diff --git a/.gitattributes b/.gitattributes
index 4038db6f7dab1..d29c15fe712f3 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -7,11 +7,11 @@
 *.fixed linguist-language=Rust
 *.mir linguist-language=Rust
 src/etc/installer/gfx/* binary
-*.woff binary
-*.woff2 binary
 src/vendor/** -text
 Cargo.lock linguist-generated=false
 
-# Older git versions try to fix line endings on images, this prevents it.
+# Older git versions try to fix line endings on images and fonts, this prevents it.
 *.png binary
 *.ico binary
+*.woff binary
+*.woff2 binary
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 99a0c0b4b85de..2ead68638fa4a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -622,7 +622,7 @@ jobs:
     if: "github.event_name == 'push' && github.ref == 'refs/heads/master' && github.repository == 'rust-lang-ci/rust'"
     steps:
       - name: checkout the source code
-        uses: actions/checkout@v1
+        uses: actions/checkout@v2
         with:
           fetch-depth: 2
       - name: publish toolstate
diff --git a/Cargo.lock b/Cargo.lock
index fd6fffe980bc5..d970c1a355515 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1895,9 +1895,9 @@ checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"
 
 [[package]]
 name = "libc"
-version = "0.2.88"
+version = "0.2.89"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "03b07a082330a35e43f63177cc01689da34fbffa0105e1246cf0311472cac73a"
+checksum = "538c092e5586f4cdd7dd8078c4a79220e3e168880218124dcbce860f0ea938c6"
 dependencies = [
  "rustc-std-workspace-core",
 ]
diff --git a/compiler/rustc_arena/src/lib.rs b/compiler/rustc_arena/src/lib.rs
index a9917f50cc202..c3198fb10431c 100644
--- a/compiler/rustc_arena/src/lib.rs
+++ b/compiler/rustc_arena/src/lib.rs
@@ -298,22 +298,6 @@ impl<T> TypedArena<T> {
         }
     }
 
-    /// Clears the arena. Deallocates all but the longest chunk which may be reused.
-    pub fn clear(&mut self) {
-        unsafe {
-            // Clear the last chunk, which is partially filled.
-            let mut chunks_borrow = self.chunks.borrow_mut();
-            if let Some(mut last_chunk) = chunks_borrow.last_mut() {
-                self.clear_last_chunk(&mut last_chunk);
-                let len = chunks_borrow.len();
-                // If `T` is ZST, code below has no effect.
-                for mut chunk in chunks_borrow.drain(..len - 1) {
-                    chunk.destroy(chunk.entries);
-                }
-            }
-        }
-    }
-
     // Drops the contents of the last chunk. The last chunk is partially empty, unlike all other
     // chunks.
     fn clear_last_chunk(&self, last_chunk: &mut TypedArenaChunk<T>) {
diff --git a/compiler/rustc_arena/src/tests.rs b/compiler/rustc_arena/src/tests.rs
index e8a1f2db1a16b..911e577c1edc7 100644
--- a/compiler/rustc_arena/src/tests.rs
+++ b/compiler/rustc_arena/src/tests.rs
@@ -11,6 +11,24 @@ struct Point {
     z: i32,
 }
 
+impl<T> TypedArena<T> {
+    /// Clears the arena. Deallocates all but the longest chunk which may be reused.
+    fn clear(&mut self) {
+        unsafe {
+            // Clear the last chunk, which is partially filled.
+            let mut chunks_borrow = self.chunks.borrow_mut();
+            if let Some(mut last_chunk) = chunks_borrow.last_mut() {
+                self.clear_last_chunk(&mut last_chunk);
+                let len = chunks_borrow.len();
+                // If `T` is ZST, code below has no effect.
+                for mut chunk in chunks_borrow.drain(..len - 1) {
+                    chunk.destroy(chunk.entries);
+                }
+            }
+        }
+    }
+}
+
 #[test]
 pub fn test_unused() {
     let arena: TypedArena<Point> = TypedArena::default();
diff --git a/compiler/rustc_codegen_ssa/src/lib.rs b/compiler/rustc_codegen_ssa/src/lib.rs
index 2c2330409fd70..dd04d3e548f8c 100644
--- a/compiler/rustc_codegen_ssa/src/lib.rs
+++ b/compiler/rustc_codegen_ssa/src/lib.rs
@@ -1,6 +1,6 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
+#![feature(assert_matches)]
 #![feature(bool_to_option)]
-#![feature(option_expect_none)]
 #![feature(box_patterns)]
 #![feature(drain_filter)]
 #![feature(try_blocks)]
diff --git a/compiler/rustc_data_structures/src/tiny_list.rs b/compiler/rustc_data_structures/src/tiny_list.rs
index e94a0c6eb5943..f88bcc2948150 100644
--- a/compiler/rustc_data_structures/src/tiny_list.rs
+++ b/compiler/rustc_data_structures/src/tiny_list.rs
@@ -15,7 +15,7 @@
 mod tests;
 
