rs b/compiler/rustc_codegen_llvm/src/llvm/mod.rs
index 6adabe5312969..d6974e22c85c5 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/mod.rs
@@ -112,16 +112,26 @@ pub(crate) fn CreateAllocKindAttr(llcx: &Context, kind_arg: AllocKindFlags) -> &
 
 pub(crate) fn CreateRangeAttr(llcx: &Context, size: Size, range: WrappingRange) -> &Attribute {
     let lower = range.start;
+    // LLVM treats the upper bound as exclusive, but allows wrapping.
     let upper = range.end.wrapping_add(1);
-    let lower_words = [lower as u64, (lower >> 64) as u64];
-    let upper_words = [upper as u64, (upper >> 64) as u64];
+
+    // Pass each `u128` endpoint value as a `[u64; 2]` array, least-significant part first.
+    let as_u64_array = |x: u128| [x as u64, (x >> 64) as u64];
+    let lower_words: [u64; 2] = as_u64_array(lower);
+    let upper_words: [u64; 2] = as_u64_array(upper);
+
+    // To ensure that LLVM doesn't try to read beyond the `[u64; 2]` arrays,
+    // we must explicitly check that `size_bits` does not exceed 128.
+    let size_bits = size.bits();
+    assert!(size_bits <= 128);
+    // More robust assertions that are redundant with `size_bits <= 128` and
+    // should be optimized away.
+    assert!(size_bits.div_ceil(64) <= u64::try_from(lower_words.len()).unwrap());
+    assert!(size_bits.div_ceil(64) <= u64::try_from(upper_words.len()).unwrap());
+    let size_bits = c_uint::try_from(size_bits).unwrap();
+
     unsafe {
-        LLVMRustCreateRangeAttribute(
-            llcx,
-            size.bits().try_into().unwrap(),
-            lower_words.as_ptr(),
-            upper_words.as_ptr(),
-        )
+        LLVMRustCreateRangeAttribute(llcx, size_bits, lower_words.as_ptr(), upper_words.as_ptr())
     }
 }
 
diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index d5025bb405cc5..d927ffd78c298 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -279,7 +279,7 @@ pub(crate) fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> Option<LLVMFea
         }
         ("loongarch32" | "loongarch64", "32s") if get_version().0 < 21 => None,
         // Filter out features that are not supported by the current LLVM version
-        ("riscv32" | "riscv64", "zacas") if get_version().0 < 20 => None,
+        ("riscv32" | "riscv64", "zacas" | "rva23u64" | "supm") if get_version().0 < 20 => None,
         (
             "s390x",
             "message-security-assist-extension12"
diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
index e699e4b9c13f8..cce40da354d34 100644
--- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -488,6 +488,9 @@ extern "C" LLVMAttributeRef
 LLVMRustCreateRangeAttribute(LLVMContextRef C, unsigned NumBits,
                              const uint64_t LowerWords[],
                              const uint64_t UpperWords[]) {
+  // FIXME(Zalathar): There appears to be no stable guarantee that C++
+  // `AttrKind` values correspond directly to the `unsigned KindID` values
+  // accepted by LLVM-C API functions, though in practice they currently do.
   return LLVMCreateConstantRangeAttribute(C, Attribute::Range, NumBits,
                                           LowerWords, UpperWords);
 }
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index a67795e3e9312..c53d92bee9d29 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -1954,6 +1954,7 @@ supported_targets! {
     ("armv7-unknown-linux-musleabihf", armv7_unknown_linux_musleabihf),
     ("aarch64-unknown-linux-gnu", aarch64_unknown_linux_gnu),
     ("aarch64-unknown-linux-musl", aarch64_unknown_linux_musl),
+    ("aarch64_be-unknown-linux-musl", aarch64_be_unknown_linux_musl),
     ("x86_64-unknown-linux-musl", x86_64_unknown_linux_musl),
     ("i686-unknown-linux-musl", i686_unknown_linux_musl),
     ("i586-unknown-linux-musl", i586_unknown_linux_musl),
@@ -2149,6 +2150,7 @@ supported_targets! {
     ("riscv64gc-unknown-none-elf", riscv64gc_unknown_none_elf),
     ("riscv64gc-unknown-linux-gnu", riscv64gc_unknown_linux_gnu),
     ("riscv64gc-unknown-linux-musl", riscv64gc_unknown_linux_musl),
+    ("riscv64a23-unknown-linux-gnu", riscv64a23_unknown_linux_gnu),
 
     ("sparc-unknown-none-elf", sparc_unknown_none_elf),
 
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_be_unknown_linux_musl.rs b/compiler/rustc_target/src/spec/targets/aarch64_be_unknown_linux_musl.rs
new file mode 100644
index 0000000000000..be5ac4a843baf
--- /dev/null
+++ b/compiler/rustc_target/src/spec/targets/aarch64_be_unknown_linux_musl.rs
@@ -0,0 +1,40 @@
+use rustc_abi::Endian;
+
+use crate::spec::{
+    FramePointer, SanitizerSet, StackProbeType, Target, TargetMetadata, TargetOptions, base,
+};
+
+pub(crate) fn target() -> Target {
+    let mut base = base::linux_musl::opts();
+    base.max_atomic_width = Some(128);
+    base.supports_xray = true;
+    base.features = "+v8a,+outline-atomics".into();
+    base.stack_probes = StackProbeType::Inline;
+    base.supported_sanitizers = SanitizerSet::ADDRESS
+        | SanitizerSet::CFI
+        | SanitizerSet::LEAK
+        | SanitizerSet::MEMORY
+        | SanitizerSet::THREAD;
+
+    Target {
+        llvm_target: "aarch64_be-unknown-linux-musl".into(),
+        metadata: TargetMetadata {
+            description: Some("ARM64 Linux (big-endian) with musl-libc 1.2.5".into()),
+            tier: Some(3),
+            host_tools: Some(false),
+            std: Some(true),
+        },
+        pointer_width: 64,
+        data_layout: "E-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        arch: "aarch64".into(),
+        options: TargetOptions {
+            // the AAPCS64 expects use of non-leaf frame pointers per
+            // https://github.com/ARM-software/abi-aa/blob/4492d1570eb70c8fd146623e0db65b2d241f12e7/aapcs64/aapcs64.rst#the-frame-pointer
+            // and we tend to encounter interesting bugs in AArch64 unwinding code if we do not
+            frame_pointer: FramePointer::NonLeaf,
+            mcount: "\u{1}_mcount".into(),
+            endian: Endian::Big,
+            ..base
+        },
+    }
+}
diff --git a/compiler/rustc_target/src/spec/targets/riscv64a23_unknown_linux_gnu.rs b/compiler/rustc_target/src/spec/targets/riscv64a23_unknown_linux_gnu.rs
new file mode 100644
index 0000000000000..60f2e7da042cc
--- /dev/null
+++ b/compiler/rustc_target/src/spec/targets/riscv64a23_unknown_linux_gnu.rs
@@ -0,0 +1,27 @@
+use std::borrow::Cow;
+
+use crate::spec::{CodeModel, SplitDebuginfo, Target, TargetMetadata, TargetOptions, base};
+
+pub(crate) fn target() -> Target {
+    Target {
+        llvm_target: "riscv64-unknown-linux-gnu".into(),
+        metadata: TargetMetadata {
+            description: Some("RISC-V Linux (kernel 6.8.0, glibc 2.39)".into()),
+            tier: Some(3),
+            host_tools: Some(true),
+            std: Some(true),
+        },
+        pointer_width: 64,
+        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128".into(),
+        arch: "riscv64".into(),
+        options: TargetOptions {
+            code_model: Some(CodeModel::Medium),
+            cpu: "generic-rv64".into(),
+            features: "+rva23u64".into(),
+            llvm_abiname: "lp64d".into(),
+            max_atomic_width: Some(64),
+            supported_split_debuginfo: Cow::Borrowed(&[SplitDebuginfo::Off]),
+            ..base::linux_gnu::opts()
+        },
+    }
+}
diff --git a/compiler/rustc_target/src/target_features.rs b/compiler/rustc_target/src/target_features.rs
index e45300b59cc73..4c1b8c99426b6 100644
--- a/compiler/rustc_target/src/target_features.rs
+++ b/compiler/rustc_target/src/target_features.rs
@@ -601,6 +601,49 @@ static RISCV_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     ),
     ("m", Stable, &[]),
     ("relax", Unstable(sym::riscv_target_feature), &[]),
+    (
+        "rva23u64",
+        Unstable(sym::riscv_target_feature),
+        &[
+            "m",
+            "a",
+            "f",
+            "d",
+            "c",
+            "b",
+            "v",
+            "zicsr",
+            "zicntr",
+            "zihpm",
+            "ziccif",
+            "ziccrse",
+            "ziccamoa",
+            "zicclsm",
+            "zic64b",
+            "za64rs",
+            "zihintpause",
+            "zba",
+            "zbb",
+            "zbs",
+            "zicbom",
+            "zicbop",
+            "zicboz",
+            "zfhmin",
+            "zkt",
+            "zvfhmin",
+            "zvbb",
+            "zvkt",
+            "zihintntl",
+            "zicond",
+            "zimop",
+            "zcmop",
+            "zcb",
+            "zfa",
+            "zawrs",
+            "supm",
+        ],
+    ),
+    ("supm", Unstable(sym::riscv_target_feature), &[]),
     ("unaligned-scalar-mem", Unstable(sym::riscv_target_feature), &[]),
     ("unaligned-vector-mem", Unstable(sym::riscv_target_feature), &[]),
     ("v", Unstable(sym::riscv_target_feature), &["zvl128b", "zve64d"]),
diff --git a/compiler/rustc_thread_pool/src/lib.rs b/compiler/rustc_thread_pool/src/lib.rs
index 34252d919e38e..7ce7fbc27eabe 100644
--- a/compiler/rustc_thread_pool/src/lib.rs
+++ b/compiler/rustc_thread_pool/src/lib.rs
@@ -787,18 +787,7 @@ impl ThreadPoolBuildError {
     }
 }
 
-const GLOBAL_POOL_ALREADY_INITIALIZED: &str =
-    "The global thread pool has already been initialized.";
-
 impl Error for ThreadPoolBuildError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        match self.kind {
-            ErrorKind::GlobalPoolAlreadyInitialized => GLOBAL_POOL_ALREADY_INITIALIZED,
-            ErrorKind::IOError(ref e) => e.description(),
-        }
-    }
-
     fn source(&self) -> Option<&(dyn Error + 'static)> {
         match &self.kind {
             ErrorKind::GlobalPoolAlreadyInitialized => None,
@@ -810,7 +799,9 @@ impl Error for ThreadPoolBuildError {
 impl fmt::Display for ThreadPoolBuildError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match &self.kind {
-            ErrorKind::GlobalPoolAlreadyInitialized => GLOBAL_POOL_ALREADY_INITIALIZED.fmt(f),
+            ErrorKind::GlobalPoolAlreadyInitialized => {
+                "The global thread pool has already been initialized.".fmt(f)
+            }
             ErrorKind::IOError(e) => e.fmt(f),
         }
     }
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
index e31ff8b872981..aa153d3607bf5 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
@@ -820,16 +820,20 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         if matches!(obligation.cause.code(), ObligationCauseCode::FunctionArg { .. })
             && obligation.cause.span.can_be_used_for_suggestions()
         {
+            let (span, sugg) = if let Some(snippet) =
+                self.tcx.sess.source_map().span_to_snippet(obligation.cause.span).ok()
+                && snippet.starts_with("|")
+            {
+                (obligation.cause.span, format!("({snippet})({args})"))
+            } else {
+                (obligation.cause.span.shrink_to_hi(), format!("({args})"))
+            };
+
             // When the obligation error has been ensured to have been caused by
             // an argument, the `obligation.cause.span` points at the expression
             // of the argument, so we can provide a suggestion. Otherwise, we give
             // a more general note.
-            err.span_suggestion_verbose(
-                obligation.cause.span.shrink_to_hi(),
-                msg,
-                format!("({args})"),
-                Applicability::HasPlaceholders,
-            );
+            err.span_suggestion_verbose(span, msg, sugg, Applicability::HasPlaceholders);
         } else if let DefIdOrName::DefId(def_id) = def_id_or_name {
             let name = match self.tcx.hir_get_if_local(def_id) {
                 Some(hir::Node::Expr(hir::Expr {
diff --git a/library/alloc/src/boxed.rs b/library/alloc/src/boxed.rs
index fa12d379c8cae..98c9f6b51ab86 100644
--- a/library/alloc/src/boxed.rs
+++ b/library/alloc/src/boxed.rs
@@ -2128,11 +2128,6 @@ impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A> {
 
