Merging upstream version 1.67.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

11 files changed, 126 insertions, 179 deletions

diff --git a/compiler/rustc_data_structures/Cargo.toml b/compiler/rustc_data_structures/Cargo.toml
index 9daa21ef6..5afce15e2 100644
--- a/compiler/rustc_data_structures/Cargo.toml
+++ b/compiler/rustc_data_structures/Cargo.toml
@@ -23,9 +23,9 @@ rustc_macros = { path = "../rustc_macros" }
 rustc_serialize = { path = "../rustc_serialize" }
 smallvec = { version = "1.8.1", features = ["const_generics", "union", "may_dangle"] }
 stable_deref_trait = "1.0.0"
-stacker = "0.1.14"
+stacker = "0.1.15"
 tempfile = "3.2"
-thin-vec = "0.2.8"
+thin-vec = "0.2.9"
 tracing = "0.1"
 
 [dependencies.parking_lot]
diff --git a/compiler/rustc_data_structures/src/fingerprint.rs b/compiler/rustc_data_structures/src/fingerprint.rs
index a39178016..d98f4e43f 100644
--- a/compiler/rustc_data_structures/src/fingerprint.rs
+++ b/compiler/rustc_data_structures/src/fingerprint.rs
@@ -140,7 +140,7 @@ impl stable_hasher::StableHasherResult for Fingerprint {
     }
 }
 
-impl_stable_hash_via_hash!(Fingerprint);
+impl_stable_traits_for_trivial_type!(Fingerprint);
 
 impl<E: Encoder> Encodable<E> for Fingerprint {
     #[inline]
diff --git a/compiler/rustc_data_structures/src/functor.rs b/compiler/rustc_data_structures/src/functor.rs
index a3d3f9883..84cb417dd 100644
--- a/compiler/rustc_data_structures/src/functor.rs
+++ b/compiler/rustc_data_structures/src/functor.rs
@@ -34,43 +34,11 @@ impl<T> IdFunctor for Vec<T> {
     type Inner = T;
 
     #[inline]
-    fn try_map_id<F, E>(self, mut f: F) -> Result<Self, E>
+    fn try_map_id<F, E>(self, f: F) -> Result<Self, E>
     where
         F: FnMut(Self::Inner) -> Result<Self::Inner, E>,
     {
-        struct HoleVec<T> {
-            vec: Vec<mem::ManuallyDrop<T>>,
-            hole: Option<usize>,
-        }
-
-        impl<T> Drop for HoleVec<T> {
-            fn drop(&mut self) {
-                unsafe {
-                    for (index, slot) in self.vec.iter_mut().enumerate() {
-                        if self.hole != Some(index) {
-                            mem::ManuallyDrop::drop(slot);
-                        }
-                    }
-                }
-            }
-        }
-
-        unsafe {
-            let (ptr, length, capacity) = self.into_raw_parts();
-            let vec = Vec::from_raw_parts(ptr.cast(), length, capacity);
-            let mut hole_vec = HoleVec { vec, hole: None };
-
-            for (index, slot) in hole_vec.vec.iter_mut().enumerate() {
-                hole_vec.hole = Some(index);
-                let original = mem::ManuallyDrop::take(slot);
-                let mapped = f(original)?;
-                *slot = mem::ManuallyDrop::new(mapped);
-                hole_vec.hole = None;
-            }
-
-            mem::forget(hole_vec);
-            Ok(Vec::from_raw_parts(ptr, length, capacity))
-        }
+        self.into_iter().map(f).collect()
     }
 }
 
diff --git a/compiler/rustc_data_structures/src/intern.rs b/compiler/rustc_data_structures/src/intern.rs
index 009b5d534..ba94f3776 100644
--- a/compiler/rustc_data_structures/src/intern.rs
+++ b/compiler/rustc_data_structures/src/intern.rs
@@ -4,8 +4,6 @@ use std::hash::{Hash, Hasher};
 use std::ops::Deref;
 use std::ptr;
 