 #[derive(Clone)]
-pub struct TinyList<T: PartialEq> {
+pub struct TinyList<T> {
     head: Option<Element<T>>,
 }
 
@@ -56,20 +56,10 @@ impl<T: PartialEq> TinyList<T> {
         }
         false
     }
-
-    #[inline]
-    pub fn len(&self) -> usize {
-        let (mut elem, mut count) = (self.head.as_ref(), 0);
-        while let Some(ref e) = elem {
-            count += 1;
-            elem = e.next.as_deref();
-        }
-        count
-    }
 }
 
 #[derive(Clone)]
-struct Element<T: PartialEq> {
+struct Element<T> {
     data: T,
     next: Option<Box<Element<T>>>,
 }
diff --git a/compiler/rustc_data_structures/src/tiny_list/tests.rs b/compiler/rustc_data_structures/src/tiny_list/tests.rs
index a8ae2bc872789..c0334d2e23e55 100644
--- a/compiler/rustc_data_structures/src/tiny_list/tests.rs
+++ b/compiler/rustc_data_structures/src/tiny_list/tests.rs
@@ -3,6 +3,17 @@ use super::*;
 extern crate test;
 use test::{black_box, Bencher};
 
+impl<T> TinyList<T> {
+    fn len(&self) -> usize {
+        let (mut elem, mut count) = (self.head.as_ref(), 0);
+        while let Some(ref e) = elem {
+            count += 1;
+            elem = e.next.as_deref();
+        }
+        count
+    }
+}
+
 #[test]
 fn test_contains_and_insert() {
     fn do_insert(i: u32) -> bool {
diff --git a/compiler/rustc_data_structures/src/transitive_relation.rs b/compiler/rustc_data_structures/src/transitive_relation.rs
index 2e1512b3929ca..ccf8bd69ebd06 100644
--- a/compiler/rustc_data_structures/src/transitive_relation.rs
+++ b/compiler/rustc_data_structures/src/transitive_relation.rs
@@ -9,7 +9,7 @@ use std::mem;
 mod tests;
 
 #[derive(Clone, Debug)]
-pub struct TransitiveRelation<T: Eq + Hash> {
+pub struct TransitiveRelation<T> {
     // List of elements. This is used to map from a T to a usize.
     elements: FxIndexSet<T>,
 
@@ -49,7 +49,7 @@ struct Edge {
     target: Index,
 }
 
-impl<T: Clone + Debug + Eq + Hash> TransitiveRelation<T> {
+impl<T: Eq + Hash> TransitiveRelation<T> {
     pub fn is_empty(&self) -> bool {
         self.edges.is_empty()
     }
@@ -322,12 +322,6 @@ impl<T: Clone + Debug + Eq + Hash> TransitiveRelation<T> {
             .collect()
     }
 
-    /// A "best" parent in some sense. See `parents` and
-    /// `postdom_upper_bound` for more details.
-    pub fn postdom_parent(&self, a: &T) -> Option<&T> {
-        self.mutual_immediate_postdominator(self.parents(a))
-    }
-
     fn with_closure<OP, R>(&self, op: OP) -> R
     where
         OP: FnOnce(&BitMatrix<usize, usize>) -> R,
diff --git a/compiler/rustc_data_structures/src/transitive_relation/tests.rs b/compiler/rustc_data_structures/src/transitive_relation/tests.rs
index ca90ba176ae1a..9fa7224376c1c 100644
--- a/compiler/rustc_data_structures/src/transitive_relation/tests.rs
+++ b/compiler/rustc_data_structures/src/transitive_relation/tests.rs
@@ -1,5 +1,13 @@
 use super::*;
 
