diff --git a/library/proc_macro/src/bridge/client.rs b/library/proc_macro/src/bridge/client.rs
index f3582a357ec..54d92ff5767 100644
--- a/library/proc_macro/src/bridge/client.rs
+++ b/library/proc_macro/src/bridge/client.rs
@@ -254,17 +254,17 @@ macro_rules! define_client_side {
         $(impl $name {
             $(pub(crate) fn $method($($arg: $arg_ty),*) $(-> $ret_ty)* {
                 Bridge::with(|bridge| {
-                    let mut b = bridge.cached_buffer.take();
+                    let mut buf = bridge.cached_buffer.take();
 
-                    b.clear();
-                    api_tags::Method::$name(api_tags::$name::$method).encode(&mut b, &mut ());
-                    reverse_encode!(b; $($arg),*);
+                    buf.clear();
+                    api_tags::Method::$name(api_tags::$name::$method).encode(&mut buf, &mut ());
+                    reverse_encode!(buf; $($arg),*);
 
-                    b = bridge.dispatch.call(b);
+                    buf = bridge.dispatch.call(buf);
 
-                    let r = Result::<_, PanicMessage>::decode(&mut &b[..], &mut ());
+                    let r = Result::<_, PanicMessage>::decode(&mut &buf[..], &mut ());
 
-                    bridge.cached_buffer = b;
+                    bridge.cached_buffer = buf;
 
                     r.unwrap_or_else(|e| panic::resume_unwind(e.into()))
                 })
@@ -383,20 +383,20 @@ fn run_client<A: for<'a, 's> DecodeMut<'a, 's, ()>, R: Encode<()>>(
     f: impl FnOnce(A) -> R,
 ) -> Buffer {
     // The initial `cached_buffer` contains the input.
-    let mut b = bridge.cached_buffer.take();
+    let mut buf = bridge.cached_buffer.take();
 
     panic::catch_unwind(panic::AssertUnwindSafe(|| {
         bridge.enter(|| {
-            let reader = &mut &b[..];
+            let reader = &mut &buf[..];
             let input = A::decode(reader, &mut ());
 
             // Put the `cached_buffer` back in the `Bridge`, for requests.
-            Bridge::with(|bridge| bridge.cached_buffer = b.take());
+            Bridge::with(|bridge| bridge.cached_buffer = buf.take());
 
             let output = f(input);
 
             // Take the `cached_buffer` back out, for the output value.
-            b = Bridge::with(|bridge| bridge.cached_buffer.take());
+            buf = Bridge::with(|bridge| bridge.cached_buffer.take());
 
             // HACK(eddyb) Separate encoding a success value (`Ok(output)`)
             // from encoding a panic (`Err(e: PanicMessage)`) to avoid
@@ -407,16 +407,16 @@ fn run_client<A: for<'a, 's> DecodeMut<'a, 's, ()>, R: Encode<()>>(
             // this is defensively trying to avoid any accidental panicking
             // reaching the `extern "C"` (which should `abort` but might not
             // at the moment, so this is also potentially preventing UB).
-            b.clear();
-            Ok::<_, ()>(output).encode(&mut b, &mut ());
+            buf.clear();
+            Ok::<_, ()>(output).encode(&mut buf, &mut ());
         })
     }))
     .map_err(PanicMessage::from)
     .unwrap_or_else(|e| {
-        b.clear();
-        Err::<(), _>(e).encode(&mut b, &mut ());
+        buf.clear();
+        Err::<(), _>(e).encode(&mut buf, &mut ());
     });
-    b
+    buf
 }
 
 impl Client<fn(crate::TokenStream) -> crate::TokenStream> {
diff --git a/library/proc_macro/src/bridge/server.rs b/library/proc_macro/src/bridge/server.rs
index f916d482b07..b15afa32987 100644
--- a/library/proc_macro/src/bridge/server.rs
+++ b/library/proc_macro/src/bridge/server.rs
@@ -80,15 +80,15 @@ macro_rules! define_dispatcher_impl {
         pub trait DispatcherTrait {
             // HACK(eddyb) these are here to allow `Self::$name` to work below.
             $(type $name;)*
-            fn dispatch(&mut self, b: Buffer) -> Buffer;
+            fn dispatch(&mut self, buf: Buffer) -> Buffer;
         }
 
         impl<S: Server> DispatcherTrait for Dispatcher<MarkedTypes<S>> {
             $(type $name = <MarkedTypes<S> as Types>::$name;)*
-            fn dispatch(&mut self, mut b: Buffer) -> Buffer {
+            fn dispatch(&mut self, mut buf: Buffer) -> Buffer {
                 let Dispatcher { handle_store, server } = self;
 
-                let mut reader = &b[..];
+                let mut reader = &buf[..];
                 match api_tags::Method::decode(&mut reader, &mut ()) {
                     $(api_tags::Method::$name(m) => match m {
                         $(api_tags::$name::$method => {
@@ -107,12 +107,12 @@ macro_rules! define_dispatcher_impl {
                                     .map_err(PanicMessage::from)
                             };
 
-                            b.clear();
-                            r.encode(&mut b, handle_store);
+                            buf.clear();
+                            r.encode(&mut buf, handle_store);
                         })*
                     }),*
                 }
-                b
+                buf
             }
         }
     }
@@ -141,7 +141,7 @@ impl ExecutionStrategy for SameThread {
         client_data: D,
         force_show_panics: bool,
     ) -> Buffer {
-        let mut dispatch = |b| dispatcher.dispatch(b);
+        let mut dispatch = |buf| dispatcher.dispatch(buf);
 
         run_client(
             Bridge {
@@ -175,8 +175,8 @@ impl ExecutionStrategy for CrossThread1 {
         let (res_tx, res_rx) = channel();
 
         let join_handle = thread::spawn(move || {
-            let mut dispatch = |b| {
-                req_tx.send(b).unwrap();
+            let mut dispatch = |buf| {
+                req_tx.send(buf).unwrap();
                 res_rx.recv().unwrap()
             };
 
@@ -283,18 +283,18 @@ fn run_server<
     let mut dispatcher =
         Dispatcher { handle_store: HandleStore::new(handle_counters), server: MarkedTypes(server) };
 
-    let mut b = Buffer::new();
-    input.encode(&mut b, &mut dispatcher.handle_store);
+    let mut buf = Buffer::new();
+    input.encode(&mut buf, &mut dispatcher.handle_store);
 
-    b = strategy.run_bridge_and_client(
+    buf = strategy.run_bridge_and_client(
         &mut dispatcher,
-        b,
+        buf,
         run_client,
         client_data,
         force_show_panics,
     );
 
-    Result::decode(&mut &b[..], &mut dispatcher.handle_store)
+    Result::decode(&mut &buf[..], &mut dispatcher.handle_store)
 }
 
 impl client::Client<fn(crate::TokenStream) -> crate::TokenStream> {