rust-lang · fmease · Jun 17, 2025 · Jun 17, 2025 · Jul 4, 2025 · Jul 3, 2025
diff --git 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/library/alloc/src/boxed.rs b/library/alloc/src/boxed.rs
@@ -2114,11 +2114,6 @@ 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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -4100,11 +4100,6 @@ 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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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/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
@@ -217,21 +217,16 @@ 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
@@ -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")]
@@ -128,21 +122,16 @@ 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",
             IntErrorKind::PosOverflow => "number too large to fit in target type",
             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 {}