+impl<T: Eq + Hash> TransitiveRelation<T> {
+    /// A "best" parent in some sense. See `parents` and
+    /// `postdom_upper_bound` for more details.
+    fn postdom_parent(&self, a: &T) -> Option<&T> {
+        self.mutual_immediate_postdominator(self.parents(a))
+    }
+}
+
 #[test]
 fn test_one_step() {
     let mut relation = TransitiveRelation::default();
diff --git a/compiler/rustc_expand/src/proc_macro_server.rs b/compiler/rustc_expand/src/proc_macro_server.rs
index 67edfe19da383..cb41bc81225ec 100644
--- a/compiler/rustc_expand/src/proc_macro_server.rs
+++ b/compiler/rustc_expand/src/proc_macro_server.rs
@@ -53,11 +53,11 @@ impl ToInternal<token::DelimToken> for Delimiter {
     }
 }
 
-impl FromInternal<(TreeAndSpacing, &'_ ParseSess, &'_ mut Vec<Self>)>
+impl FromInternal<(TreeAndSpacing, &'_ mut Vec<Self>, &mut Rustc<'_>)>
     for TokenTree<Group, Punct, Ident, Literal>
 {
     fn from_internal(
-        ((tree, spacing), sess, stack): (TreeAndSpacing, &ParseSess, &mut Vec<Self>),
+        ((tree, spacing), stack, rustc): (TreeAndSpacing, &mut Vec<Self>, &mut Rustc<'_>),
     ) -> Self {
         use rustc_ast::token::*;
 
@@ -146,10 +146,10 @@ impl FromInternal<(TreeAndSpacing, &'_ ParseSess, &'_ mut Vec<Self>)>
             SingleQuote => op!('\''),
 
             Ident(name, false) if name == kw::DollarCrate => tt!(Ident::dollar_crate()),
-            Ident(name, is_raw) => tt!(Ident::new(sess, name, is_raw)),
+            Ident(name, is_raw) => tt!(Ident::new(rustc.sess, name, is_raw)),
             Lifetime(name) => {
                 let ident = symbol::Ident::new(name, span).without_first_quote();
-                stack.push(tt!(Ident::new(sess, ident.name, false)));
+                stack.push(tt!(Ident::new(rustc.sess, ident.name, false)));
                 tt!(Punct::new('\'', true))
             }
             Literal(lit) => tt!(Literal { lit }),
@@ -179,15 +179,15 @@ impl FromInternal<(TreeAndSpacing, &'_ ParseSess, &'_ mut Vec<Self>)>
             }
 
             Interpolated(nt) => {
-                if let Some((name, is_raw)) = ident_name_compatibility_hack(&nt, span, sess) {
-                    TokenTree::Ident(Ident::new(sess, name.name, is_raw, name.span))
+                if let Some((name, is_raw)) = ident_name_compatibility_hack(&nt, span, rustc) {
+                    TokenTree::Ident(Ident::new(rustc.sess, name.name, is_raw, name.span))
                 } else {
-                    let stream = nt_to_tokenstream(&nt, sess, CanSynthesizeMissingTokens::No);
+                    let stream = nt_to_tokenstream(&nt, rustc.sess, CanSynthesizeMissingTokens::No);
                     TokenTree::Group(Group {
                         delimiter: Delimiter::None,
                         stream,
                         span: DelimSpan::from_single(span),
-                        flatten: crate::base::pretty_printing_compatibility_hack(&nt, sess),
+                        flatten: crate::base::pretty_printing_compatibility_hack(&nt, rustc.sess),
                     })
                 }
             }
@@ -449,7 +449,7 @@ impl server::TokenStreamIter for Rustc<'_> {
         loop {
             let tree = iter.stack.pop().or_else(|| {
                 let next = iter.cursor.next_with_spacing()?;
-                Some(TokenTree::from_internal((next, self.sess, &mut iter.stack)))
+                Some(TokenTree::from_internal((next, &mut iter.stack, self)))
             })?;
             // A hack used to pass AST fragments to attribute and derive macros
             // as a single nonterminal token instead of a token stream.
@@ -719,11 +719,11 @@ impl server::Span for Rustc<'_> {
 fn ident_name_compatibility_hack(
     nt: &Nonterminal,
     orig_span: Span,
-    sess: &ParseSess,
+    rustc: &mut Rustc<'_>,
 ) -> Option<(rustc_span::symbol::Ident, bool)> {
     if let NtIdent(ident, is_raw) = nt {
         if let ExpnKind::Macro(_, macro_name) = orig_span.ctxt().outer_expn_data().kind {
-            let source_map = sess.source_map();
+            let source_map = rustc.sess.source_map();
             let filename = source_map.span_to_filename(orig_span);
             if let FileName::Real(RealFileName::Named(path)) = filename {
                 let matches_prefix = |prefix, filename| {
@@ -745,7 +745,7 @@ fn ident_name_compatibility_hack(
                     let snippet = source_map.span_to_snippet(orig_span);
                     if snippet.as_deref() == Ok("$name") {
                         if time_macros_impl {
-                            sess.buffer_lint_with_diagnostic(
+                            rustc.sess.buffer_lint_with_diagnostic(
                                 &PROC_MACRO_BACK_COMPAT,
                                 orig_span,
                                 ast::CRATE_NODE_ID,
@@ -759,13 +759,25 @@ fn ident_name_compatibility_hack(
                     }
                 }
 