 #[stable(feature = "box_error", since = "1.8.0")]
 impl<E: Error> Error for Box<E> {
-    #[allow(deprecated, deprecated_in_future)]
-    fn description(&self) -> &str {
-        Error::description(&**self)
-    }
-
     #[allow(deprecated)]
     fn cause(&self) -> Option<&dyn Error> {
         Error::cause(&**self)
diff --git a/library/alloc/src/boxed/convert.rs b/library/alloc/src/boxed/convert.rs
index 8062658020239..45c46fb526365 100644
--- a/library/alloc/src/boxed/convert.rs
+++ b/library/alloc/src/boxed/convert.rs
@@ -608,12 +608,7 @@ impl<'a> From<String> for Box<dyn Error + Send + Sync + 'a> {
     fn from(err: String) -> Box<dyn Error + Send + Sync + 'a> {
         struct StringError(String);
 
-        impl Error for StringError {
-            #[allow(deprecated)]
-            fn description(&self) -> &str {
-                &self.0
-            }
-        }
+        impl Error for StringError {}
 
         impl fmt::Display for StringError {
             fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
diff --git a/library/alloc/src/collections/btree/map/entry.rs b/library/alloc/src/collections/btree/map/entry.rs
index ea8fa363c3805..ec9b774c30877 100644
--- a/library/alloc/src/collections/btree/map/entry.rs
+++ b/library/alloc/src/collections/btree/map/entry.rs
@@ -136,10 +136,6 @@ impl<'a, K: Debug + Ord, V: Debug, A: Allocator + Clone> fmt::Display
 impl<'a, K: core::fmt::Debug + Ord, V: core::fmt::Debug> core::error::Error
     for crate::collections::btree_map::OccupiedError<'a, K, V>
 {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "key already exists"
-    }
 }
 
 impl<'a, K: Ord, V, A: Allocator + Clone> Entry<'a, K, V, A> {
diff --git a/library/alloc/src/ffi/c_str.rs b/library/alloc/src/ffi/c_str.rs
index fe6c89a30949d..b0c8c4b1ca4a7 100644
--- a/library/alloc/src/ffi/c_str.rs
+++ b/library/alloc/src/ffi/c_str.rs
@@ -1061,17 +1061,10 @@ impl IntoStringError {
     }
 }
 
-impl IntoStringError {
-    fn description(&self) -> &str {
-        "C string contained non-utf8 bytes"
-    }
-}
-
 #[stable(feature = "cstring_into", since = "1.7.0")]
 impl fmt::Display for IntoStringError {
-    #[allow(deprecated, deprecated_in_future)]
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        self.description().fmt(f)
+        "C string contained non-utf8 bytes".fmt(f)
     }
 }
 
@@ -1291,23 +1284,13 @@ impl PartialEq<CString> for Cow<'_, CStr> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl core::error::Error for NulError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "nul byte found in data"
-    }
-}
+impl core::error::Error for NulError {}
 
 #[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")]
 impl core::error::Error for FromVecWithNulError {}
 
 #[stable(feature = "cstring_into", since = "1.7.0")]
 impl core::error::Error for IntoStringError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "C string contained non-utf8 bytes"
-    }
-
     fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
         Some(&self.error)
     }
diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs
index 9eacbf00e4233..11fd4346ff504 100644
--- a/library/alloc/src/string.rs
+++ b/library/alloc/src/string.rs
@@ -2285,20 +2285,10 @@ impl fmt::Display for FromUtf16Error {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl Error for FromUtf8Error {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "invalid utf-8"
-    }
-}
+impl Error for FromUtf8Error {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl Error for FromUtf16Error {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "invalid utf-16"
-    }
-}
+impl Error for FromUtf16Error {}
 
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs
index 29caa7bc5393c..a21b6880674c6 100644
--- a/library/alloc/src/sync.rs
+++ b/library/alloc/src/sync.rs
@@ -4113,11 +4113,6 @@ impl<T: ?Sized, A: Allocator> Drop for UniqueArcUninit<T, A> {
 
 #[stable(feature = "arc_error", since = "1.52.0")]
 impl<T: core::error::Error + ?Sized> core::error::Error for Arc<T> {
-    #[allow(deprecated, deprecated_in_future)]
-    fn description(&self) -> &str {
-        core::error::Error::description(&**self)
-    }
-
     #[allow(deprecated)]
     fn cause(&self) -> Option<&dyn core::error::Error> {
         core::error::Error::cause(&**self)
diff --git a/library/core/src/array/mod.rs b/library/core/src/array/mod.rs
index bb75ec74c8177..835ee57ce230b 100644
--- a/library/core/src/array/mod.rs
+++ b/library/core/src/array/mod.rs
@@ -184,18 +184,12 @@ pub struct TryFromSliceError(());
 impl fmt::Display for TryFromSliceError {
     #[inline]
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        #[allow(deprecated)]
-        self.description().fmt(f)
+        "could not convert slice to array".fmt(f)
     }
 }
 
 #[stable(feature = "try_from", since = "1.34.0")]
-impl Error for TryFromSliceError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "could not convert slice to array"
-    }
-}
+impl Error for TryFromSliceError {}
 
 #[stable(feature = "try_from_slice_error", since = "1.36.0")]
 #[rustc_const_unstable(feature = "const_try", issue = "74935")]
diff --git a/library/core/src/char/convert.rs b/library/core/src/char/convert.rs
index 23061cb663bc6..cf5a91bf8ddb5 100644
--- a/library/core/src/char/convert.rs
+++ b/library/core/src/char/convert.rs
@@ -193,21 +193,16 @@ enum CharErrorKind {
 }
 
 #[stable(feature = "char_from_str", since = "1.20.0")]
-impl Error for ParseCharError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        match self.kind {
-            CharErrorKind::EmptyString => "cannot parse char from empty string",
-            CharErrorKind::TooManyChars => "too many characters in string",
-        }
-    }
-}
+impl Error for ParseCharError {}
 
 #[stable(feature = "char_from_str", since = "1.20.0")]
 impl fmt::Display for ParseCharError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        #[allow(deprecated)]
-        self.description().fmt(f)
+        match self.kind {
+            CharErrorKind::EmptyString => "cannot parse char from empty string",
+            CharErrorKind::TooManyChars => "too many characters in string",
+        }
+        .fmt(f)
     }
 }
 
diff --git a/library/core/src/char/decode.rs b/library/core/src/char/decode.rs
index 23319fbe5ddc4..d7c5f45ae4ed7 100644
--- a/library/core/src/char/decode.rs
+++ b/library/core/src/char/decode.rs
@@ -126,9 +126,4 @@ impl fmt::Display for DecodeUtf16Error {
 }
 
 #[stable(feature = "decode_utf16", since = "1.9.0")]
-impl Error for DecodeUtf16Error {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "unpaired surrogate found"
-    }
-}
+impl Error for DecodeUtf16Error {}
diff --git a/library/core/src/convert/mod.rs b/library/core/src/convert/mod.rs
index 0c3034c3d4cf2..a0a7b7928d16c 100644
--- a/library/core/src/convert/mod.rs
+++ b/library/core/src/convert/mod.rs
@@ -958,11 +958,7 @@ impl fmt::Display for Infallible {
 }
 
 #[stable(feature = "str_parse_error2", since = "1.8.0")]
-impl Error for Infallible {
-    fn description(&self) -> &str {
-        match *self {}
-    }
-}
+impl Error for Infallible {}
 
 #[stable(feature = "convert_infallible", since = "1.34.0")]
 #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
diff --git a/library/core/src/error.rs b/library/core/src/error.rs
index 88e633c9eef3f..92b3c83d1bf34 100644
--- a/library/core/src/error.rs
+++ b/library/core/src/error.rs
@@ -1042,11 +1042,6 @@ impl<'a> crate::iter::FusedIterator for Source<'a> {}
 
 #[stable(feature = "error_by_ref", since = "1.51.0")]
 impl<'a, T: Error + ?Sized> Error for &'a T {
-    #[allow(deprecated, deprecated_in_future)]
-    fn description(&self) -> &str {
-        Error::description(&**self)
-    }
-
     #[allow(deprecated)]
     fn cause(&self) -> Option<&dyn Error> {
         Error::cause(&**self)
@@ -1062,36 +1057,16 @@ impl<'a, T: Error + ?Sized> Error for &'a T {
 }
 
 #[stable(feature = "fmt_error", since = "1.11.0")]
-impl Error for crate::fmt::Error {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "an error occurred when formatting an argument"
-    }
-}
+impl Error for crate::fmt::Error {}
 
 #[stable(feature = "try_borrow", since = "1.13.0")]
-impl Error for crate::cell::BorrowError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "already mutably borrowed"
-    }
-}
+impl Error for crate::cell::BorrowError {}
 
 #[stable(feature = "try_borrow", since = "1.13.0")]
-impl Error for crate::cell::BorrowMutError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "already borrowed"
-    }
-}
+impl Error for crate::cell::BorrowMutError {}
 
 #[stable(feature = "try_from", since = "1.34.0")]
-impl Error for crate::char::CharTryFromError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "converted integer out of range for `char`"
-    }
-}
+impl Error for crate::char::CharTryFromError {}
 
