Stop enabling in_band_lifetimes in rustc_data_structures

There's a conversation 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.

(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.)

Author: scottmcm

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,
 {

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,
 {

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>>;

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>>;

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)]

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];

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)
 }

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()
     }
 

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,
 {