-use crate::fingerprint::Fingerprint;
-
 mod private {
     #[derive(Clone, Copy, Debug)]
     pub struct PrivateZst;
@@ -72,7 +70,7 @@ impl<'a, T: PartialOrd> PartialOrd for Interned<'a, T> {
         if ptr::eq(self.0, other.0) {
             Some(Ordering::Equal)
         } else {
-            let res = self.0.partial_cmp(&other.0);
+            let res = self.0.partial_cmp(other.0);
             debug_assert_ne!(res, Some(Ordering::Equal));
             res
         }
@@ -86,7 +84,7 @@ impl<'a, T: Ord> Ord for Interned<'a, T> {
         if ptr::eq(self.0, other.0) {
             Ordering::Equal
         } else {
-            let res = self.0.cmp(&other.0);
+            let res = self.0.cmp(other.0);
             debug_assert_ne!(res, Ordering::Equal);
             res
         }
@@ -110,87 +108,5 @@ where
     }
 }
 
-/// A helper trait so that `Interned` things can cache stable hashes reproducibly.
-pub trait InternedHashingContext {
-    fn with_def_path_and_no_spans(&mut self, f: impl FnOnce(&mut Self));
-}
-
-/// A helper type that you can wrap round your own type in order to automatically
-/// cache the stable hash on creation and not recompute it whenever the stable hash
-/// of the type is computed.
-/// This is only done in incremental mode. You can also opt out of caching by using
-/// StableHash::ZERO for the hash, in which case the hash gets computed each time.
-/// This is useful if you have values that you intern but never (can?) use for stable
-/// hashing.
-#[derive(Copy, Clone)]
-pub struct WithStableHash<T> {
-    pub internee: T,
-    pub stable_hash: Fingerprint,
-}
-
-impl<T: PartialEq> PartialEq for WithStableHash<T> {
-    #[inline]
-    fn eq(&self, other: &Self) -> bool {
-        self.internee.eq(&other.internee)
-    }
-}
-
-impl<T: Eq> Eq for WithStableHash<T> {}
-
-impl<T: Ord> PartialOrd for WithStableHash<T> {
-    fn partial_cmp(&self, other: &WithStableHash<T>) -> Option<Ordering> {
-        Some(self.internee.cmp(&other.internee))
-    }
-}
-
-impl<T: Ord> Ord for WithStableHash<T> {
-    fn cmp(&self, other: &WithStableHash<T>) -> Ordering {
-        self.internee.cmp(&other.internee)
-    }
-}
-
-impl<T> Deref for WithStableHash<T> {
-    type Target = T;
-
-    #[inline]
-    fn deref(&self) -> &T {
-        &self.internee
-    }
-}
-
-impl<T: Hash> Hash for WithStableHash<T> {
-    #[inline]
-    fn hash<H: Hasher>(&self, s: &mut H) {
-        self.internee.hash(s)
-    }
-}
-
-impl<T: HashStable<CTX>, CTX: InternedHashingContext> HashStable<CTX> for WithStableHash<T> {
-    fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
-        if self.stable_hash == Fingerprint::ZERO || cfg!(debug_assertions) {
-            // No cached hash available. This can only mean that incremental is disabled.
-            // We don't cache stable hashes in non-incremental mode, because they are used
-            // so rarely that the performance actually suffers.
-
-            // We need to build the hash as if we cached it and then hash that hash, as
-            // otherwise the hashes will differ between cached and non-cached mode.
-            let stable_hash: Fingerprint = {
-                let mut hasher = StableHasher::new();
-                hcx.with_def_path_and_no_spans(|hcx| self.internee.hash_stable(hcx, &mut hasher));
-                hasher.finish()
-            };
-            if cfg!(debug_assertions) && self.stable_hash != Fingerprint::ZERO {
-                assert_eq!(
-                    stable_hash, self.stable_hash,
-                    "cached stable hash does not match freshly computed stable hash"
-                );
-            }
-            stable_hash.hash_stable(hcx, hasher);
-        } else {
-            self.stable_hash.hash_stable(hcx, hasher);
-        }
-    }
-}
-
 #[cfg(test)]
 mod tests;
diff --git a/compiler/rustc_data_structures/src/memmap.rs b/compiler/rustc_data_structures/src/memmap.rs
index 917416df6..3d44e17f3 100644
--- a/compiler/rustc_data_structures/src/memmap.rs
+++ b/compiler/rustc_data_structures/src/memmap.rs
@@ -36,6 +36,12 @@ impl Deref for Mmap {
 