 #[stable(feature = "duration_checked_float", since = "1.66.0")]
 impl Error for crate::time::TryFromFloatSecsError {}
diff --git a/library/core/src/fmt/mod.rs b/library/core/src/fmt/mod.rs
index 8ac29e5b07638..b6de892530892 100644
--- a/library/core/src/fmt/mod.rs
+++ b/library/core/src/fmt/mod.rs
@@ -359,7 +359,7 @@ impl FormattingOptions {
     ///   always be printed.
     /// - `-`: Currently not used
     #[unstable(feature = "formatting_options", issue = "118117")]
-    pub fn sign(&mut self, sign: Option<Sign>) -> &mut Self {
+    pub const fn sign(&mut self, sign: Option<Sign>) -> &mut Self {
         let sign = match sign {
             None => 0,
             Some(Sign::Plus) => flags::SIGN_PLUS_FLAG,
@@ -372,7 +372,7 @@ impl FormattingOptions {
     ///
     /// This is used to indicate for integer formats that the padding to width should both be done with a 0 character as well as be sign-aware
     #[unstable(feature = "formatting_options", issue = "118117")]
-    pub fn sign_aware_zero_pad(&mut self, sign_aware_zero_pad: bool) -> &mut Self {
+    pub const fn sign_aware_zero_pad(&mut self, sign_aware_zero_pad: bool) -> &mut Self {
         if sign_aware_zero_pad {
             self.flags |= flags::SIGN_AWARE_ZERO_PAD_FLAG;
         } else {
@@ -389,7 +389,7 @@ impl FormattingOptions {
     /// - [`Octal`] - precedes the argument with a `0b`
     /// - [`Binary`] - precedes the argument with a `0o`
     #[unstable(feature = "formatting_options", issue = "118117")]
-    pub fn alternate(&mut self, alternate: bool) -> &mut Self {
+    pub const fn alternate(&mut self, alternate: bool) -> &mut Self {
         if alternate {
             self.flags |= flags::ALTERNATE_FLAG;
         } else {
@@ -404,7 +404,7 @@ impl FormattingOptions {
     /// being formatted is smaller than width some extra characters will be
     /// printed around it.
     #[unstable(feature = "formatting_options", issue = "118117")]
-    pub fn fill(&mut self, fill: char) -> &mut Self {
+    pub const fn fill(&mut self, fill: char) -> &mut Self {
         self.flags = self.flags & (u32::MAX << 21) | fill as u32;
         self
     }
@@ -413,7 +413,7 @@ impl FormattingOptions {
     /// The alignment specifies how the value being formatted should be
     /// positioned if it is smaller than the width of the formatter.
     #[unstable(feature = "formatting_options", issue = "118117")]
-    pub fn align(&mut self, align: Option<Alignment>) -> &mut Self {
+    pub const fn align(&mut self, align: Option<Alignment>) -> &mut Self {
         let align: u32 = match align {
             Some(Alignment::Left) => flags::ALIGN_LEFT,
             Some(Alignment::Right) => flags::ALIGN_RIGHT,
@@ -430,7 +430,7 @@ impl FormattingOptions {
     /// the padding specified by [`FormattingOptions::fill`]/[`FormattingOptions::align`]
     /// will be used to take up the required space.
     #[unstable(feature = "formatting_options", issue = "118117")]
-    pub fn width(&mut self, width: Option<u16>) -> &mut Self {
+    pub const fn width(&mut self, width: Option<u16>) -> &mut Self {
         if let Some(width) = width {
             self.flags |= flags::WIDTH_FLAG;
             self.width = width;
@@ -450,7 +450,7 @@ impl FormattingOptions {
     /// - For floating-point types, this indicates how many digits after the
     /// decimal point should be printed.
     #[unstable(feature = "formatting_options", issue = "118117")]
-    pub fn precision(&mut self, precision: Option<u16>) -> &mut Self {
+    pub const fn precision(&mut self, precision: Option<u16>) -> &mut Self {
         if let Some(precision) = precision {
             self.flags |= flags::PRECISION_FLAG;
             self.precision = precision;
@@ -463,7 +463,7 @@ impl FormattingOptions {
     /// Specifies whether the [`Debug`] trait should use lower-/upper-case
     /// hexadecimal or normal integers
     #[unstable(feature = "formatting_options", issue = "118117")]
-    pub fn debug_as_hex(&mut self, debug_as_hex: Option<DebugAsHex>) -> &mut Self {
+    pub const fn debug_as_hex(&mut self, debug_as_hex: Option<DebugAsHex>) -> &mut Self {
         let debug_as_hex = match debug_as_hex {
             None => 0,
             Some(DebugAsHex::Lower) => flags::DEBUG_LOWER_HEX_FLAG,
@@ -537,7 +537,7 @@ impl FormattingOptions {
     ///
     /// You may alternatively use [`Formatter::new()`].
     #[unstable(feature = "formatting_options", issue = "118117")]
-    pub fn create_formatter<'a>(self, write: &'a mut (dyn Write + 'a)) -> Formatter<'a> {
+    pub const fn create_formatter<'a>(self, write: &'a mut (dyn Write + 'a)) -> Formatter<'a> {
         Formatter { options: self, buf: write }
     }
 }
@@ -578,13 +578,13 @@ impl<'a> Formatter<'a> {
     ///
     /// You may alternatively use [`FormattingOptions::create_formatter()`].
     #[unstable(feature = "formatting_options", issue = "118117")]
-    pub fn new(write: &'a mut (dyn Write + 'a), options: FormattingOptions) -> Self {
+    pub const fn new(write: &'a mut (dyn Write + 'a), options: FormattingOptions) -> Self {
         Formatter { options, buf: write }
     }
 
     /// Creates a new formatter based on this one with given [`FormattingOptions`].
     #[unstable(feature = "formatting_options", issue = "118117")]
-    pub fn with_options<'b>(&'b mut self, options: FormattingOptions) -> Formatter<'b> {
+    pub const fn with_options<'b>(&'b mut self, options: FormattingOptions) -> Formatter<'b> {
         Formatter { options, buf: self.buf }
     }
 }
diff --git a/library/core/src/net/parser.rs b/library/core/src/net/parser.rs
index 73230f6ee5b03..3aab24a90d817 100644
--- a/library/core/src/net/parser.rs
+++ b/library/core/src/net/parser.rs
@@ -497,16 +497,7 @@ pub struct AddrParseError(AddrKind);
 
 #[stable(feature = "addr_parse_error_error", since = "1.4.0")]
 impl fmt::Display for AddrParseError {
-    #[allow(deprecated, deprecated_in_future)]
-    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt.write_str(self.description())
-    }
-}
-
-#[stable(feature = "addr_parse_error_error", since = "1.4.0")]
-impl Error for AddrParseError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.0 {
             AddrKind::Ip => "invalid IP address syntax",
             AddrKind::Ipv4 => "invalid IPv4 address syntax",
@@ -515,5 +506,9 @@ impl Error for AddrParseError {
             AddrKind::SocketV4 => "invalid IPv4 socket address syntax",
             AddrKind::SocketV6 => "invalid IPv6 socket address syntax",
         }
+        .fmt(f)
     }
 }
+
+#[stable(feature = "addr_parse_error_error", since = "1.4.0")]
+impl Error for AddrParseError {}
diff --git a/library/core/src/num/dec2flt/mod.rs b/library/core/src/num/dec2flt/mod.rs
index 3118a6e5ca62e..dd4eccd24de03 100644
--- a/library/core/src/num/dec2flt/mod.rs
+++ b/library/core/src/num/dec2flt/mod.rs
@@ -219,21 +219,16 @@ enum FloatErrorKind {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl Error for ParseFloatError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        match self.kind {
-            FloatErrorKind::Empty => "cannot parse float from empty string",
-            FloatErrorKind::Invalid => "invalid float literal",
-        }
-    }
-}
+impl Error for ParseFloatError {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Display for ParseFloatError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        #[allow(deprecated)]
-        self.description().fmt(f)
+        match self.kind {
+            FloatErrorKind::Empty => "cannot parse float from empty string",
+            FloatErrorKind::Invalid => "invalid float literal",
+        }
+        .fmt(f)
     }
 }
 
diff --git a/library/core/src/num/error.rs b/library/core/src/num/error.rs
index cfedd465cab0b..faa52329827c1 100644
--- a/library/core/src/num/error.rs
+++ b/library/core/src/num/error.rs
@@ -11,19 +11,13 @@ pub struct TryFromIntError(pub(crate) ());
 
 #[stable(feature = "try_from", since = "1.34.0")]
 impl fmt::Display for TryFromIntError {
-    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-        #[allow(deprecated)]
-        self.description().fmt(fmt)
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        "out of range integral type conversion attempted".fmt(f)
     }
 }
 
 #[stable(feature = "try_from", since = "1.34.0")]
-impl Error for TryFromIntError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "out of range integral type conversion attempted"
-    }
-}
+impl Error for TryFromIntError {}
 
 #[stable(feature = "try_from", since = "1.34.0")]
 #[rustc_const_unstable(feature = "const_try", issue = "74935")]
@@ -128,15 +122,6 @@ impl ParseIntError {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Display for ParseIntError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        #[allow(deprecated)]
-        self.description().fmt(f)
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Error for ParseIntError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
         match self.kind {
             IntErrorKind::Empty => "cannot parse integer from empty string",
             IntErrorKind::InvalidDigit => "invalid digit found in string",
@@ -144,5 +129,9 @@ impl Error for ParseIntError {
             IntErrorKind::NegOverflow => "number too small to fit in target type",
             IntErrorKind::Zero => "number would be zero for non-zero type",
         }
+        .fmt(f)
     }
 }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Error for ParseIntError {}
diff --git a/library/core/src/str/error.rs b/library/core/src/str/error.rs
index 4c8231a2286e1..1677c849ae4bf 100644
--- a/library/core/src/str/error.rs
+++ b/library/core/src/str/error.rs
@@ -124,12 +124,7 @@ impl fmt::Display for Utf8Error {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl Error for Utf8Error {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "invalid utf-8: corrupt contents"
-    }
-}
+impl Error for Utf8Error {}
 
 /// An error returned when parsing a `bool` using [`from_str`] fails
 ///
@@ -147,9 +142,4 @@ impl fmt::Display for ParseBoolError {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl Error for ParseBoolError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "failed to parse bool"
-    }
-}
+impl Error for ParseBoolError {}
diff --git a/library/core/src/time.rs b/library/core/src/time.rs
index 0cc570f4b7335..f37e47f132d54 100644
--- a/library/core/src/time.rs
+++ b/library/core/src/time.rs
@@ -927,7 +927,7 @@ impl Duration {
     pub fn from_secs_f64(secs: f64) -> Duration {
         match Duration::try_from_secs_f64(secs) {
             Ok(v) => v,
-            Err(e) => panic!("{}", e.description()),
+            Err(e) => panic!("{e}"),
         }
     }
 
@@ -964,7 +964,7 @@ impl Duration {
     pub fn from_secs_f32(secs: f32) -> Duration {
         match Duration::try_from_secs_f32(secs) {
             Ok(v) => v,
-            Err(e) => panic!("{}", e.description()),
+            Err(e) => panic!("{e}"),
         }
     }
 
@@ -1445,8 +1445,9 @@ pub struct TryFromFloatSecsError {
     kind: TryFromFloatSecsErrorKind,
 }
 
-impl TryFromFloatSecsError {
-    const fn description(&self) -> &'static str {
+#[stable(feature = "duration_checked_float", since = "1.66.0")]
+impl fmt::Display for TryFromFloatSecsError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.kind {
             TryFromFloatSecsErrorKind::Negative => {
                 "cannot convert float seconds to Duration: value is negative"
@@ -1455,13 +1456,7 @@ impl TryFromFloatSecsError {
                 "cannot convert float seconds to Duration: value is either too big or NaN"
             }
         }
-    }
-}
-
-#[stable(feature = "duration_checked_float", since = "1.66.0")]
-impl fmt::Display for TryFromFloatSecsError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        self.description().fmt(f)
+        .fmt(f)
     }
 }
 
diff --git a/library/std/src/collections/hash/map.rs b/library/std/src/collections/hash/map.rs
index 15a7a770d1a87..fc0fef620e3b6 100644
--- a/library/std/src/collections/hash/map.rs
+++ b/library/std/src/collections/hash/map.rs
@@ -1875,12 +1875,7 @@ impl<'a, K: Debug, V: Debug> fmt::Display for OccupiedError<'a, K, V> {
 }
 
