Pass ExpnData by reference.

Author: cjgillot

Diff for: compiler/rustc_middle/src/ty/query/on_disk_cache.rs

@@ -372,7 +372,7 @@ impl<'sess> OnDiskCache<'sess> {
                 |encoder, expn_id, data, hash| -> FileEncodeResult {
                     if expn_id.krate == LOCAL_CRATE {
                         let pos = AbsoluteBytePos::new(encoder.position());
-                        encoder.encode_tagged(TAG_EXPN_DATA, &data)?;
+                        encoder.encode_tagged(TAG_EXPN_DATA, data)?;
                         expn_data.insert(hash, pos);
                     } else {
                         foreign_expn_data.insert(hash, expn_id.local_id.as_u32());

Diff for: compiler/rustc_span/src/hygiene.rs

@@ -1142,7 +1142,7 @@ impl HygieneEncodeContext {
         &self,
         encoder: &mut T,
         mut encode_ctxt: impl FnMut(&mut T, u32, &SyntaxContextData) -> Result<(), R>,
-        mut encode_expn: impl FnMut(&mut T, ExpnId, ExpnData, ExpnHash) -> Result<(), R>,
+        mut encode_expn: impl FnMut(&mut T, ExpnId, &ExpnData, ExpnHash) -> Result<(), R>,
     ) -> Result<(), R> {
         // When we serialize a `SyntaxContextData`, we may end up serializing
         // a `SyntaxContext` that we haven't seen before
@@ -1344,15 +1344,15 @@ fn for_all_ctxts_in<E, F: FnMut(u32, SyntaxContext, &SyntaxContextData) -> Resul
 
 fn for_all_expns_in<E>(
     expns: impl Iterator<Item = ExpnId>,
-    mut f: impl FnMut(ExpnId, ExpnData, ExpnHash) -> Result<(), E>,
+    mut f: impl FnMut(ExpnId, &ExpnData, ExpnHash) -> Result<(), E>,
 ) -> Result<(), E> {
     let all_data: Vec<_> = HygieneData::with(|data| {
         expns
             .map(|expn| (expn, data.expn_data(expn).clone(), data.expn_hash(expn).clone()))
             .collect()
     });
     for (expn, data, hash) in all_data.into_iter() {
-        f(expn, data, hash)?;
+        f(expn, &data, hash)?;
     }
     Ok(())
 }