     #[inline]
     fn deref(&self) -> &[u8] {
+        &self.0
+    }
+}
+
+impl AsRef<[u8]> for Mmap {
+    fn as_ref(&self) -> &[u8] {
         &*self.0
     }
 }
@@ -96,13 +102,13 @@ impl Deref for MmapMut {
 
     #[inline]
     fn deref(&self) -> &[u8] {
-        &*self.0
+        &self.0
     }
 }
 
 impl DerefMut for MmapMut {
     #[inline]
     fn deref_mut(&mut self) -> &mut [u8] {
-        &mut *self.0
+        &mut self.0
     }
 }
diff --git a/compiler/rustc_data_structures/src/owning_ref/mod.rs b/compiler/rustc_data_structures/src/owning_ref/mod.rs
index ed5e56618..980a540cc 100644
--- a/compiler/rustc_data_structures/src/owning_ref/mod.rs
+++ b/compiler/rustc_data_structures/src/owning_ref/mod.rs
@@ -899,25 +899,25 @@ unsafe impl<O, T: ?Sized> StableAddress for OwningRef<O, T> {}
 
 impl<O, T: ?Sized> AsRef<T> for OwningRef<O, T> {
     fn as_ref(&self) -> &T {
-        &*self
+        self
     }
 }
 
 impl<O, T: ?Sized> AsRef<T> for OwningRefMut<O, T> {
     fn as_ref(&self) -> &T {
-        &*self
+        self
     }
 }
 
 impl<O, T: ?Sized> AsMut<T> for OwningRefMut<O, T> {
     fn as_mut(&mut self) -> &mut T {
-        &mut *self
+        self
     }
 }
 
 impl<O, T: ?Sized> Borrow<T> for OwningRef<O, T> {
     fn borrow(&self) -> &T {
-        &*self
+        self
     }
 }
 
@@ -1021,7 +1021,7 @@ where
     T: PartialEq,
 {
     fn eq(&self, other: &Self) -> bool {
-        (&*self as &T).eq(&*other as &T)
+        self.deref().eq(other.deref())
     }
 }
 
@@ -1032,7 +1032,7 @@ where
     T: PartialOrd,
 {
     fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        (&*self as &T).partial_cmp(&*other as &T)
+        self.deref().partial_cmp(other.deref())
     }
 }
 
@@ -1041,7 +1041,7 @@ where
     T: Ord,
 {
     fn cmp(&self, other: &Self) -> Ordering {
-        (&*self as &T).cmp(&*other as &T)
+        self.deref().cmp(other.deref())
     }
 }
 
@@ -1050,7 +1050,7 @@ where
     T: Hash,
 {
     fn hash<H: Hasher>(&self, state: &mut H) {
-        (&*self as &T).hash(state);
+        self.deref().hash(state);
     }
 }
 
@@ -1059,7 +1059,7 @@ where
     T: PartialEq,
 {
     fn eq(&self, other: &Self) -> bool {
-        (&*self as &T).eq(&*other as &T)
+        self.deref().eq(other.deref())
     }
 }
 
@@ -1070,7 +1070,7 @@ where
     T: PartialOrd,
 {
     fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        (&*self as &T).partial_cmp(&*other as &T)
+        self.deref().partial_cmp(other.deref())
     }
 }
 
@@ -1079,7 +1079,7 @@ where
     T: Ord,
 {
     fn cmp(&self, other: &Self) -> Ordering {
-        (&*self as &T).cmp(&*other as &T)
+        self.deref().cmp(other.deref())
     }
 }
 