 #[unstable(feature = "map_try_insert", issue = "82766")]
-impl<'a, K: fmt::Debug, V: fmt::Debug> Error for OccupiedError<'a, K, V> {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "key already exists"
-    }
-}
+impl<'a, K: Debug, V: Debug> Error for OccupiedError<'a, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, K, V, S> IntoIterator for &'a HashMap<K, V, S> {
diff --git a/library/std/src/env.rs b/library/std/src/env.rs
index 9f17ff7644557..e457cd61c7596 100644
--- a/library/std/src/env.rs
+++ b/library/std/src/env.rs
@@ -296,15 +296,7 @@ impl fmt::Display for VarError {
 }
 
 #[stable(feature = "env", since = "1.0.0")]
-impl Error for VarError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        match *self {
-            VarError::NotPresent => "environment variable not found",
-            VarError::NotUnicode(..) => "environment variable was not valid unicode",
-        }
-    }
-}
+impl Error for VarError {}
 
 /// Sets the environment variable `key` to the value `value` for the currently running
 /// process.
diff --git a/library/std/src/io/buffered/bufwriter.rs b/library/std/src/io/buffered/bufwriter.rs
index 574eb83dc5649..d569fed24c561 100644
--- a/library/std/src/io/buffered/bufwriter.rs
+++ b/library/std/src/io/buffered/bufwriter.rs
@@ -492,23 +492,15 @@ impl WriterPanicked {
     pub fn into_inner(self) -> Vec<u8> {
         self.buf
     }
-
-    const DESCRIPTION: &'static str =
-        "BufWriter inner writer panicked, what data remains unwritten is not known";
 }
 
 #[stable(feature = "bufwriter_into_parts", since = "1.56.0")]
-impl error::Error for WriterPanicked {
-    #[allow(deprecated, deprecated_in_future)]
-    fn description(&self) -> &str {
-        Self::DESCRIPTION
-    }
-}
+impl error::Error for WriterPanicked {}
 
 #[stable(feature = "bufwriter_into_parts", since = "1.56.0")]
 impl fmt::Display for WriterPanicked {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{}", Self::DESCRIPTION)
+        "BufWriter inner writer panicked, what data remains unwritten is not known".fmt(f)
     }
 }
 
diff --git a/library/std/src/io/buffered/mod.rs b/library/std/src/io/buffered/mod.rs
index 475d877528f7f..e36f2d92108d0 100644
--- a/library/std/src/io/buffered/mod.rs
+++ b/library/std/src/io/buffered/mod.rs
@@ -179,12 +179,7 @@ impl<W> From<IntoInnerError<W>> for Error {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<W: Send + fmt::Debug> error::Error for IntoInnerError<W> {
-    #[allow(deprecated, deprecated_in_future)]
-    fn description(&self) -> &str {
-        error::Error::description(self.error())
-    }
-}
+impl<W: Send + fmt::Debug> error::Error for IntoInnerError<W> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<W> fmt::Display for IntoInnerError<W> {
diff --git a/library/std/src/io/error.rs b/library/std/src/io/error.rs
index dcfa189823f89..57a980d6acdb5 100644
--- a/library/std/src/io/error.rs
+++ b/library/std/src/io/error.rs
@@ -1049,15 +1049,6 @@ impl fmt::Display for Error {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl error::Error for Error {
-    #[allow(deprecated, deprecated_in_future)]
-    fn description(&self) -> &str {
-        match self.repr.data() {
-            ErrorData::Os(..) | ErrorData::Simple(..) => self.kind().as_str(),
-            ErrorData::SimpleMessage(msg) => msg.message,
-            ErrorData::Custom(c) => c.error.description(),
-        }
-    }
-
     #[allow(deprecated)]
     fn cause(&self) -> Option<&dyn error::Error> {
         match self.repr.data() {
diff --git a/library/std/src/os/windows/io/socket.rs b/library/std/src/os/windows/io/socket.rs
index 1c228914de93f..28e972925e667 100644
--- a/library/std/src/os/windows/io/socket.rs
+++ b/library/std/src/os/windows/io/socket.rs
@@ -54,7 +54,7 @@ impl BorrowedSocket<'_> {
     ///
     /// # Safety
     ///
-    /// The resource pointed to by `raw` must remain open for the duration of
+    /// The resource pointed to by `socket` must remain open for the duration of
     /// the returned `BorrowedSocket`, and it must not have the value
     /// `INVALID_SOCKET`.
     #[inline]
diff --git a/library/std/src/path.rs b/library/std/src/path.rs
index 3899fbf86db8c..470d300d2d95b 100644
--- a/library/std/src/path.rs
+++ b/library/std/src/path.rs
@@ -3677,19 +3677,13 @@ impl_cmp_os_str!(<'a> Cow<'a, Path>, OsString);
 
 #[stable(since = "1.7.0", feature = "strip_prefix")]
 impl fmt::Display for StripPrefixError {
-    #[allow(deprecated, deprecated_in_future)]
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        self.description().fmt(f)
+        "prefix not found".fmt(f)
     }
 }
 
 #[stable(since = "1.7.0", feature = "strip_prefix")]
-impl Error for StripPrefixError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "prefix not found"
-    }
-}
+impl Error for StripPrefixError {}
 
 #[unstable(feature = "normalize_lexically", issue = "134694")]
 impl fmt::Display for NormalizeError {
diff --git a/library/std/src/sync/mpsc.rs b/library/std/src/sync/mpsc.rs
index 03d7fddc2faef..f91c26aa22cf8 100644
--- a/library/std/src/sync/mpsc.rs
+++ b/library/std/src/sync/mpsc.rs
@@ -1108,12 +1108,7 @@ impl<T> fmt::Display for SendError<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T> error::Error for SendError<T> {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "sending on a closed channel"
-    }
-}
+impl<T> error::Error for SendError<T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> fmt::Debug for TrySendError<T> {
@@ -1136,15 +1131,7 @@ impl<T> fmt::Display for TrySendError<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T> error::Error for TrySendError<T> {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        match *self {
-            TrySendError::Full(..) => "sending on a full channel",
-            TrySendError::Disconnected(..) => "sending on a closed channel",
-        }
-    }
-}
+impl<T> error::Error for TrySendError<T> {}
 
 #[stable(feature = "mpsc_error_conversions", since = "1.24.0")]
 impl<T> From<SendError<T>> for TrySendError<T> {
@@ -1168,12 +1155,7 @@ impl fmt::Display for RecvError {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl error::Error for RecvError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "receiving on a closed channel"
-    }
-}
+impl error::Error for RecvError {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Display for TryRecvError {
@@ -1186,15 +1168,7 @@ impl fmt::Display for TryRecvError {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl error::Error for TryRecvError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        match *self {
-            TryRecvError::Empty => "receiving on an empty channel",
-            TryRecvError::Disconnected => "receiving on a closed channel",
-        }
-    }
-}
+impl error::Error for TryRecvError {}
 
 #[stable(feature = "mpsc_error_conversions", since = "1.24.0")]
 impl From<RecvError> for TryRecvError {
@@ -1221,15 +1195,7 @@ impl fmt::Display for RecvTimeoutError {
 }
 
 #[stable(feature = "mpsc_recv_timeout_error", since = "1.15.0")]
-impl error::Error for RecvTimeoutError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        match *self {
-            RecvTimeoutError::Timeout => "timed out waiting on channel",
-            RecvTimeoutError::Disconnected => "channel is empty and sending half is closed",
-        }
-    }
-}
+impl error::Error for RecvTimeoutError {}
 
 #[stable(feature = "mpsc_error_conversions", since = "1.24.0")]
 impl From<RecvError> for RecvTimeoutError {
diff --git a/library/std/src/sync/poison.rs b/library/std/src/sync/poison.rs
index 31889dcc10fad..49a71b9ad10bd 100644
--- a/library/std/src/sync/poison.rs
+++ b/library/std/src/sync/poison.rs
@@ -263,12 +263,7 @@ impl<T> fmt::Display for PoisonError<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T> Error for PoisonError<T> {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "poisoned lock: another task failed inside"
-    }
-}
+impl<T> Error for PoisonError<T> {}
 
 impl<T> PoisonError<T> {
     /// Creates a `PoisonError`.
@@ -376,17 +371,6 @@ impl<T> fmt::Display for TryLockError<T> {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> Error for TryLockError<T> {
-    #[allow(deprecated, deprecated_in_future)]
-    fn description(&self) -> &str {
-        match *self {
-            #[cfg(panic = "unwind")]
-            TryLockError::Poisoned(ref p) => p.description(),
-            #[cfg(not(panic = "unwind"))]
-            TryLockError::Poisoned(ref p) => match p._never {},
-            TryLockError::WouldBlock => "try_lock failed because the operation would block",
-        }
-    }
-
     #[allow(deprecated)]
     fn cause(&self) -> Option<&dyn Error> {
         match *self {
diff --git a/library/std/src/sys/net/connection/sgx.rs b/library/std/src/sys/net/connection/sgx.rs
index 242df10bc3270..2389fd1bcb6ca 100644
--- a/library/std/src/sys/net/connection/sgx.rs
+++ b/library/std/src/sys/net/connection/sgx.rs
@@ -452,12 +452,7 @@ pub struct NonIpSockAddr {
     host: String,
 }
 
-impl error::Error for NonIpSockAddr {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "Failed to convert address to SocketAddr"
-    }
-}
+impl error::Error for NonIpSockAddr {}
 
 impl fmt::Display for NonIpSockAddr {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
diff --git a/library/std/src/sys/pal/hermit/os.rs b/library/std/src/sys/pal/hermit/os.rs
index a998c3165e52f..0fe713a503bd0 100644
--- a/library/std/src/sys/pal/hermit/os.rs
+++ b/library/std/src/sys/pal/hermit/os.rs
@@ -1,5 +1,4 @@
 use super::hermit_abi;
-use crate::error::Error as StdError;
 use crate::ffi::{OsStr, OsString};
 use crate::marker::PhantomData;
 use crate::path::{self, PathBuf};
@@ -52,12 +51,7 @@ impl fmt::Display for JoinPathsError {
     }
 }
 
-impl StdError for JoinPathsError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "not supported on hermit yet"
-    }
-}
+impl crate::error::Error for JoinPathsError {}
 
 pub fn current_exe() -> io::Result<PathBuf> {
     unsupported()
diff --git a/library/std/src/sys/pal/sgx/mod.rs b/library/std/src/sys/pal/sgx/mod.rs
index 6e43a79ddec2c..4a297b6823f20 100644
--- a/library/std/src/sys/pal/sgx/mod.rs
+++ b/library/std/src/sys/pal/sgx/mod.rs
@@ -59,8 +59,7 @@ pub fn sgx_ineffective<T>(v: T) -> crate::io::Result<T> {
 
 #[inline]
 pub fn is_interrupted(code: i32) -> bool {
-    use fortanix_sgx_abi::Error;
-    code == Error::Interrupted as _
+    code == fortanix_sgx_abi::Error::Interrupted as _
 }
 
 pub fn decode_error_kind(code: i32) -> ErrorKind {
diff --git a/library/std/src/sys/pal/sgx/os.rs b/library/std/src/sys/pal/sgx/os.rs
index 70f838679c9ca..28d79963ac874 100644
--- a/library/std/src/sys/pal/sgx/os.rs
+++ b/library/std/src/sys/pal/sgx/os.rs
@@ -1,11 +1,10 @@
 use fortanix_sgx_abi::{Error, RESULT_SUCCESS};
 
