Update the syn crate and adopt let_else in three more places

The syn crate has gained support for let_else syntax in version 1.0.76,
see https://github.com/dtolnay/syn/pull/1057 .

In the three instances that use let_else, we've sent code through an
attr macro, which would create compile errors when there was no
let_else support in syn. To avoid this, we ran
`cargo +nightly update -p syn` for updating the syn crate.

1 files changed, 1 insertions, 3 deletions

diff --git a/compiler/rustc_resolve/src/late/lifetimes.rs b/compiler/rustc_resolve/src/late/lifetimes.rs
index eb6f302a11d..94563400a8b 100644
--- a/compiler/rustc_resolve/src/late/lifetimes.rs
+++ b/compiler/rustc_resolve/src/late/lifetimes.rs
@@ -1057,9 +1057,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                     match param.kind {
                         GenericParamKind::Lifetime { .. } => {
                             let (name, reg) = Region::early(&self.tcx.hir(), &mut index, &param);
-                            let def_id = if let Region::EarlyBound(_, def_id, _) = reg {
-                                def_id
-                            } else {
+                            let Region::EarlyBound(_, def_id, _) = reg else {
                                 bug!();
                             };
                             // We cannot predict what lifetimes are unused in opaque type.