2 files changed, 1 insertions, 4 deletions
diff --git a/compiler/rustc_span/src/def_id.rs b/compiler/rustc_span/src/def_id.rs
index 595babc26ae..595456e6d6a 100644
--- a/compiler/rustc_span/src/def_id.rs
+++ b/compiler/rustc_span/src/def_id.rs
@@ -13,7 +13,6 @@ pub type StableCrateIdMap =
     indexmap::IndexMap<StableCrateId, CrateNum, BuildHasherDefault<Unhasher>>;
 
 rustc_index::newtype_index! {
-    #[custom_encodable]
     #[debug_format = "crate{}"]
     pub struct CrateNum {}
 }
@@ -213,7 +212,6 @@ rustc_index::newtype_index! {
     /// A DefIndex is an index into the hir-map for a crate, identifying a
     /// particular definition. It should really be considered an interned
     /// shorthand for a particular DefPath.
-    #[custom_encodable] // (only encodable in metadata)
     #[debug_format = "DefIndex({})"]
     pub struct DefIndex {
         /// The crate root is always assigned index 0 by the AST Map code,
@@ -222,6 +220,7 @@ rustc_index::newtype_index! {
     }
 }
 
+// njn: I don't understand these
 impl<E: Encoder> Encodable<E> for DefIndex {
     default fn encode(&self, _: &mut E) {
         panic!("cannot encode `DefIndex` with `{}`", std::any::type_name::<E>());
diff --git a/compiler/rustc_span/src/hygiene.rs b/compiler/rustc_span/src/hygiene.rs
index 988ff57254c..8c6600c4e53 100644
--- a/compiler/rustc_span/src/hygiene.rs
+++ b/compiler/rustc_span/src/hygiene.rs
@@ -60,7 +60,6 @@ pub struct SyntaxContextData {
 
 rustc_index::newtype_index! {
     /// A unique ID associated with a macro invocation and expansion.
-    #[custom_encodable]
     pub struct ExpnIndex {}
 }
 
@@ -80,7 +79,6 @@ impl fmt::Debug for ExpnId {
 
 rustc_index::newtype_index! {
     /// A unique ID associated with a macro invocation and expansion.
-    #[custom_encodable]
     #[no_ord_impl]
     #[debug_format = "expn{}"]
     pub struct LocalExpnId {}