-use crate::error::Error as StdError;
 use crate::ffi::{OsStr, OsString};
 use crate::marker::PhantomData;
 use crate::path::{self, PathBuf};
 use crate::sys::{decode_error_kind, sgx_ineffective, unsupported};
-use crate::{fmt, io, str};
+use crate::{fmt, io};
 
 pub fn errno() -> i32 {
     RESULT_SUCCESS
@@ -59,12 +58,7 @@ impl fmt::Display for JoinPathsError {
     }
 }
 
-impl StdError for JoinPathsError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "not supported in SGX yet"
-    }
-}
+impl crate::error::Error for JoinPathsError {}
 
 pub fn current_exe() -> io::Result<PathBuf> {
     unsupported()
diff --git a/library/std/src/sys/pal/solid/os.rs b/library/std/src/sys/pal/solid/os.rs
index 8f5976b0592ec..cb6e2cbceae6c 100644
--- a/library/std/src/sys/pal/solid/os.rs
+++ b/library/std/src/sys/pal/solid/os.rs
@@ -1,5 +1,4 @@
 use super::{error, itron, unsupported};
-use crate::error::Error as StdError;
 use crate::ffi::{OsStr, OsString};
 use crate::path::{self, PathBuf};
 use crate::{fmt, io};
@@ -58,12 +57,7 @@ impl fmt::Display for JoinPathsError {
     }
 }
 
-impl StdError for JoinPathsError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "not supported on this platform yet"
-    }
-}
+impl crate::error::Error for JoinPathsError {}
 
 pub fn current_exe() -> io::Result<PathBuf> {
     unsupported()
diff --git a/library/std/src/sys/pal/teeos/os.rs b/library/std/src/sys/pal/teeos/os.rs
index 03f3c72b0229a..512b3e2885bf0 100644
--- a/library/std/src/sys/pal/teeos/os.rs
+++ b/library/std/src/sys/pal/teeos/os.rs
@@ -3,7 +3,6 @@
 use core::marker::PhantomData;
 
 use super::unsupported;
-use crate::error::Error as StdError;
 use crate::ffi::{OsStr, OsString};
 use crate::path::PathBuf;
 use crate::{fmt, io, path};
@@ -62,12 +61,7 @@ impl fmt::Display for JoinPathsError {
     }
 }
 
-impl StdError for JoinPathsError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "not supported on this platform yet"
-    }
-}
+impl crate::error::Error for JoinPathsError {}
 
 pub fn current_exe() -> io::Result<PathBuf> {
     unsupported()
diff --git a/library/std/src/sys/pal/uefi/os.rs b/library/std/src/sys/pal/uefi/os.rs
index bfd4dc81cb44f..aae6cb9e06462 100644
--- a/library/std/src/sys/pal/uefi/os.rs
+++ b/library/std/src/sys/pal/uefi/os.rs
@@ -2,7 +2,6 @@ use r_efi::efi::Status;
 use r_efi::efi::protocols::{device_path, loaded_image_device_path};
 
 use super::{RawOsError, helpers, unsupported_err};
-use crate::error::Error as StdError;
 use crate::ffi::{OsStr, OsString};
 use crate::marker::PhantomData;
 use crate::os::uefi;
@@ -122,7 +121,7 @@ impl fmt::Display for JoinPathsError {
     }
 }
 
-impl StdError for JoinPathsError {}
+impl crate::error::Error for JoinPathsError {}
 
 pub fn current_exe() -> io::Result<PathBuf> {
     let protocol = helpers::image_handle_protocol::<device_path::Protocol>(
diff --git a/library/std/src/sys/pal/unix/os.rs b/library/std/src/sys/pal/unix/os.rs
index 1110b775c0953..81275afa70777 100644
--- a/library/std/src/sys/pal/unix/os.rs
+++ b/library/std/src/sys/pal/unix/os.rs
@@ -7,7 +7,6 @@ mod tests;
 
 use libc::{c_char, c_int, c_void};
 
-use crate::error::Error as StdError;
 use crate::ffi::{CStr, OsStr, OsString};
 use crate::os::unix::prelude::*;
 use crate::path::{self, PathBuf};
@@ -248,12 +247,7 @@ impl fmt::Display for JoinPathsError {
     }
 }
 
-impl StdError for JoinPathsError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "failed to join paths"
-    }
-}
+impl crate::error::Error for JoinPathsError {}
 
 #[cfg(target_os = "aix")]
 pub fn current_exe() -> io::Result<PathBuf> {
diff --git a/library/std/src/sys/pal/unsupported/os.rs b/library/std/src/sys/pal/unsupported/os.rs
index a8ef97ecf67ac..13d2a2044f48a 100644
--- a/library/std/src/sys/pal/unsupported/os.rs
+++ b/library/std/src/sys/pal/unsupported/os.rs
@@ -1,5 +1,4 @@
 use super::unsupported;
-use crate::error::Error as StdError;
 use crate::ffi::{OsStr, OsString};
 use crate::marker::PhantomData;
 use crate::path::{self, PathBuf};
@@ -51,12 +50,7 @@ impl fmt::Display for JoinPathsError {
     }
 }
 
-impl StdError for JoinPathsError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "not supported on this platform yet"
-    }
-}
+impl crate::error::Error for JoinPathsError {}
 
 pub fn current_exe() -> io::Result<PathBuf> {
     unsupported()
diff --git a/library/std/src/sys/pal/wasi/os.rs b/library/std/src/sys/pal/wasi/os.rs
index 672cf70d1a5b2..151ba254ec4cf 100644
--- a/library/std/src/sys/pal/wasi/os.rs
+++ b/library/std/src/sys/pal/wasi/os.rs
@@ -1,6 +1,5 @@
 #![forbid(unsafe_op_in_unsafe_fn)]
 
-use crate::error::Error as StdError;
 use crate::ffi::{CStr, OsStr, OsString};
 use crate::marker::PhantomData;
 use crate::os::wasi::prelude::*;
@@ -105,12 +104,7 @@ impl fmt::Display for JoinPathsError {
     }
 }
 
-impl StdError for JoinPathsError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "not supported on wasm yet"
-    }
-}
+impl crate::error::Error for JoinPathsError {}
 
 pub fn current_exe() -> io::Result<PathBuf> {
     unsupported()
diff --git a/library/std/src/sys/pal/windows/os.rs b/library/std/src/sys/pal/windows/os.rs
index f331282d2d72a..1b3c80c079bef 100644
--- a/library/std/src/sys/pal/windows/os.rs
+++ b/library/std/src/sys/pal/windows/os.rs
@@ -8,7 +8,6 @@ mod tests;
 use super::api;
 #[cfg(not(target_vendor = "uwp"))]
 use super::api::WinError;
-use crate::error::Error as StdError;
 use crate::ffi::{OsStr, OsString};
 use crate::os::windows::ffi::EncodeWide;
 use crate::os::windows::prelude::*;
@@ -162,12 +161,7 @@ impl fmt::Display for JoinPathsError {
     }
 }
 
-impl StdError for JoinPathsError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "failed to join paths"
-    }
-}
+impl crate::error::Error for JoinPathsError {}
 
 pub fn current_exe() -> io::Result<PathBuf> {
     super::fill_utf16_buf(
diff --git a/library/std/src/sys/pal/xous/os.rs b/library/std/src/sys/pal/xous/os.rs
index d612a27d2bdb6..d9b8418e6c33c 100644
--- a/library/std/src/sys/pal/xous/os.rs
+++ b/library/std/src/sys/pal/xous/os.rs
@@ -1,5 +1,4 @@
 use super::unsupported;
-use crate::error::Error as StdError;
 use crate::ffi::{OsStr, OsString};
 use crate::marker::PhantomData;
 use crate::os::xous::ffi::Error as XousError;
@@ -110,12 +109,7 @@ impl fmt::Display for JoinPathsError {
     }
 }
 
-impl StdError for JoinPathsError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "not supported on this platform yet"
-    }
-}
+impl crate::error::Error for JoinPathsError {}
 
 pub fn current_exe() -> io::Result<PathBuf> {
     unsupported()
diff --git a/library/std/src/sys/pal/zkvm/os.rs b/library/std/src/sys/pal/zkvm/os.rs
index a8ef97ecf67ac..13d2a2044f48a 100644
--- a/library/std/src/sys/pal/zkvm/os.rs
+++ b/library/std/src/sys/pal/zkvm/os.rs
@@ -1,5 +1,4 @@
 use super::unsupported;
-use crate::error::Error as StdError;
 use crate::ffi::{OsStr, OsString};
 use crate::marker::PhantomData;
 use crate::path::{self, PathBuf};
@@ -51,12 +50,7 @@ impl fmt::Display for JoinPathsError {
     }
 }
 
-impl StdError for JoinPathsError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "not supported on this platform yet"
-    }
-}
+impl crate::error::Error for JoinPathsError {}
 
 pub fn current_exe() -> io::Result<PathBuf> {
     unsupported()
diff --git a/library/std/src/time.rs b/library/std/src/time.rs
index 07bb41f14961b..84fbb4c2fe4b1 100644
--- a/library/std/src/time.rs
+++ b/library/std/src/time.rs
@@ -717,12 +717,7 @@ impl SystemTimeError {
 }
 
 #[stable(feature = "time2", since = "1.8.0")]
-impl Error for SystemTimeError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "other time was not earlier than self"
-    }
-}
+impl Error for SystemTimeError {}
 
 #[stable(feature = "time2", since = "1.8.0")]
 impl fmt::Display for SystemTimeError {
diff --git a/src/bootstrap/src/core/build_steps/compile.rs b/src/bootstrap/src/core/build_steps/compile.rs
index f7a2dc1421848..a4976139fe96a 100644
--- a/src/bootstrap/src/core/build_steps/compile.rs
+++ b/src/bootstrap/src/core/build_steps/compile.rs
@@ -2031,6 +2031,7 @@ impl Step for Assemble {
 
                 let host_llvm_bin_dir = command(&host_llvm_config)
                     .arg("--bindir")
+                    .cached()
                     .run_capture_stdout(builder)
                     .stdout()
                     .trim()
diff --git a/src/bootstrap/src/core/build_steps/dist.rs b/src/bootstrap/src/core/build_steps/dist.rs
index 3c322256cf277..c1c7f779d394b 100644
--- a/src/bootstrap/src/core/build_steps/dist.rs
+++ b/src/bootstrap/src/core/build_steps/dist.rs
@@ -2269,6 +2269,7 @@ fn maybe_install_llvm(
     {
         trace!("LLVM already built, installing LLVM files");
         let mut cmd = command(host_llvm_config);
+        cmd.cached();
         cmd.arg("--libfiles");
         builder.verbose(|| println!("running {cmd:?}"));
         let files = cmd.run_capture_stdout(builder).stdout();
diff --git a/src/bootstrap/src/core/build_steps/llvm.rs b/src/bootstrap/src/core/build_steps/llvm.rs
index 70259f0d1d7c0..d47c149583899 100644
--- a/src/bootstrap/src/core/build_steps/llvm.rs
+++ b/src/bootstrap/src/core/build_steps/llvm.rs
@@ -486,8 +486,11 @@ impl Step for Llvm {
             let LlvmResult { host_llvm_config, .. } =
                 builder.ensure(Llvm { target: builder.config.host_target });
             if !builder.config.dry_run() {
-                let llvm_bindir =
-                    command(&host_llvm_config).arg("--bindir").run_capture_stdout(builder).stdout();
+                let llvm_bindir = command(&host_llvm_config)
+                    .arg("--bindir")
+                    .cached()
+                    .run_capture_stdout(builder)
+                    .stdout();
                 let host_bin = Path::new(llvm_bindir.trim());
                 cfg.define(
                     "LLVM_TABLEGEN",
@@ -593,7 +596,13 @@ impl Step for Llvm {
 }
 
 pub fn get_llvm_version(builder: &Builder<'_>, llvm_config: &Path) -> String {
-    command(llvm_config).arg("--version").run_capture_stdout(builder).stdout().trim().to_owned()
+    command(llvm_config)
+        .arg("--version")
+        .cached()
+        .run_capture_stdout(builder)
+        .stdout()
+        .trim()
+        .to_owned()
 }
 
 pub fn get_llvm_version_major(builder: &Builder<'_>, llvm_config: &Path) -> u8 {
diff --git a/src/bootstrap/src/core/build_steps/run.rs b/src/bootstrap/src/core/build_steps/run.rs
index c6288f6384718..d9de6b7ef96bf 100644
--- a/src/bootstrap/src/core/build_steps/run.rs
+++ b/src/bootstrap/src/core/build_steps/run.rs
@@ -5,13 +5,14 @@
 
 use std::path::PathBuf;
 