-                if macro_name == sym::tuple_from_req
-                    && (matches_prefix("actix-web", "extract.rs")
-                        || matches_prefix("actori-web", "extract.rs"))
-                {
+                if macro_name == sym::tuple_from_req && matches_prefix("actix-web", "extract.rs") {
                     let snippet = source_map.span_to_snippet(orig_span);
                     if snippet.as_deref() == Ok("$T") {
-                        return Some((*ident, *is_raw));
+                        if let FileName::Real(RealFileName::Named(macro_path)) =
+                            source_map.span_to_filename(rustc.def_site)
+                        {
+                            if macro_path.to_string_lossy().contains("pin-project-internal-0.") {
+                                rustc.sess.buffer_lint_with_diagnostic(
+                                    &PROC_MACRO_BACK_COMPAT,
+                                    orig_span,
+                                    ast::CRATE_NODE_ID,
+                                    "using an old version of `actix-web`",
+                                    BuiltinLintDiagnostics::ProcMacroBackCompat(
+                                    "the version of `actix-web` you are using might stop compiling in future versions of Rust; \
+                                    please update to the latest version of the `actix-web` crate to avoid breakage".to_string())
+                                );
+                                return Some((*ident, *is_raw));
+                            }
+                        }
                     }
                 }
             }
diff --git a/compiler/rustc_middle/src/ich/impls_syntax.rs b/compiler/rustc_middle/src/ich/impls_syntax.rs
index bfbe15749ee1c..31374429940ca 100644
--- a/compiler/rustc_middle/src/ich/impls_syntax.rs
+++ b/compiler/rustc_middle/src/ich/impls_syntax.rs
@@ -45,7 +45,11 @@ impl<'ctx> rustc_ast::HashStableContext for StableHashingContext<'ctx> {
             item.hash_stable(self, hasher);
             style.hash_stable(self, hasher);
             span.hash_stable(self, hasher);
-            tokens.as_ref().expect_none("Tokens should have been removed during lowering!");
+            assert_matches!(
+                tokens.as_ref(),
+                None,
+                "Tokens should have been removed during lowering!"
+            );
         } else {
             unreachable!();
         }
diff --git a/compiler/rustc_middle/src/lib.rs b/compiler/rustc_middle/src/lib.rs
index d9e8826505002..2d807591bfdd2 100644
--- a/compiler/rustc_middle/src/lib.rs
+++ b/compiler/rustc_middle/src/lib.rs
@@ -24,6 +24,7 @@
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(array_windows)]
+#![feature(assert_matches)]
 #![feature(assoc_char_funcs)]
 #![feature(backtrace)]
 #![feature(bool_to_option)]
@@ -38,7 +39,6 @@
 #![feature(extern_types)]
 #![feature(nll)]
 #![feature(once_cell)]
-#![feature(option_expect_none)]
 #![feature(or_patterns)]
 #![feature(min_specialization)]
 #![feature(trusted_len)]
diff --git a/compiler/rustc_middle/src/mir/interpret/allocation.rs b/compiler/rustc_middle/src/mir/interpret/allocation.rs
index 48595f2badc8f..766d6a06f7e59 100644
--- a/compiler/rustc_middle/src/mir/interpret/allocation.rs
+++ b/compiler/rustc_middle/src/mir/interpret/allocation.rs
@@ -339,7 +339,7 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
         for dest in bytes {
             *dest = src.next().expect("iterator was shorter than it said it would be");
         }
-        src.next().expect_none("iterator was longer than it said it would be");
+        assert_matches!(src.next(), None, "iterator was longer than it said it would be");
         Ok(())
     }
 
