Merge from rustc

3 files changed, 14 insertions, 8 deletions

diff --git a/compiler/rustc_data_structures/src/sorted_map.rs b/compiler/rustc_data_structures/src/sorted_map.rs
index a01a420dfbd..c002d47815b 100644
--- a/compiler/rustc_data_structures/src/sorted_map.rs
+++ b/compiler/rustc_data_structures/src/sorted_map.rs
@@ -4,7 +4,7 @@ use std::fmt::Debug;
 use std::mem;
 use std::ops::{Bound, Index, IndexMut, RangeBounds};
 
-use rustc_macros::{Decodable_Generic, Encodable_Generic};
+use rustc_macros::{Decodable_NoContext, Encodable_NoContext};
 
 use crate::stable_hasher::{HashStable, StableHasher, StableOrd};
 
@@ -20,7 +20,7 @@ pub use index_map::SortedIndexMultiMap;
 /// stores data in a more compact way. It also supports accessing contiguous
 /// ranges of elements as a slice, and slices of already sorted elements can be
 /// inserted efficiently.
-#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable_Generic, Decodable_Generic)]
+#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable_NoContext, Decodable_NoContext)]
 pub struct SortedMap<K, V> {
     data: Vec<(K, V)>,
 }
diff --git a/compiler/rustc_data_structures/src/svh.rs b/compiler/rustc_data_structures/src/svh.rs
index 391a7c9f30d..f51fcb8ed22 100644
--- a/compiler/rustc_data_structures/src/svh.rs
+++ b/compiler/rustc_data_structures/src/svh.rs
@@ -7,12 +7,12 @@
 
 use std::fmt;
 
-use rustc_macros::{Decodable_Generic, Encodable_Generic};
+use rustc_macros::{Decodable_NoContext, Encodable_NoContext};
 
 use crate::fingerprint::Fingerprint;
 use crate::stable_hasher;
 
-#[derive(Copy, Clone, PartialEq, Eq, Debug, Encodable_Generic, Decodable_Generic, Hash)]
+#[derive(Copy, Clone, PartialEq, Eq, Debug, Encodable_NoContext, Decodable_NoContext, Hash)]
 pub struct Svh {
     hash: Fingerprint,
 }
diff --git a/compiler/rustc_data_structures/src/unord.rs b/compiler/rustc_data_structures/src/unord.rs
index 34895d3efe6..baa66cd7c85 100644
--- a/compiler/rustc_data_structures/src/unord.rs
+++ b/compiler/rustc_data_structures/src/unord.rs
@@ -9,7 +9,7 @@ use std::iter::{Product, Sum};
 use std::ops::Index;
 
 use rustc_hash::{FxHashMap, FxHashSet};
-use rustc_macros::{Decodable_Generic, Encodable_Generic};
+use rustc_macros::{Decodable_NoContext, Encodable_NoContext};
 
 use crate::fingerprint::Fingerprint;
 use crate::stable_hasher::{HashStable, StableCompare, StableHasher, ToStableHashKey};
@@ -224,7 +224,7 @@ trait UnordCollection {}
 ///
 /// See [MCP 533](https://github.com/rust-lang/compiler-team/issues/533)
 /// for more information.
-#[derive(Debug, Eq, PartialEq, Clone, Encodable_Generic, Decodable_Generic)]
+#[derive(Debug, Eq, PartialEq, Clone, Encodable_NoContext, Decodable_NoContext)]
 pub struct UnordSet<V: Eq + Hash> {
     inner: FxHashSet<V>,
 }
@@ -259,6 +259,12 @@ impl<V: Eq + Hash> UnordSet<V> {
         self.inner.is_empty()
     }
 
+    /// If the set has only one element, returns it, otherwise returns `None`.
+    #[inline]
+    pub fn get_only(&self) -> Option<&V> {
+        if self.inner.len() == 1 { self.inner.iter().next() } else { None }
+    }
+
     #[inline]
     pub fn insert(&mut self, v: V) -> bool {
         self.inner.insert(v)
@@ -415,7 +421,7 @@ impl<HCX, V: Hash + Eq + HashStable<HCX>> HashStable<HCX> for UnordSet<V> {
 ///
 /// See [MCP 533](https://github.com/rust-lang/compiler-team/issues/533)
 /// for more information.
-#[derive(Debug, Eq, PartialEq, Clone, Encodable_Generic, Decodable_Generic)]
+#[derive(Debug, Eq, PartialEq, Clone, Encodable_NoContext, Decodable_NoContext)]
 pub struct UnordMap<K: Eq + Hash, V> {
     inner: FxHashMap<K, V>,
 }
@@ -639,7 +645,7 @@ impl<HCX, K: Hash + Eq + HashStable<HCX>, V: HashStable<HCX>> HashStable<HCX> fo
 ///
 /// See [MCP 533](https://github.com/rust-lang/compiler-team/issues/533)
 /// for more information.
-#[derive(Default, Debug, Eq, PartialEq, Clone, Encodable_Generic, Decodable_Generic)]
+#[derive(Default, Debug, Eq, PartialEq, Clone, Encodable_NoContext, Decodable_NoContext)]
 pub struct UnordBag<V> {
     inner: Vec<V>,
 }