1 files changed, 22 insertions, 7 deletions
diff --git a/compiler/rustc_hir/src/hir_id.rs b/compiler/rustc_hir/src/hir_id.rs
index 060f40919..404abe2b0 100644
--- a/compiler/rustc_hir/src/hir_id.rs
+++ b/compiler/rustc_hir/src/hir_id.rs
@@ -1,14 +1,21 @@
 use crate::def_id::{DefId, DefIndex, LocalDefId, CRATE_DEF_ID};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, StableOrd, ToStableHashKey};
 use rustc_span::{def_id::DefPathHash, HashStableContext};
-use std::fmt;
+use std::fmt::{self, Debug};
 
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash)]
 #[derive(Encodable, Decodable)]
 pub struct OwnerId {
     pub def_id: LocalDefId,
 }
 
+impl Debug for OwnerId {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // Example: DefId(0:1 ~ aa[7697]::{use#0})
+        Debug::fmt(&self.def_id, f)
+    }
+}
+
 impl From<OwnerId> for HirId {
     fn from(owner: OwnerId) -> HirId {
         HirId { owner, local_id: ItemLocalId::from_u32(0) }
@@ -60,7 +67,7 @@ impl<CTX: HashStableContext> ToStableHashKey<CTX> for OwnerId {
 /// the `local_id` part of the `HirId` changing, which is a very useful property in
 /// incremental compilation where we have to persist things through changes to
 /// the code base.
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash)]
 #[derive(Encodable, Decodable, HashStable_Generic)]
 #[rustc_pass_by_value]
 pub struct HirId {
@@ -68,6 +75,14 @@ pub struct HirId {
     pub local_id: ItemLocalId,
 }
 
+impl Debug for HirId {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // Example: HirId(DefId(0:1 ~ aa[7697]::{use#0}).10)
+        // Don't use debug_tuple to always keep this on one line.
+        write!(f, "HirId({:?}.{:?})", self.owner, self.local_id)
+    }
+}
+
 impl HirId {
     /// Signal local id which should never be used.
     pub const INVALID: HirId =
@@ -104,7 +119,7 @@ impl HirId {
 
 impl fmt::Display for HirId {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{:?}", self)
+        write!(f, "{self:?}")
     }
 }
 
@@ -133,12 +148,12 @@ rustc_index::newtype_index! {
     /// that is, within a `hir::Item`, `hir::TraitItem`, or `hir::ImplItem`. There is no
     /// guarantee that the numerical value of a given `ItemLocalId` corresponds to
     /// the node's position within the owning item in any way, but there is a
-    /// guarantee that the `LocalItemId`s within an owner occupy a dense range of
+    /// guarantee that the `ItemLocalId`s within an owner occupy a dense range of
     /// integers starting at zero, so a mapping that maps all or most nodes within
     /// an "item-like" to something else can be implemented by a `Vec` instead of a
     /// tree or hash map.
     #[derive(HashStable_Generic)]
-    pub struct ItemLocalId { .. }
+    pub struct ItemLocalId {}
 }
 
 impl ItemLocalId {
@@ -146,7 +161,7 @@ impl ItemLocalId {
     pub const INVALID: ItemLocalId = ItemLocalId::MAX;
 }
 
-// Safety: Ord is implement as just comparing the LocalItemId's numerical
+// Safety: Ord is implement as just comparing the ItemLocalId's numerical
 // values and these are not changed by (de-)serialization.
 unsafe impl StableOrd for ItemLocalId {}