@@ -1088,7 +1088,7 @@ where
     T: Hash,
 {
     fn hash<H: Hasher>(&self, state: &mut H) {
-        (&*self as &T).hash(state);
+        self.deref().hash(state);
     }
 }
 
diff --git a/compiler/rustc_data_structures/src/profiling.rs b/compiler/rustc_data_structures/src/profiling.rs
index ba1960805..aa7a01eed 100644
--- a/compiler/rustc_data_structures/src/profiling.rs
+++ b/compiler/rustc_data_structures/src/profiling.rs
@@ -192,7 +192,7 @@ impl SelfProfilerRef {
             F: for<'a> FnOnce(&'a SelfProfiler) -> TimingGuard<'a>,
         {
             let profiler = profiler_ref.profiler.as_ref().unwrap();
-            f(&**profiler)
+            f(profiler)
         }
 
         if self.event_filter_mask.contains(event_filter) {
@@ -466,7 +466,7 @@ impl SelfProfilerRef {
 
     pub fn with_profiler(&self, f: impl FnOnce(&SelfProfiler)) {
         if let Some(profiler) = &self.profiler {
-            f(&profiler)
+            f(profiler)
         }
     }
 
@@ -733,7 +733,7 @@ impl Drop for VerboseTimingGuard<'_> {
         if let Some((start_time, start_rss, ref message)) = self.start_and_message {
             let end_rss = get_resident_set_size();
             let dur = start_time.elapsed();
-            print_time_passes_entry(&message, dur, start_rss, end_rss);
+            print_time_passes_entry(message, dur, start_rss, end_rss);
         }
     }
 }
diff --git a/compiler/rustc_data_structures/src/sorted_map.rs b/compiler/rustc_data_structures/src/sorted_map.rs
index fe257e102..d13313dfd 100644
--- a/compiler/rustc_data_structures/src/sorted_map.rs
+++ b/compiler/rustc_data_structures/src/sorted_map.rs
@@ -1,4 +1,4 @@
-use crate::stable_hasher::{HashStable, StableHasher};
+use crate::stable_hasher::{HashStable, StableHasher, StableOrd};
 use std::borrow::Borrow;
 use std::cmp::Ordering;
 use std::iter::FromIterator;
@@ -10,8 +10,8 @@ mod index_map;
 pub use index_map::SortedIndexMultiMap;
 
 /// `SortedMap` is a data structure with similar characteristics as BTreeMap but
-/// slightly different trade-offs: lookup, insertion, and removal are *O*(log(*n*))
-/// and elements can be iterated in order cheaply.
+/// slightly different trade-offs: lookup is *O*(log(*n*)), insertion and removal
+/// are *O*(*n*) but elements can be iterated in order cheaply.
 ///
 /// `SortedMap` can be faster than a `BTreeMap` for small sizes (<50) since it
 /// stores data in a more compact way. It also supports accessing contiguous
@@ -308,7 +308,7 @@ impl<K: Ord, V> FromIterator<(K, V)> for SortedMap<K, V> {
     }
 }
 
-impl<K: HashStable<CTX>, V: HashStable<CTX>, CTX> HashStable<CTX> for SortedMap<K, V> {
+impl<K: HashStable<CTX> + StableOrd, V: HashStable<CTX>, CTX> HashStable<CTX> for SortedMap<K, V> {
     #[inline]
     fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
         self.data.hash_stable(ctx, hasher);
diff --git a/compiler/rustc_data_structures/src/sorted_map/index_map.rs b/compiler/rustc_data_structures/src/sorted_map/index_map.rs
index 0ec32dc43..c2f0ae328 100644
--- a/compiler/rustc_data_structures/src/sorted_map/index_map.rs
+++ b/compiler/rustc_data_structures/src/sorted_map/index_map.rs
@@ -120,13 +120,20 @@ where
         self.items.hash(hasher)
     }
 }
+
 impl<I: Idx, K, V, C> HashStable<C> for SortedIndexMultiMap<I, K, V>
 where
     K: HashStable<C>,
     V: HashStable<C>,
 {
     fn hash_stable(&self, ctx: &mut C, hasher: &mut StableHasher) {
-        self.items.hash_stable(ctx, hasher)
+        let SortedIndexMultiMap {
+            items,
+            // We can ignore this field because it is not observable from the outside.
+            idx_sorted_by_item_key: _,
+        } = self;
+
+        items.hash_stable(ctx, hasher)
     }
 }
 