+use build_helper::exit;
 use clap_complete::{Generator, shells};
 
 use crate::core::build_steps::dist::distdir;
 use crate::core::build_steps::test;
 use crate::core::build_steps::tool::{self, RustcPrivateCompilers, SourceType, Tool};
 use crate::core::build_steps::vendor::{Vendor, default_paths_to_vendor};
-use crate::core::builder::{Builder, Kind, RunConfig, ShouldRun, Step};
+use crate::core::builder::{Builder, Kind, RunConfig, ShouldRun, Step, StepMetadata};
 use crate::core::config::TargetSelection;
 use crate::core::config::flags::get_completion;
 use crate::utils::exec::command;
@@ -100,8 +101,17 @@ impl Step for ReplaceVersionPlaceholder {
     }
 }
 
+/// Invoke the Miri tool on a specified file.
+///
+/// Note that Miri always executed on the host, as it is an interpreter.
+/// That means that `x run miri --target FOO` will build miri for the host,
+/// prepare a miri sysroot for the target `FOO` and then execute miri with
+/// the target `FOO`.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Miri {
+    /// The build compiler that will build miri and the target compiler to which miri links.
+    compilers: RustcPrivateCompilers,
+    /// The target which will miri interpret.
     target: TargetSelection,
 }
 
@@ -113,14 +123,9 @@ impl Step for Miri {
     }
 
     fn make_run(run: RunConfig<'_>) {
-        run.builder.ensure(Miri { target: run.target });
-    }
-
-    fn run(self, builder: &Builder<'_>) {
-        let host = builder.build.host_target;
-        let target = self.target;
+        let builder = run.builder;
 
-        // `x run` uses stage 0 by default but miri does not work well with stage 0.
+        // `x run` uses stage 0 by default, but miri does not work well with stage 0.
         // Change the stage to 1 if it's not set explicitly.
         let stage = if builder.config.is_explicit_stage() || builder.top_stage >= 1 {
             builder.top_stage
@@ -129,14 +134,22 @@ impl Step for Miri {
         };
 
         if stage == 0 {
-            eprintln!("miri cannot be run at stage 0");
-            std::process::exit(1);
+            eprintln!("ERROR: miri cannot be run at stage 0");
+            exit!(1);
         }
 
-        // This compiler runs on the host, we'll just use it for the target.
-        let compilers = RustcPrivateCompilers::new(builder, stage, target);
-        let miri_build = builder.ensure(tool::Miri::from_compilers(compilers));
-        let host_compiler = miri_build.build_compiler;
+        // Miri always runs on the host, because it can interpret code for any target
+        let compilers = RustcPrivateCompilers::new(builder, stage, builder.host_target);
+
+        run.builder.ensure(Miri { compilers, target: run.target });
+    }
+
+    fn run(self, builder: &Builder<'_>) {
+        let host = builder.build.host_target;
+        let compilers = self.compilers;
+        let target = self.target;
+
+        builder.ensure(tool::Miri::from_compilers(compilers));
 
         // Get a target sysroot for Miri.
         let miri_sysroot =
@@ -147,7 +160,7 @@ impl Step for Miri {
         // add_rustc_lib_path does not add the path that contains librustc_driver-<...>.so.
         let mut miri = tool::prepare_tool_cargo(
             builder,
-            host_compiler,
+            compilers.build_compiler(),
             Mode::ToolRustc,
             host,
             Kind::Run,
@@ -167,6 +180,10 @@ impl Step for Miri {
 
         miri.into_cmd().run(builder);
     }
+
+    fn metadata(&self) -> Option<StepMetadata> {
+        Some(StepMetadata::run("miri", self.target).built_by(self.compilers.build_compiler()))
+    }
 }
 
 #[derive(Debug, Clone, Hash, PartialEq, Eq)]
diff --git a/src/bootstrap/src/core/build_steps/test.rs b/src/bootstrap/src/core/build_steps/test.rs
index b52707032ba14..a6156cad6fc4c 100644
--- a/src/bootstrap/src/core/build_steps/test.rs
+++ b/src/bootstrap/src/core/build_steps/test.rs
@@ -2043,6 +2043,7 @@ HELP: You can add it into `bootstrap.toml` in `rust.codegen-backends = [{name:?}
             if !builder.config.dry_run() {
                 let llvm_version = get_llvm_version(builder, &host_llvm_config);
                 let llvm_components = command(&host_llvm_config)
+                    .cached()
                     .arg("--components")
                     .run_capture_stdout(builder)
                     .stdout();
@@ -2062,8 +2063,11 @@ HELP: You can add it into `bootstrap.toml` in `rust.codegen-backends = [{name:?}
             // separate compilations. We can add LLVM's library path to the
             // rustc args as a workaround.
             if !builder.config.dry_run() && suite.ends_with("fulldeps") {
-                let llvm_libdir =
-                    command(&host_llvm_config).arg("--libdir").run_capture_stdout(builder).stdout();
+                let llvm_libdir = command(&host_llvm_config)
+                    .cached()
+                    .arg("--libdir")
+                    .run_capture_stdout(builder)
+                    .stdout();
                 let link_llvm = if target.is_msvc() {
                     format!("-Clink-arg=-LIBPATH:{llvm_libdir}")
                 } else {
diff --git a/src/bootstrap/src/core/build_steps/tool.rs b/src/bootstrap/src/core/build_steps/tool.rs
index c10b82536467d..b62c9a906b79c 100644
--- a/src/bootstrap/src/core/build_steps/tool.rs
+++ b/src/bootstrap/src/core/build_steps/tool.rs
@@ -1581,10 +1581,6 @@ impl Builder<'_> {
     /// `host`.
     pub fn tool_cmd(&self, tool: Tool) -> BootstrapCommand {
         let mut cmd = command(self.tool_exe(tool));
-
-        // Do not cache tool invocations, as they can have side effects
-        cmd.do_not_cache();
-
         let compiler = self.compiler(0, self.config.host_target);
         let host = &compiler.host;
         // Prepares the `cmd` provided to be able to run the `compiler` provided.
diff --git a/src/bootstrap/src/core/build_steps/vendor.rs b/src/bootstrap/src/core/build_steps/vendor.rs
index 7b860ceb94325..0e9d4e7e32ba1 100644
--- a/src/bootstrap/src/core/build_steps/vendor.rs
+++ b/src/bootstrap/src/core/build_steps/vendor.rs
@@ -19,6 +19,7 @@ pub const VENDOR_DIR: &str = "vendor";
 pub fn default_paths_to_vendor(builder: &Builder<'_>) -> Vec<(PathBuf, Vec<&'static str>)> {
     [
         ("src/tools/cargo/Cargo.toml", vec!["src/tools/cargo"]),
+        ("src/tools/clippy/clippy_test_deps/Cargo.toml", vec![]),
         ("src/tools/rust-analyzer/Cargo.toml", vec![]),
         ("compiler/rustc_codegen_cranelift/Cargo.toml", vec![]),
         ("compiler/rustc_codegen_gcc/Cargo.toml", vec![]),
diff --git a/src/bootstrap/src/core/builder/cargo.rs b/src/bootstrap/src/core/builder/cargo.rs
index 721924034123e..9c417952a5f7d 100644
--- a/src/bootstrap/src/core/builder/cargo.rs
+++ b/src/bootstrap/src/core/builder/cargo.rs
@@ -132,10 +132,7 @@ impl Cargo {
     }
 
     pub fn into_cmd(self) -> BootstrapCommand {
-        let mut cmd: BootstrapCommand = self.into();
-        // Disable caching for commands originating from Cargo-related operations.
-        cmd.do_not_cache();
-        cmd
+        self.into()
     }
 
     /// Same as [`Cargo::new`] except this one doesn't configure the linker with
@@ -1085,7 +1082,7 @@ impl Builder<'_> {
             && let Some(llvm_config) = self.llvm_config(target)
         {
             let llvm_libdir =
-                command(llvm_config).arg("--libdir").run_capture_stdout(self).stdout();
+                command(llvm_config).cached().arg("--libdir").run_capture_stdout(self).stdout();
             if target.is_msvc() {
                 rustflags.arg(&format!("-Clink-arg=-LIBPATH:{llvm_libdir}"));
             } else {
diff --git a/src/bootstrap/src/core/builder/mod.rs b/src/bootstrap/src/core/builder/mod.rs
index 4f1bed13c13e7..0db53a46a344e 100644
--- a/src/bootstrap/src/core/builder/mod.rs
+++ b/src/bootstrap/src/core/builder/mod.rs
@@ -182,6 +182,10 @@ impl StepMetadata {
         Self::new(name, target, Kind::Test)
     }
 
