Auto merge of #91580 - scottmcm:less-inband-1-of-28, r=petrochenkov

Stop enabling `in_band_lifetimes` in rustc_data_structures

There's a conversation started in the tracking issue about possibly unaccepting `in_band_lifetimes`, but it's used heavily in the compiler, and thus there'd need to be a bunch of PRs like this if that were to happen.

So here's one to see how much of an impact it has.  For this crate, at least, it doesn't seem like in-band was a big win -- about half the places that were using it didn't even need a named lifetime.

(Oh, and I removed `nll` while I was here too, since it didn't seem needed.  Let me know if I should put that back.)

r? `@petrochenkov`

9 files changed, 13 insertions, 15 deletions

diff --git a/compiler/rustc_data_structures/src/binary_search_util/mod.rs b/compiler/rustc_data_structures/src/binary_search_util/mod.rs
index ede5757a479..bf09b2f8eef 100644
--- a/compiler/rustc_data_structures/src/binary_search_util/mod.rs
+++ b/compiler/rustc_data_structures/src/binary_search_util/mod.rs
@@ -6,7 +6,7 @@ mod tests;
 /// function finds the range of elements that match the key. `data`
 /// must have been sorted as if by a call to `sort_by_key` for this to
 /// work.
-pub fn binary_search_slice<E, K>(data: &'d [E], key_fn: impl Fn(&E) -> K, key: &K) -> &'d [E]
+pub fn binary_search_slice<'d, E, K>(data: &'d [E], key_fn: impl Fn(&E) -> K, key: &K) -> &'d [E]
 where
     K: Ord,
 {
diff --git a/compiler/rustc_data_structures/src/graph/iterate/mod.rs b/compiler/rustc_data_structures/src/graph/iterate/mod.rs
index a9db3497b23..57007611a76 100644
--- a/compiler/rustc_data_structures/src/graph/iterate/mod.rs
+++ b/compiler/rustc_data_structures/src/graph/iterate/mod.rs
@@ -79,7 +79,7 @@ where
     visited: BitSet<G::Node>,
 }
 
-impl<G> DepthFirstSearch<'graph, G>
+impl<'graph, G> DepthFirstSearch<'graph, G>
 where
     G: ?Sized + DirectedGraph + WithNumNodes + WithSuccessors,
 {
@@ -209,7 +209,7 @@ where
     settled: BitSet<G::Node>,
 }
 
-impl<G> TriColorDepthFirstSearch<'graph, G>
+impl<'graph, G> TriColorDepthFirstSearch<'graph, G>
 where
     G: ?Sized + DirectedGraph + WithNumNodes + WithSuccessors,
 {
@@ -276,7 +276,7 @@ where
     }
 }
 
-impl<G> TriColorDepthFirstSearch<'graph, G>
+impl<G> TriColorDepthFirstSearch<'_, G>
 where
     G: ?Sized + DirectedGraph + WithNumNodes + WithSuccessors + WithStartNode,
 {
diff --git a/compiler/rustc_data_structures/src/graph/scc/mod.rs b/compiler/rustc_data_structures/src/graph/scc/mod.rs
index b84f28b6a9e..508a084b311 100644
--- a/compiler/rustc_data_structures/src/graph/scc/mod.rs
+++ b/compiler/rustc_data_structures/src/graph/scc/mod.rs
@@ -97,7 +97,7 @@ impl<N: Idx, S: Idx> WithNumEdges for Sccs<N, S> {
     }
 }
 
-impl<N: Idx, S: Idx> GraphSuccessors<'graph> for Sccs<N, S> {
+impl<'graph, N: Idx, S: Idx> GraphSuccessors<'graph> for Sccs<N, S> {
     type Item = S;
 
     type Iter = std::iter::Cloned<std::slice::Iter<'graph, S>>;
diff --git a/compiler/rustc_data_structures/src/graph/vec_graph/mod.rs b/compiler/rustc_data_structures/src/graph/vec_graph/mod.rs
index 4ed88878418..5d9bc1b2e51 100644
--- a/compiler/rustc_data_structures/src/graph/vec_graph/mod.rs
+++ b/compiler/rustc_data_structures/src/graph/vec_graph/mod.rs
@@ -94,7 +94,7 @@ impl<N: Idx> WithNumEdges for VecGraph<N> {
     }
 }
 
