Update rust to 1.87.0 (#11938)

We keep the practice of keeping the compiler up to date, pointing to the
latest release. This is done by many other projects in the Rust
ecosystem as well.

The 1.87.0 release marks 10 years of Rust.

[Announcement blog
post](https://blog.rust-lang.org/2025/05/15/Rust-1.87.0/)

Prior update was in #11431

build-tools.Dockerfile

@@ -292,7 +292,7 @@ WORKDIR /home/nonroot
 
 # Rust
 # Please keep the version of llvm (installed above) in sync with rust llvm (`rustc --version --verbose | grep LLVM`)
-ENV RUSTC_VERSION=1.86.0
+ENV RUSTC_VERSION=1.87.0
 ENV RUSTUP_HOME="/home/nonroot/.rustup"
 ENV PATH="/home/nonroot/.cargo/bin:${PATH}"
 ARG RUSTFILT_VERSION=0.2.1

pageserver/src/virtual_file/io_engine.rs

@@ -124,9 +124,7 @@ pub(super) fn epoll_uring_error_to_std(
 ) -> std::io::Error {
     match e {
         tokio_epoll_uring::Error::Op(e) => e,
-        tokio_epoll_uring::Error::System(system) => {
-            std::io::Error::new(std::io::ErrorKind::Other, system)
-        }
+        tokio_epoll_uring::Error::System(system) => std::io::Error::other(system),
     }
 }
 

proxy/src/binary/pg_sni_router.rs

@@ -394,6 +394,7 @@ async fn handle_client(
     }
 }
 
+#[allow(clippy::large_enum_variant)]
 enum Connection {
     Raw(tokio::net::TcpStream),
     Tls(tokio_rustls::client::TlsStream<tokio::net::TcpStream>),

proxy/src/binary/proxy.rs

@@ -862,7 +862,7 @@ async fn configure_redis(
         ("irsa", _) => match (&args.redis_host, args.redis_port) {
             (Some(host), Some(port)) => Some(
                 ConnectionWithCredentialsProvider::new_with_credentials_provider(
-                    host.to_string(),
+                    host.clone(),
                     port,
                     elasticache::CredentialsProvider::new(
                         args.aws_region.clone(),

rust-toolchain.toml

@@ -1,5 +1,5 @@
 [toolchain]
-channel = "1.86.0"
+channel = "1.87.0"
 profile = "default"
 # The default profile includes rustc, rust-std, cargo, rust-docs, rustfmt and clippy.
 # https://rust-lang.github.io/rustup/concepts/profiles.html

storage_controller/src/scheduler.rs

@@ -628,11 +628,7 @@ impl Scheduler {
             tracing::trace!(%node_id, "attached_shard_count={} shard_count={} expected={}", node.attached_shard_count, node.shard_count, expected_attached_shards_per_node);
         }
 
-        if node.attached_shard_count < expected_attached_shards_per_node {
-            expected_attached_shards_per_node - node.attached_shard_count
-        } else {
-            0
-        }
+        expected_attached_shards_per_node.saturating_sub(node.attached_shard_count)
     }
 
     pub(crate) fn expected_attached_shard_count(&self) -> usize {