Auto merge of #75137 - Aaron1011:fix/hygiene-skip-expndata, r=petrochenkov

[rust.git] / src / librustc_metadata / rmeta / encoder.rs

diff --git a/src/librustc_metadata/rmeta/encoder.rs b/src/librustc_metadata/rmeta/encoder.rs
index 3f92226e5480d879c46b4b0396023f514bea8e07..f75f0b74a0e1e19eed3290bd55e477826e1e6f50 100644 (file)
--- a/src/librustc_metadata/rmeta/encoder.rs
+++ b/src/librustc_metadata/rmeta/encoder.rs
@@ -279,6 +279,10 @@ fn specialized_encode(&mut self, span: &Span) -> Result<(), Self::Error> {
         // cross-crate inconsistencies (getting one behavior in the same
         // crate, and a different behavior in another crate) due to the
         // limited surface that proc-macros can expose.
+        //
+        // IMPORTANT: If this is ever changed, be sure to update
+        // `rustc_span::hygiene::raw_encode_expn_id` to handle
+        // encoding `ExpnData` for proc-macro crates.
         if self.is_proc_macro {
             SyntaxContext::root().encode(self)?;
         } else {