diff --git a/compiler/rustc_data_structures/src/stable_hasher.rs b/compiler/rustc_data_structures/src/stable_hasher.rs
index ce8591734..1a728f82f 100644
--- a/compiler/rustc_data_structures/src/stable_hasher.rs
+++ b/compiler/rustc_data_structures/src/stable_hasher.rs
@@ -219,7 +219,35 @@ pub trait ToStableHashKey<HCX> {
     fn to_stable_hash_key(&self, hcx: &HCX) -> Self::KeyType;
 }
 
-/// Implement HashStable by just calling `Hash::hash()`.
+/// Trait for marking a type as having a sort order that is
+/// stable across compilation session boundaries. More formally:
+///
+/// ```txt
+/// Ord::cmp(a1, b1) == Ord:cmp(a2, b2)
+///    where a2 = decode(encode(a1, context1), context2)
+///          b2 = decode(encode(b1, context1), context2)
+/// ```
+///
+/// i.e. the result of `Ord::cmp` is not influenced by encoding
+/// the values in one session and then decoding them in another
+/// session.
+///
+/// This is trivially true for types where encoding and decoding
+/// don't change the bytes of the values that are used during
+/// comparison and comparison only depends on these bytes (as
+/// opposed to some non-local state). Examples are u32, String,
+/// Path, etc.
+///
+/// But it is not true for:
+///  - `*const T` and `*mut T` because the values of these pointers
+///    will change between sessions.
+///  - `DefIndex`, `CrateNum`, `LocalDefId`, because their concrete
+///    values depend on state that might be different between
+///    compilation sessions.
+pub unsafe trait StableOrd: Ord {}
+
+/// Implement HashStable by just calling `Hash::hash()`. Also implement `StableOrd` for the type since
+/// that has the same requirements.
 ///
 /// **WARNING** This is only valid for types that *really* don't need any context for fingerprinting.
 /// But it is easy to misuse this macro (see [#96013](https://github.com/rust-lang/rust/issues/96013)
@@ -227,7 +255,7 @@ pub trait ToStableHashKey<HCX> {
 /// here in this module.
 ///
 /// Use `#[derive(HashStable_Generic)]` instead.
-macro_rules! impl_stable_hash_via_hash {
+macro_rules! impl_stable_traits_for_trivial_type {
     ($t:ty) => {
         impl<CTX> $crate::stable_hasher::HashStable<CTX> for $t {
             #[inline]
@@ -235,26 +263,28 @@ macro_rules! impl_stable_hash_via_hash {
                 ::std::hash::Hash::hash(self, hasher);
             }
         }
+
+        unsafe impl $crate::stable_hasher::StableOrd for $t {}
     };
 }
 
-impl_stable_hash_via_hash!(i8);
-impl_stable_hash_via_hash!(i16);
-impl_stable_hash_via_hash!(i32);
-impl_stable_hash_via_hash!(i64);
-impl_stable_hash_via_hash!(isize);
+impl_stable_traits_for_trivial_type!(i8);
+impl_stable_traits_for_trivial_type!(i16);
+impl_stable_traits_for_trivial_type!(i32);
+impl_stable_traits_for_trivial_type!(i64);
+impl_stable_traits_for_trivial_type!(isize);
 