+    pub fn run(name: &str, target: TargetSelection) -> Self {
+        Self::new(name, target, Kind::Run)
+    }
+
     fn new(name: &str, target: TargetSelection, kind: Kind) -> Self {
         Self { name: name.to_string(), kind, target, built_by: None, stage: None, metadata: None }
     }
diff --git a/src/bootstrap/src/core/builder/tests.rs b/src/bootstrap/src/core/builder/tests.rs
index 5260b43f706cd..fca52268222c5 100644
--- a/src/bootstrap/src/core/builder/tests.rs
+++ b/src/bootstrap/src/core/builder/tests.rs
@@ -2372,6 +2372,24 @@ mod snapshot {
         [dist] src <>
         ");
     }
+
+    // Check that `x run miri --target FOO` actually builds miri for the host.
+    #[test]
+    fn run_miri() {
+        let ctx = TestCtx::new();
+        insta::assert_snapshot!(
+            ctx.config("run")
+                .path("miri")
+                .stage(1)
+                .targets(&[TEST_TRIPLE_1])
+                .render_steps(), @r"
+        [build] llvm <host>
+        [build] rustc 0 <host> -> rustc 1 <host>
+        [build] rustc 0 <host> -> miri 1 <host>
+        [build] rustc 0 <host> -> cargo-miri 1 <host>
+        [run] rustc 0 <host> -> miri 1 <target1>
+        ");
+    }
 }
 
 struct ExecutedSteps {
diff --git a/src/bootstrap/src/core/config/config.rs b/src/bootstrap/src/core/config/config.rs
index e5c2e3c64b803..3e9c8ccb4fa0c 100644
--- a/src/bootstrap/src/core/config/config.rs
+++ b/src/bootstrap/src/core/config/config.rs
@@ -960,8 +960,8 @@ impl Config {
             Subcommand::Dist => flags_stage.or(build_dist_stage).unwrap_or(2),
             Subcommand::Install => flags_stage.or(build_install_stage).unwrap_or(2),
             Subcommand::Perf { .. } => flags_stage.unwrap_or(1),
-            // These are all bootstrap tools, which don't depend on the compiler.
-            // The stage we pass shouldn't matter, but use 0 just in case.
+            // Most of the run commands execute bootstrap tools, which don't depend on the compiler.
+            // Other commands listed here should always use bootstrap tools.
             Subcommand::Clean { .. }
             | Subcommand::Run { .. }
             | Subcommand::Setup { .. }
diff --git a/src/bootstrap/src/core/sanity.rs b/src/bootstrap/src/core/sanity.rs
index 4916ebbd61098..099ec4883972f 100644
--- a/src/bootstrap/src/core/sanity.rs
+++ b/src/bootstrap/src/core/sanity.rs
@@ -34,6 +34,7 @@ pub struct Finder {
 // Targets can be removed from this list once they are present in the stage0 compiler (usually by updating the beta compiler of the bootstrap).
 const STAGE0_MISSING_TARGETS: &[&str] = &[
     "armv7a-vex-v5",
+    "riscv64a23-unknown-linux-gnu",
     // just a dummy comment so the list doesn't get onelined
     "aarch64_be-unknown-hermit",
     "aarch64_be-unknown-none-softfloat",
diff --git a/src/bootstrap/src/utils/exec.rs b/src/bootstrap/src/utils/exec.rs
index 9a536f75ab741..e09f3086b777c 100644
--- a/src/bootstrap/src/utils/exec.rs
+++ b/src/bootstrap/src/utils/exec.rs
@@ -264,8 +264,11 @@ impl<'a> BootstrapCommand {
         self
     }
 
-    pub fn do_not_cache(&mut self) -> &mut Self {
-        self.should_cache = false;
+    /// Cache the command. If it will be executed multiple times with the exact same arguments
+    /// and environment variables in the same bootstrap invocation, the previous result will be
+    /// loaded from memory.
+    pub fn cached(&mut self) -> &mut Self {
+        self.should_cache = true;
         self
     }
 
@@ -425,7 +428,7 @@ impl From<Command> for BootstrapCommand {
     fn from(command: Command) -> Self {
         let program = command.get_program().to_owned();
         Self {
-            should_cache: true,
+            should_cache: false,
             command,
             failure_behavior: BehaviorOnFailure::Exit,
             run_in_dry_run: false,
diff --git a/src/bootstrap/src/utils/helpers.rs b/src/bootstrap/src/utils/helpers.rs
index 451482717b6c1..e802c0214ddcb 100644
--- a/src/bootstrap/src/utils/helpers.rs
+++ b/src/bootstrap/src/utils/helpers.rs
@@ -510,6 +510,8 @@ pub fn check_cfg_arg(name: &str, values: Option<&[&str]>) -> String {
 #[track_caller]
 pub fn git(source_dir: Option<&Path>) -> BootstrapCommand {
     let mut git = command("git");
+    // git commands are almost always read-only, so cache them by default
+    git.cached();
 
     if let Some(source_dir) = source_dir {
         git.current_dir(source_dir);
diff --git a/src/doc/rustc/src/SUMMARY.md b/src/doc/rustc/src/SUMMARY.md
index b53494ed98d4a..e0d637a2a67fc 100644
--- a/src/doc/rustc/src/SUMMARY.md
+++ b/src/doc/rustc/src/SUMMARY.md
@@ -49,6 +49,7 @@
     - [aarch64-nintendo-switch-freestanding](platform-support/aarch64-nintendo-switch-freestanding.md)
     - [aarch64-unknown-linux-musl](platform-support/aarch64-unknown-linux-musl.md)
     - [aarch64_be-unknown-none-softfloat](platform-support/aarch64_be-unknown-none-softfloat.md)
+    - [aarch64_be-unknown-linux-musl](platform-support/aarch64_be-unknown-linux-musl.md)
     - [amdgcn-amd-amdhsa](platform-support/amdgcn-amd-amdhsa.md)
     - [armeb-unknown-linux-gnueabi](platform-support/armeb-unknown-linux-gnueabi.md)
     - [arm-none-eabi](platform-support/arm-none-eabi.md)
@@ -106,6 +107,7 @@
     - [riscv32imac-unknown-xous-elf](platform-support/riscv32imac-unknown-xous-elf.md)
     - [riscv64gc-unknown-linux-gnu](platform-support/riscv64gc-unknown-linux-gnu.md)
     - [riscv64gc-unknown-linux-musl](platform-support/riscv64gc-unknown-linux-musl.md)
+    - [riscv64a23-unknown-linux-gnu](platform-support/riscv64a23-unknown-linux-gnu.md)
     - [s390x-unknown-linux-gnu](platform-support/s390x-unknown-linux-gnu.md)
     - [s390x-unknown-linux-musl](platform-support/s390x-unknown-linux-musl.md)
     - [sparc-unknown-none-elf](./platform-support/sparc-unknown-none-elf.md)
diff --git a/src/doc/rustc/src/images/image1.png b/src/doc/rustc/src/images/image1.png
index 0da45e56620da..3aad63593897f 100644
Binary files a/src/doc/rustc/src/images/image1.png and b/src/doc/rustc/src/images/image1.png differ
diff --git a/src/doc/rustc/src/images/image2.png b/src/doc/rustc/src/images/image2.png
index a9cf23f873772..085b1c490b866 100644
Binary files a/src/doc/rustc/src/images/image2.png and b/src/doc/rustc/src/images/image2.png differ
diff --git a/src/doc/rustc/src/images/image3.png b/src/doc/rustc/src/images/image3.png
index 844a2fe67472d..ee332f51055df 100644
Binary files a/src/doc/rustc/src/images/image3.png and b/src/doc/rustc/src/images/image3.png differ
diff --git a/src/doc/rustc/src/images/llvm-cov-show-01.png b/src/doc/rustc/src/images/llvm-cov-show-01.png
index 35f04594347a3..ce4dec128b614 100644
Binary files a/src/doc/rustc/src/images/llvm-cov-show-01.png and b/src/doc/rustc/src/images/llvm-cov-show-01.png differ
diff --git a/src/doc/rustc/src/platform-support.md b/src/doc/rustc/src/platform-support.md
index 3bf8799429717..22d32a29b36c1 100644
--- a/src/doc/rustc/src/platform-support.md
+++ b/src/doc/rustc/src/platform-support.md
@@ -273,6 +273,7 @@ target | std | host | notes
 [`aarch64_be-unknown-hermit`](platform-support/hermit.md) | ✓ |  | ARM64 Hermit (big-endian)
 `aarch64_be-unknown-linux-gnu` | ✓ | ✓ | ARM64 Linux (big-endian)
 `aarch64_be-unknown-linux-gnu_ilp32` | ✓ | ✓ | ARM64 Linux (big-endian, ILP32 ABI)
+[`aarch64_be-unknown-linux-musl`](platform-support/aarch64_be-unknown-linux-musl.md) | ✓ | ✓ | ARM64 Linux (big-endian) with musl-libc 1.2.5
 [`aarch64_be-unknown-netbsd`](platform-support/netbsd.md) | ✓ | ✓ | ARM64 NetBSD (big-endian)
 [`aarch64_be-unknown-none-softfloat`](platform-support/aarch64_be-unknown-none-softfloat.md) | * |  | Bare big-endian ARM64, softfloat
 [`amdgcn-amd-amdhsa`](platform-support/amdgcn-amd-amdhsa.md) | * |  | `-Ctarget-cpu=gfx...` to specify [the AMD GPU] to compile for
@@ -391,6 +392,7 @@ target | std | host | notes
 [`riscv64gc-unknown-nuttx-elf`](platform-support/nuttx.md) | ✓ |  | RISC-V 64bit with NuttX
 [`riscv64gc-unknown-openbsd`](platform-support/openbsd.md) | ✓ | ✓ | OpenBSD/riscv64
 [`riscv64imac-unknown-nuttx-elf`](platform-support/nuttx.md) | ✓ |  | RISC-V 64bit with NuttX
+[`riscv64a23-unknown-linux-gnu`](platform-support/riscv64a23-unknown-linux-gnu.md) | ✓ | ✓ | RISC-V Linux (kernel 6.8.0+, glibc 2.39)
 [`s390x-unknown-linux-musl`](platform-support/s390x-unknown-linux-musl.md) | ✓ |  | S390x Linux (kernel 3.2, musl 1.2.3)
 `sparc-unknown-linux-gnu` | ✓ |  | 32-bit SPARC Linux
 [`sparc-unknown-none-elf`](./platform-support/sparc-unknown-none-elf.md) | * |  | Bare 32-bit SPARC V7+
diff --git a/src/doc/rustc/src/platform-support/aarch64_be-unknown-linux-musl.md b/src/doc/rustc/src/platform-support/aarch64_be-unknown-linux-musl.md
new file mode 100644
index 0000000000000..3e816dc8bfb31
--- /dev/null
+++ b/src/doc/rustc/src/platform-support/aarch64_be-unknown-linux-musl.md
@@ -0,0 +1,49 @@
+# aarch64_be-unknown-linux-musl
+
+**Tier: 3**
+
+ARM64 Linux (big-endian) with musl-libc.
+
+## Target maintainers
+
+[@neuschaefer](https://github.com/neuschaefer)
+[@Gelbpunkt](https://github.com/Gelbpunkt)
+
+## Requirements
+
+The target requires a `aarch64_be-*-linux-musl` toolchain, which likely has to
+be built from source because this is a rare combination.  [Buildroot] provides
+a way of doing so:
+
+- select _Target options_ → _Target Architecture_ → _AArch64 (big endian)_
+- select _Toolchain_ → _C library_ → _musl_
+- select _Toolchain_ → _Enable C++ support_
+
+Host tools are supported.
+
+[Buildroot]: https://buildroot.org/
+
+
+## Building the target
+
+The target can be enabled in bootstrap.toml:
+
+```toml
+[build]
+target = ["aarch64_be-unknown-linux-musl"]
+
+[target.aarch64_be-unknown-linux-musl]
+cc          = "/path/to/buildroot/host/bin/aarch64_be-buildroot-linux-musl-cc"
+cxx         = "/path/to/buildroot/host/bin/aarch64_be-buildroot-linux-musl-c++"
+linker      = "/path/to/buildroot/host/bin/aarch64_be-buildroot-linux-musl-cc"
+ar          = "/path/to/buildroot/host/bin/aarch64_be-buildroot-linux-musl-ar"
+ranlib      = "/path/to/buildroot/host/bin/aarch64_be-buildroot-linux-musl-ranlib"
+musl-root   = "/path/to/buildroot/staging"
+runner      = "qemu-aarch64_be -L /path/to/buildroot/target"
+crt-static  = "/path/to/buildroot/target"
+```
+
+
+## Testing
+
+Binaries can be run under `qemu-aarch64_be` or under a big-endian Linux kernel.
diff --git a/src/doc/rustc/src/platform-support/riscv64a23-unknown-linux-gnu.md b/src/doc/rustc/src/platform-support/riscv64a23-unknown-linux-gnu.md
new file mode 100644
index 0000000000000..2cbaaa8665410
--- /dev/null
+++ b/src/doc/rustc/src/platform-support/riscv64a23-unknown-linux-gnu.md
@@ -0,0 +1,41 @@
+# `riscv64a23-unknown-linux-gnu`
+
+**Tier: 3**
+
+RISC-V target using the ratified [RVA23 Profile](https://github.com/riscv/riscv-profiles/blob/main/src/rva23-profile.adoc).
+This target will enable all mandary features of rva23u64 by default.
+
+## Target maintainers
+
+[@ZhongyaoChen](https://github.com/ZhongyaoChen)
+[@CaiWeiran](https://github.com/CaiWeiran)
+
+## Requirements
+
+This target can be sucessfully build on the following platform: ubuntu 24.04 (Linux Kernel version 6.8.0, glibc 2.39).
+
+Other platforms may work, but are not tested. Please contanct if you encounter any issues.
+
+## Building the target
+
+Tier-3 target is not distributed through `rustup`.
+
+You need to build your own Rust, the target can be build with:
+
+```bash
+./x build --target riscv64a23-unknown-linux-gnu
+```
+
+## Building Rust programs
+
+Add the toolchain:
+
+```bash
+rustup toolchain link rva23-toolchain {path-to-rust}/build/host/stage2
+```
+
+Then cross compile crates with:
+
+```bash
+RUSTFLAGS="-C linker=riscv64-linux-gnu-gcc" cargo +rva23-toolchain build --target=riscv64a23-unknown-linux-gnu
+```
diff --git a/src/doc/rustdoc/src/images/collapsed-long-item.png b/src/doc/rustdoc/src/images/collapsed-long-item.png
index c382870c64a65..6de759fbeb9d4 100644
Binary files a/src/doc/rustdoc/src/images/collapsed-long-item.png and b/src/doc/rustdoc/src/images/collapsed-long-item.png differ
diff --git a/src/doc/rustdoc/src/images/collapsed-trait-impls.png b/src/doc/rustdoc/src/images/collapsed-trait-impls.png
index f685656e09a9c..96cc7db67986c 100644
Binary files a/src/doc/rustdoc/src/images/collapsed-trait-impls.png and b/src/doc/rustdoc/src/images/collapsed-trait-impls.png differ
diff --git a/src/etc/installer/gfx/rust-logo.png b/src/etc/installer/gfx/rust-logo.png
index 99ee7507fa2fb..49d8d0d9485ed 100644
Binary files a/src/etc/installer/gfx/rust-logo.png and b/src/etc/installer/gfx/rust-logo.png differ
diff --git a/src/librustdoc/html/static/images/favicon-32x32.png b/src/librustdoc/html/static/images/favicon-32x32.png
index 69b8613ce1506..0670c4dabb0f8 100644
Binary files a/src/librustdoc/html/static/images/favicon-32x32.png and b/src/librustdoc/html/static/images/favicon-32x32.png differ
diff --git a/tests/assembly-llvm/targets/targets-elf.rs b/tests/assembly-llvm/targets/targets-elf.rs
index 79347d0bbf644..c935a75a6901d 100644
--- a/tests/assembly-llvm/targets/targets-elf.rs
+++ b/tests/assembly-llvm/targets/targets-elf.rs
@@ -10,6 +10,9 @@
 //@ revisions: aarch64_be_unknown_linux_gnu_ilp32
 //@ [aarch64_be_unknown_linux_gnu_ilp32] compile-flags: --target aarch64_be-unknown-linux-gnu_ilp32
 //@ [aarch64_be_unknown_linux_gnu_ilp32] needs-llvm-components: aarch64
+//@ revisions: aarch64_be_unknown_linux_musl
+//@ [aarch64_be_unknown_linux_musl] compile-flags: --target aarch64_be-unknown-linux-musl
+//@ [aarch64_be_unknown_linux_musl] needs-llvm-components: aarch64
 //@ revisions: aarch64_be_unknown_netbsd
 //@ [aarch64_be_unknown_netbsd] compile-flags: --target aarch64_be-unknown-netbsd
 //@ [aarch64_be_unknown_netbsd] needs-llvm-components: aarch64
@@ -481,6 +484,9 @@
 //@ revisions: riscv64gc_unknown_linux_gnu
 //@ [riscv64gc_unknown_linux_gnu] compile-flags: --target riscv64gc-unknown-linux-gnu
 //@ [riscv64gc_unknown_linux_gnu] needs-llvm-components: riscv
+//@ revisions: riscv64a23_unknown_linux_gnu
+//@ [riscv64a23_unknown_linux_gnu] compile-flags: --target riscv64a23-unknown-linux-gnu
+//@ [riscv64a23_unknown_linux_gnu] needs-llvm-components: riscv
 //@ revisions: riscv64gc_unknown_linux_musl
 //@ [riscv64gc_unknown_linux_musl] compile-flags: --target riscv64gc-unknown-linux-musl
 //@ [riscv64gc_unknown_linux_musl] needs-llvm-components: riscv
diff --git a/tests/ui/check-cfg/target_feature.stderr b/tests/ui/check-cfg/target_feature.stderr
index f64481473921a..258f21324661b 100644
--- a/tests/ui/check-cfg/target_feature.stderr
+++ b/tests/ui/check-cfg/target_feature.stderr
@@ -243,6 +243,7 @@ LL |     cfg!(target_feature = "_UNEXPECTED_VALUE");
 `relax`
 `relaxed-simd`
 `rtm`
+`rva23u64`
 `sb`
 `scq`
 `sha`
@@ -304,6 +305,7 @@ LL |     cfg!(target_feature = "_UNEXPECTED_VALUE");
 `ssve-fp8dot2`
 `ssve-fp8dot4`
 `ssve-fp8fma`
+`supm`
 `sve`
 `sve-b16b16`
 `sve2`
diff --git a/tests/ui/const-generics/adt_const_params/const_param_ty_bad.stderr b/tests/ui/const-generics/adt_const_params/const_param_ty_bad.stderr
index 4c8a5e46751c9..c05584ef909ac 100644
--- a/tests/ui/const-generics/adt_const_params/const_param_ty_bad.stderr
+++ b/tests/ui/const-generics/adt_const_params/const_param_ty_bad.stderr
@@ -32,8 +32,9 @@ LL | fn check(_: impl std::marker::UnsizedConstParamTy) {}
    |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
 help: use parentheses to call this closure
    |
-LL |     check(|| {}());
-   |                ++
+LL -     check(|| {});
+LL +     check((|| {})());
+   |
 