diff --git a/compiler/rustc_mir/src/interpret/memory.rs b/compiler/rustc_mir/src/interpret/memory.rs
index f3e373813ca53..fe5ebf0b6fe97 100644
--- a/compiler/rustc_mir/src/interpret/memory.rs
+++ b/compiler/rustc_mir/src/interpret/memory.rs
@@ -854,7 +854,11 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
             Some(ptr) => ptr,
             None => {
                 // zero-sized access
-                src.next().expect_none("iterator said it was empty but returned an element");
+                assert_matches!(
+                    src.next(),
+                    None,
+                    "iterator said it was empty but returned an element"
+                );
                 return Ok(());
             }
         };
@@ -880,7 +884,11 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
             Some(ptr) => ptr,
             None => {
                 // zero-sized access
-                src.next().expect_none("iterator said it was empty but returned an element");
+                assert_matches!(
+                    src.next(),
+                    None,
+                    "iterator said it was empty but returned an element"
+                );
                 return Ok(());
             }
         };
@@ -894,7 +902,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
             let offset_ptr = ptr.offset(Size::from_bytes(idx) * 2, &tcx)?; // `Size` multiplication
             allocation.write_scalar(&tcx, offset_ptr, val.into(), Size::from_bytes(2))?;
         }
-        src.next().expect_none("iterator was longer than it said it would be");
+        assert_matches!(src.next(), None, "iterator was longer than it said it would be");
         Ok(())
     }
 
diff --git a/compiler/rustc_mir/src/lib.rs b/compiler/rustc_mir/src/lib.rs
index 194bc74c0fb1a..f73d5dc0c116d 100644
--- a/compiler/rustc_mir/src/lib.rs
+++ b/compiler/rustc_mir/src/lib.rs
@@ -7,6 +7,7 @@ Rust MIR: a lowered representation of Rust.
 #![feature(nll)]
 #![feature(in_band_lifetimes)]
 #![feature(array_windows)]
+#![feature(assert_matches)]
 #![feature(bindings_after_at)]
 #![feature(bool_to_option)]
 #![feature(box_patterns)]
@@ -18,13 +19,13 @@ Rust MIR: a lowered representation of Rust.
 #![feature(exact_size_is_empty)]
 #![feature(exhaustive_patterns)]
 #![feature(never_type)]
+#![feature(map_try_insert)]
 #![feature(min_specialization)]
 #![feature(trusted_len)]
 #![feature(try_blocks)]
 #![feature(associated_type_defaults)]
 #![feature(stmt_expr_attributes)]
 #![feature(trait_alias)]
-#![feature(option_expect_none)]
 #![feature(option_get_or_insert_default)]
 #![feature(or_patterns)]
 #![feature(once_cell)]
diff --git a/compiler/rustc_mir/src/transform/coverage/debug.rs b/compiler/rustc_mir/src/transform/coverage/debug.rs
index 2cd0dc6b1f2fd..aabfee53acb29 100644
--- a/compiler/rustc_mir/src/transform/coverage/debug.rs
+++ b/compiler/rustc_mir/src/transform/coverage/debug.rs
@@ -285,10 +285,8 @@ impl DebugCounters {
                 ),
             };
             counters
-                .insert(id, DebugCounter::new(counter_kind.clone(), some_block_label))
-                .expect_none(
-                    "attempt to add the same counter_kind to DebugCounters more than once",
-                );
+                .try_insert(id, DebugCounter::new(counter_kind.clone(), some_block_label))
+                .expect("attempt to add the same counter_kind to DebugCounters more than once");
         }
     }
 
@@ -479,9 +477,9 @@ impl GraphvizData {
         counter_kind: &CoverageKind,
     ) {
         if let Some(edge_to_counter) = self.some_edge_to_counter.as_mut() {
-            edge_to_counter.insert((from_bcb, to_bb), counter_kind.clone()).expect_none(
-                "invalid attempt to insert more than one edge counter for the same edge",
-            );
+            edge_to_counter
+                .try_insert((from_bcb, to_bb), counter_kind.clone())
+                .expect("invalid attempt to insert more than one edge counter for the same edge");
         }
     }
 