-impl_stable_hash_via_hash!(u8);
-impl_stable_hash_via_hash!(u16);
-impl_stable_hash_via_hash!(u32);
-impl_stable_hash_via_hash!(u64);
-impl_stable_hash_via_hash!(usize);
+impl_stable_traits_for_trivial_type!(u8);
+impl_stable_traits_for_trivial_type!(u16);
+impl_stable_traits_for_trivial_type!(u32);
+impl_stable_traits_for_trivial_type!(u64);
+impl_stable_traits_for_trivial_type!(usize);
 
-impl_stable_hash_via_hash!(u128);
-impl_stable_hash_via_hash!(i128);
+impl_stable_traits_for_trivial_type!(u128);
+impl_stable_traits_for_trivial_type!(i128);
 
-impl_stable_hash_via_hash!(char);
-impl_stable_hash_via_hash!(());
+impl_stable_traits_for_trivial_type!(char);
+impl_stable_traits_for_trivial_type!(());
 
 impl<CTX> HashStable<CTX> for ! {
     fn hash_stable(&self, _ctx: &mut CTX, _hasher: &mut StableHasher) {
@@ -366,7 +396,7 @@ impl<CTX> HashStable<CTX> for [u8] {
 impl<T: HashStable<CTX>, CTX> HashStable<CTX> for Vec<T> {
     #[inline]
     fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
-        (&self[..]).hash_stable(ctx, hasher);
+        self[..].hash_stable(ctx, hasher);
     }
 }
 
@@ -399,13 +429,13 @@ where
     }
 }
 
-impl<A, CTX> HashStable<CTX> for SmallVec<[A; 1]>
+impl<A, const N: usize, CTX> HashStable<CTX> for SmallVec<[A; N]>
 where
     A: HashStable<CTX>,
 {
     #[inline]
     fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
-        (&self[..]).hash_stable(ctx, hasher);
+        self[..].hash_stable(ctx, hasher);
     }
 }
 
@@ -440,10 +470,14 @@ impl<CTX> HashStable<CTX> for str {
 impl<CTX> HashStable<CTX> for String {
     #[inline]
     fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
-        (&self[..]).hash_stable(hcx, hasher);
+        self[..].hash_stable(hcx, hasher);
     }
 }
 
+// Safety: String comparison only depends on their contents and the
+// contents are not changed by (de-)serialization.
+unsafe impl StableOrd for String {}
+
 impl<HCX> ToStableHashKey<HCX> for String {
     type KeyType = String;
     #[inline]
@@ -459,6 +493,9 @@ impl<CTX> HashStable<CTX> for bool {
     }
 }
 
+// Safety: sort order of bools is not changed by (de-)serialization.
+unsafe impl StableOrd for bool {}
+
 impl<T, CTX> HashStable<CTX> for Option<T>
 where
     T: HashStable<CTX>,
@@ -474,6 +511,9 @@ where
     }
 }
 
+// Safety: the Option wrapper does not add instability to comparison.
+unsafe impl<T: StableOrd> StableOrd for Option<T> {}
+
 impl<T1, T2, CTX> HashStable<CTX> for Result<T1, T2>
 where
     T1: HashStable<CTX>,
@@ -550,8 +590,8 @@ where
     }
 }
 
-impl_stable_hash_via_hash!(::std::path::Path);
-impl_stable_hash_via_hash!(::std::path::PathBuf);
+impl_stable_traits_for_trivial_type!(::std::path::Path);
+impl_stable_traits_for_trivial_type!(::std::path::PathBuf);
 
 impl<K, V, R, HCX> HashStable<HCX> for ::std::collections::HashMap<K, V, R>
 where
@@ -584,27 +624,26 @@ where
 
 impl<K, V, HCX> HashStable<HCX> for ::std::collections::BTreeMap<K, V>
 where
-    K: ToStableHashKey<HCX>,
+    K: HashStable<HCX> + StableOrd,
     V: HashStable<HCX>,
 {
     fn hash_stable(&self, hcx: &mut HCX, hasher: &mut StableHasher) {
-        stable_hash_reduce(hcx, hasher, self.iter(), self.len(), |hasher, hcx, (key, value)| {
-            let key = key.to_stable_hash_key(hcx);
-            key.hash_stable(hcx, hasher);
-            value.hash_stable(hcx, hasher);
-        });
+        self.len().hash_stable(hcx, hasher);
+        for entry in self.iter() {
+            entry.hash_stable(hcx, hasher);
+        }
     }
 }
 
