Support x-crate default fields

3 files changed, 13 insertions, 1 deletions

diff --git a/compiler/rustc_metadata/src/rmeta/decoder.rs b/compiler/rustc_metadata/src/rmeta/decoder.rs
index 4a4930fff9d..b9586338655 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder.rs
@@ -1104,7 +1104,7 @@ impl<'a> CrateMetadataRef<'a> {
                         name: self.item_name(did.index),
                         vis: self.get_visibility(did.index),
                         safety: self.get_safety(did.index),
-                        value: None,
+                        value: self.get_default_field(did.index),
                     })
                     .collect(),
                 adt_kind,
@@ -1170,6 +1170,10 @@ impl<'a> CrateMetadataRef<'a> {
         self.root.tables.safety.get(self, id).unwrap_or_else(|| self.missing("safety", id))
     }
 
+    fn get_default_field(self, id: DefIndex) -> Option<DefId> {
+        self.root.tables.default_fields.get(self, id).map(|d| d.decode(self))
+    }
+
     fn get_trait_item_def_id(self, id: DefIndex) -> Option<DefId> {
         self.root.tables.trait_item_def_id.get(self, id).map(|d| d.decode_from_cdata(self))
     }
diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
index d4ea1276d00..5c80d24f502 100644
--- a/compiler/rustc_metadata/src/rmeta/encoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -1401,6 +1401,13 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 continue;
             }
 
+            if def_kind == DefKind::Field
+                && let hir::Node::Field(field) = tcx.hir_node_by_def_id(local_id)
+                && let Some(anon) = field.default
+            {
+                record!(self.tables.default_fields[def_id] <- anon.def_id.to_def_id());
+            }
+
             if should_encode_span(def_kind) {
                 let def_span = tcx.def_span(local_id);
                 record!(self.tables.def_span[def_id] <- def_span);
diff --git a/compiler/rustc_metadata/src/rmeta/mod.rs b/compiler/rustc_metadata/src/rmeta/mod.rs
index a5e21ab51fd..4961464833a 100644
--- a/compiler/rustc_metadata/src/rmeta/mod.rs
+++ b/compiler/rustc_metadata/src/rmeta/mod.rs
@@ -450,6 +450,7 @@ define_tables! {
     trait_def: Table<DefIndex, LazyValue<ty::TraitDef>>,
     trait_item_def_id: Table<DefIndex, RawDefId>,
     expn_that_defined: Table<DefIndex, LazyValue<ExpnId>>,
+    default_fields: Table<DefIndex, LazyValue<DefId>>,
     params_in_repr: Table<DefIndex, LazyValue<BitSet<u32>>>,
     repr_options: Table<DefIndex, LazyValue<ReprOptions>>,
     // `def_keys` and `def_path_hashes` represent a lazy version of a