-impl<N: Idx> GraphSuccessors<'graph> for VecGraph<N> {
+impl<'graph, N: Idx> GraphSuccessors<'graph> for VecGraph<N> {
     type Item = N;
 
     type Iter = std::iter::Cloned<std::slice::Iter<'graph, N>>;
diff --git a/compiler/rustc_data_structures/src/lib.rs b/compiler/rustc_data_structures/src/lib.rs
index 77784bf1705..e17724b72f8 100644
--- a/compiler/rustc_data_structures/src/lib.rs
+++ b/compiler/rustc_data_structures/src/lib.rs
@@ -15,13 +15,11 @@
 #![feature(core_intrinsics)]
 #![feature(extend_one)]
 #![feature(hash_raw_entry)]
-#![feature(in_band_lifetimes)]
 #![feature(maybe_uninit_uninit_array)]
 #![feature(min_specialization)]
 #![feature(never_type)]
 #![feature(type_alias_impl_trait)]
 #![feature(new_uninit)]
-#![feature(nll)]
 #![feature(once_cell)]
 #![feature(test)]
 #![feature(thread_id_value)]
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 61c7239c55f..593316e2699 100644
--- a/compiler/rustc_data_structures/src/sorted_map/index_map.rs
+++ b/compiler/rustc_data_structures/src/sorted_map/index_map.rs
@@ -84,7 +84,7 @@ impl<I: Idx, K: Ord, V> SortedIndexMultiMap<I, K, V> {
     /// If there are multiple items that are equivalent to `key`, they will be yielded in
     /// insertion order.
     #[inline]
-    pub fn get_by_key(&'a self, key: K) -> impl 'a + Iterator<Item = &'a V> {
+    pub fn get_by_key(&self, key: K) -> impl Iterator<Item = &V> + '_ {
         self.get_by_key_enumerated(key).map(|(_, v)| v)
     }
 
@@ -94,7 +94,7 @@ impl<I: Idx, K: Ord, V> SortedIndexMultiMap<I, K, V> {
     /// If there are multiple items that are equivalent to `key`, they will be yielded in
     /// insertion order.
     #[inline]
-    pub fn get_by_key_enumerated(&'a self, key: K) -> impl '_ + Iterator<Item = (I, &V)> {
+    pub fn get_by_key_enumerated(&self, key: K) -> impl Iterator<Item = (I, &V)> + '_ {
         let lower_bound = self.idx_sorted_by_item_key.partition_point(|&i| self.items[i].0 < key);
         self.idx_sorted_by_item_key[lower_bound..].iter().map_while(move |&i| {
             let (k, v) = &self.items[i];
diff --git a/compiler/rustc_data_structures/src/sso/map.rs b/compiler/rustc_data_structures/src/sso/map.rs
index 2de05cd4e56..ec6a62016a8 100644
--- a/compiler/rustc_data_structures/src/sso/map.rs
+++ b/compiler/rustc_data_structures/src/sso/map.rs
@@ -423,14 +423,14 @@ impl<K, V> IntoIterator for SsoHashMap<K, V> {
 
 /// adapts Item of array reference iterator to Item of hashmap reference iterator.
 #[inline(always)]
-fn adapt_array_ref_it<K, V>(pair: &'a (K, V)) -> (&'a K, &'a V) {
+fn adapt_array_ref_it<K, V>(pair: &(K, V)) -> (&K, &V) {
     let (a, b) = pair;
     (a, b)
 }
 
 /// adapts Item of array mut reference iterator to Item of hashmap mut reference iterator.
 #[inline(always)]
-fn adapt_array_mut_it<K, V>(pair: &'a mut (K, V)) -> (&'a K, &'a mut V) {
+fn adapt_array_mut_it<K, V>(pair: &mut (K, V)) -> (&K, &mut V) {
     let (a, b) = pair;
     (a, b)
 }
diff --git a/compiler/rustc_data_structures/src/sso/set.rs b/compiler/rustc_data_structures/src/sso/set.rs
index 29baf4e1ddb..f71522d3714 100644
--- a/compiler/rustc_data_structures/src/sso/set.rs
+++ b/compiler/rustc_data_structures/src/sso/set.rs
@@ -75,7 +75,7 @@ impl<T> SsoHashSet<T> {
     /// An iterator visiting all elements in arbitrary order.
     /// The iterator element type is `&'a T`.
     #[inline]
-    pub fn iter(&'a self) -> impl Iterator<Item = &'a T> {
+    pub fn iter(&self) -> impl Iterator<Item = &T> {
         self.into_iter()
     }
 
diff --git a/compiler/rustc_data_structures/src/vec_linked_list.rs b/compiler/rustc_data_structures/src/vec_linked_list.rs
index 1cf030d852e..ce60d40b24b 100644
--- a/compiler/rustc_data_structures/src/vec_linked_list.rs
+++ b/compiler/rustc_data_structures/src/vec_linked_list.rs
@@ -2,8 +2,8 @@ use rustc_index::vec::{Idx, IndexVec};
 
 pub fn iter<Ls>(
     first: Option<Ls::LinkIndex>,
-    links: &'a Ls,
-) -> impl Iterator<Item = Ls::LinkIndex> + 'a
+    links: &Ls,
+) -> impl Iterator<Item = Ls::LinkIndex> + '_
 where
     Ls: Links,
 {