 impl<K, HCX> HashStable<HCX> for ::std::collections::BTreeSet<K>
 where
-    K: ToStableHashKey<HCX>,
+    K: HashStable<HCX> + StableOrd,
 {
     fn hash_stable(&self, hcx: &mut HCX, hasher: &mut StableHasher) {
-        stable_hash_reduce(hcx, hasher, self.iter(), self.len(), |hasher, hcx, key| {
-            let key = key.to_stable_hash_key(hcx);
-            key.hash_stable(hcx, hasher);
-        });
+        self.len().hash_stable(hcx, hasher);
+        for entry in self.iter() {
+            entry.hash_stable(hcx, hasher);
+        }
     }
 }
 
diff --git a/compiler/rustc_data_structures/src/sync.rs b/compiler/rustc_data_structures/src/sync.rs
index 9c0fb8265..e4f47b22a 100644
--- a/compiler/rustc_data_structures/src/sync.rs
+++ b/compiler/rustc_data_structures/src/sync.rs
@@ -201,7 +201,7 @@ cfg_if! {
 
             #[inline(always)]
             fn deref(&self) -> &T {
-                &*self.0
+                &self.0
             }
         }
 
@@ -410,6 +410,7 @@ impl<T> Lock<T> {
 
     #[cfg(parallel_compiler)]
     #[inline(always)]
+    #[track_caller]
     pub fn lock(&self) -> LockGuard<'_, T> {
         if ERROR_CHECKING {
             self.0.try_lock().expect("lock was already held")
@@ -420,21 +421,25 @@ impl<T> Lock<T> {
 
     #[cfg(not(parallel_compiler))]
     #[inline(always)]
+    #[track_caller]
     pub fn lock(&self) -> LockGuard<'_, T> {
         self.0.borrow_mut()
     }
 
     #[inline(always)]
+    #[track_caller]
     pub fn with_lock<F: FnOnce(&mut T) -> R, R>(&self, f: F) -> R {
         f(&mut *self.lock())
     }
 
     #[inline(always)]
+    #[track_caller]
     pub fn borrow(&self) -> LockGuard<'_, T> {
         self.lock()
     }
 
     #[inline(always)]
+    #[track_caller]
     pub fn borrow_mut(&self) -> LockGuard<'_, T> {
         self.lock()
     }
@@ -476,6 +481,7 @@ impl<T> RwLock<T> {
 
     #[cfg(not(parallel_compiler))]
     #[inline(always)]
+    #[track_caller]
     pub fn read(&self) -> ReadGuard<'_, T> {
         self.0.borrow()
     }
@@ -491,6 +497,7 @@ impl<T> RwLock<T> {
     }
 
     #[inline(always)]
+    #[track_caller]
     pub fn with_read_lock<F: FnOnce(&T) -> R, R>(&self, f: F) -> R {
         f(&*self.read())
     }
@@ -509,6 +516,7 @@ impl<T> RwLock<T> {
 
     #[cfg(not(parallel_compiler))]
     #[inline(always)]
+    #[track_caller]
     pub fn write(&self) -> WriteGuard<'_, T> {
         self.0.borrow_mut()
     }
@@ -524,16 +532,19 @@ impl<T> RwLock<T> {
     }
 
     #[inline(always)]
+    #[track_caller]
     pub fn with_write_lock<F: FnOnce(&mut T) -> R, R>(&self, f: F) -> R {
         f(&mut *self.write())
     }
 
     #[inline(always)]
+    #[track_caller]
     pub fn borrow(&self) -> ReadGuard<'_, T> {
         self.read()
     }
 
     #[inline(always)]
+    #[track_caller]
     pub fn borrow_mut(&self) -> WriteGuard<'_, T> {
         self.write()
     }