Fix up comment about OnDiskCache::foreign_expn_data.

rust-lang · Sep 14, 2021 · 021c052 · 021c052
1 parent 2b60338
commit 021c052
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/compiler/rustc_query_impl/src/on_disk_cache.rs b/compiler/rustc_query_impl/src/on_disk_cache.rs
@@ -86,8 +86,10 @@ pub struct OnDiskCache<'sess> {
     expn_data: UnhashMap<ExpnHash, AbsoluteBytePos>,
     // Additional information used when decoding hygiene data.
     hygiene_context: HygieneDecodeContext,
-    // FIXME(mw): Update this comment:
-    // Likewise for ExpnId.
+    // Maps `ExpnHash`es to their raw value from the *previous*
+    // compilation session. This is used as an initial 'guess' when
+    // we try to map an `ExpnHash` to its value in the current
+    // compilation session.
     foreign_expn_data: UnhashMap<ExpnHash, u32>,
 }