 error[E0277]: `fn()` can't be used as a const parameter type
   --> $DIR/const_param_ty_bad.rs:9:11
diff --git a/tests/ui/resolve/issue-102946.rs b/tests/ui/resolve/issue-102946.rs
index c6feca6f32f60..8d90e61bb5d3f 100644
--- a/tests/ui/resolve/issue-102946.rs
+++ b/tests/ui/resolve/issue-102946.rs
@@ -1,7 +1,6 @@
 impl Error for str::Utf8Error {
     //~^ ERROR cannot find trait `Error` in this scope
     //~| ERROR ambiguous associated type
-    fn description(&self)  {}
 }
 
 fn main() {}
diff --git a/tests/ui/suggestions/use-parentheses-to-call-closure-issue-145404.fixed b/tests/ui/suggestions/use-parentheses-to-call-closure-issue-145404.fixed
new file mode 100644
index 0000000000000..2835743fca201
--- /dev/null
+++ b/tests/ui/suggestions/use-parentheses-to-call-closure-issue-145404.fixed
@@ -0,0 +1,13 @@
+//@ run-rustfix
+
+use std::fmt::Display;
+
+struct S;
+
+impl S {
+    fn call(&self, _: impl Display) {}
+}
+
+fn main() {
+    S.call((|| "hello")()); //~ ERROR [E0277]
+}
diff --git a/tests/ui/suggestions/use-parentheses-to-call-closure-issue-145404.rs b/tests/ui/suggestions/use-parentheses-to-call-closure-issue-145404.rs
new file mode 100644
index 0000000000000..848629a67001a
--- /dev/null
+++ b/tests/ui/suggestions/use-parentheses-to-call-closure-issue-145404.rs
@@ -0,0 +1,13 @@
+//@ run-rustfix
+
+use std::fmt::Display;
+
+struct S;
+
+impl S {
+    fn call(&self, _: impl Display) {}
+}
+
+fn main() {
+    S.call(|| "hello"); //~ ERROR [E0277]
+}
diff --git a/tests/ui/suggestions/use-parentheses-to-call-closure-issue-145404.stderr b/tests/ui/suggestions/use-parentheses-to-call-closure-issue-145404.stderr
new file mode 100644
index 0000000000000..cb6df5af7fb16
--- /dev/null
+++ b/tests/ui/suggestions/use-parentheses-to-call-closure-issue-145404.stderr
@@ -0,0 +1,23 @@
+error[E0277]: `{closure@$DIR/use-parentheses-to-call-closure-issue-145404.rs:12:12: 12:14}` doesn't implement `std::fmt::Display`
+  --> $DIR/use-parentheses-to-call-closure-issue-145404.rs:12:12
+   |
+LL |     S.call(|| "hello");
+   |       ---- ^^^^^^^^^^ unsatisfied trait bound
+   |       |
+   |       required by a bound introduced by this call
+   |
+   = help: the trait `std::fmt::Display` is not implemented for closure `{closure@$DIR/use-parentheses-to-call-closure-issue-145404.rs:12:12: 12:14}`
+note: required by a bound in `S::call`
+  --> $DIR/use-parentheses-to-call-closure-issue-145404.rs:8:28
+   |
+LL |     fn call(&self, _: impl Display) {}
+   |                            ^^^^^^^ required by this bound in `S::call`
+help: use parentheses to call this closure
+   |
+LL -     S.call(|| "hello");
+LL +     S.call((|| "hello")());
+   |
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/type-alias-impl-trait/issue-87455-static-lifetime-ice.rs b/tests/ui/type-alias-impl-trait/issue-87455-static-lifetime-ice.rs
index 987fad2efeadb..476babdfb0512 100644
--- a/tests/ui/type-alias-impl-trait/issue-87455-static-lifetime-ice.rs
+++ b/tests/ui/type-alias-impl-trait/issue-87455-static-lifetime-ice.rs
@@ -1,6 +1,6 @@
 //@ check-pass
 
-use std::error::Error as StdError;
+use std::error::Error;
 use std::pin::Pin;
 use std::task::{Context, Poll};
 
@@ -51,7 +51,7 @@ impl<S> Stream for SseKeepAlive<S>
 where
     S: TryStream + Send + 'static,
     S::Ok: ServerSentEvent,
-    S::Error: StdError + Send + Sync + 'static,
+    S::Error: Error + Send + Sync + 'static,
 {
     type Item = Result<SseComment<&'static str>, ()>;
     fn poll_next(self: Pin<&mut Self>, _cx: &mut Context) -> Poll<Option<Self::Item>> {
@@ -65,7 +65,7 @@ pub fn keep<S>(
 where
     S: TryStream + Send + 'static,
     S::Ok: ServerSentEvent + Send,
-    S::Error: StdError + Send + Sync + 'static,
+    S::Error: Error + Send + Sync + 'static,
 {
     SseKeepAlive { event_stream }
 }