Voila

compiler/rustc_lint/messages.ftl

@@ -192,13 +192,9 @@ lint_redundant_semicolons =
         *[false] this semicolon
     }
 
-lint_useless_send_constraint =
-    constraining a reference to `Send` without `Sync` is useless, consider {$only_trait ->
-        [true] replacing it with `Any`
-        *[false] removing it
-    }
+lint_useless_send_constraint = constraining a reference to `Send` is meaningless
     .suggestion = {$only_trait ->
-        [true] replace this with `Any`
+        [true] replace this with `std::any::Any`
         *[false] remove this
     }
 

compiler/rustc_lint/src/useless_send_constraint.rs

@@ -28,30 +28,31 @@ declare_lint_pass!(UselessSendConstraint => [USELESS_SEND_CONSTRAINT]);
 impl<'tcx> LateLintPass<'tcx> for UselessSendConstraint {
     fn check_ty(&mut self, cx: &LateContext<'tcx>, ty: &'tcx hir::Ty<'tcx>) {
         let hir::TyKind::Ref(
+            ..,
             hir::MutTy {
                 ty: hir::Ty {
                     kind: hir::TyKind::TraitObject(bounds, ..),
                     ..
                 },
-                mutbl: hir::Mutability::Not, // only immutable references
+                ..
             },
-            ..
         ) = ty.kind else { return; };
 
         let send = cx.tcx.get_diagnostic_item(sym::Send);
-        let sync = cx.tcx.get_diagnostic_item(sym::Sync);
 
         let send_bound = bounds.iter().find(|b| b.trait_ref.trait_def_id() == send);
-        let sync_bound = bounds.iter().find(|b| b.trait_ref.trait_def_id() == sync);
 
-        if let Some(send_bound) = send_bound && sync_bound.is_none() {
+        if let Some(send_bound) = send_bound {
             let only_trait = bounds.len() == 1;
 
             cx.tcx.emit_spanned_lint(
                 USELESS_SEND_CONSTRAINT,
                 send_bound.trait_ref.hir_ref_id, // is this correct?
                 send_bound.span,
-                UselessSendConstraintDiag { only_trait, suggestion: send_bound.span },
+                UselessSendConstraintDiag {
+                    only_trait,
+                    suggestion: send_bound.span,
+                },
             )
         }
     }

library/std/src/io/error.rs

@@ -769,7 +769,7 @@ impl Error {
     #[stable(feature = "io_error_inner", since = "1.3.0")]
     #[must_use]
     #[inline]
-    pub fn get_mut(&mut self) -> Option<&mut (dyn error::Error + Send + Sync + 'static)> {
+    pub fn get_mut(&mut self) -> Option<&mut (dyn error::Error + Sync + 'static)> {
         match self.repr.data_mut() {
             ErrorData::Os(..) => None,
             ErrorData::Simple(..) => None,