diff --git a/compiler/rustc_mir/src/transform/deduplicate_blocks.rs b/compiler/rustc_mir/src/transform/deduplicate_blocks.rs
index c4b51099f5389..e102512e1f37f 100644
--- a/compiler/rustc_mir/src/transform/deduplicate_blocks.rs
+++ b/compiler/rustc_mir/src/transform/deduplicate_blocks.rs
@@ -86,7 +86,7 @@ fn find_duplicates<'a, 'tcx>(body: &'a Body<'tcx>) -> FxHashMap<BasicBlock, Basi
                 // The basic block was already in the hashmap, which means we have a duplicate
                 let value = *occupied.get();
                 debug!("Inserting {:?} -> {:?}", bb, value);
-                duplicates.insert(bb, value).expect_none("key was already inserted");
+                duplicates.try_insert(bb, value).expect("key was already inserted");
             }
             Entry::Vacant(vacant) => {
                 vacant.insert(bb);
diff --git a/compiler/rustc_span/src/hygiene.rs b/compiler/rustc_span/src/hygiene.rs
index e67a4ca8fb26b..eb5b7c4a74a1d 100644
--- a/compiler/rustc_span/src/hygiene.rs
+++ b/compiler/rustc_span/src/hygiene.rs
@@ -118,7 +118,8 @@ impl ExpnId {
         HygieneData::with(|data| {
             let old_expn_data = &mut data.expn_data[self.0 as usize];
             assert!(old_expn_data.is_none(), "expansion data is reset for an expansion ID");
-            expn_data.orig_id.replace(self.as_u32()).expect_none("orig_id should be None");
+            assert_eq!(expn_data.orig_id, None);
+            expn_data.orig_id = Some(self.as_u32());
             *old_expn_data = Some(expn_data);
         });
         update_disambiguator(self)
@@ -202,7 +203,8 @@ impl HygieneData {
     fn fresh_expn(&mut self, mut expn_data: Option<ExpnData>) -> ExpnId {
         let raw_id = self.expn_data.len() as u32;
         if let Some(data) = expn_data.as_mut() {
-            data.orig_id.replace(raw_id).expect_none("orig_id should be None");
+            assert_eq!(data.orig_id, None);
+            data.orig_id = Some(raw_id);
         }
         self.expn_data.push(expn_data);
         ExpnId(raw_id)
@@ -1410,9 +1412,11 @@ fn update_disambiguator(expn_id: ExpnId) {
             let new_hash: Fingerprint = hasher.finish();
 
             HygieneData::with(|data| {
-                data.expn_data_disambiguators
-                    .get(&new_hash)
-                    .expect_none("Hash collision after disambiguator update!");
+                assert_eq!(
+                    data.expn_data_disambiguators.get(&new_hash),
+                    None,
+                    "Hash collision after disambiguator update!",
+                );
             });
         };
     }
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index 6030c8a86d9f9..d2790335b5abc 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -21,7 +21,6 @@
 #![feature(negative_impls)]
 #![feature(nll)]
 #![feature(min_specialization)]
-#![feature(option_expect_none)]
 
 #[macro_use]
 extern crate rustc_macros;
@@ -1996,7 +1995,8 @@ impl<CTX: HashStableContext> HashStable<CTX> for ExpnId {
                 if cache.len() < new_len {
                     cache.resize(new_len, None);
                 }
-                cache[index].replace(sub_hash).expect_none("Cache slot was filled");
+                let prev = cache[index].replace(sub_hash);
+                assert_eq!(prev, None, "Cache slot was filled");
             });
             sub_hash.hash_stable(ctx, hasher);
         }
diff --git a/compiler/rustc_span/src/source_map.rs b/compiler/rustc_span/src/source_map.rs
index b7eb6d5b3790b..f612d1425b932 100644
--- a/compiler/rustc_span/src/source_map.rs
+++ b/compiler/rustc_span/src/source_map.rs
@@ -453,41 +453,6 @@ impl SourceMap {
         }
     }
 
-    /// Returns `Some(span)`, a union of the LHS and RHS span. The LHS must precede the RHS. If
-    /// there are gaps between LHS and RHS, the resulting union will cross these gaps.
-    /// For this to work,
-    ///
-    ///    * the syntax contexts of both spans much match,
-    ///    * the LHS span needs to end on the same line the RHS span begins,
-    ///    * the LHS span must start at or before the RHS span.
-    pub fn merge_spans(&self, sp_lhs: Span, sp_rhs: Span) -> Option<Span> {
-        // Ensure we're at the same expansion ID.
-        if sp_lhs.ctxt() != sp_rhs.ctxt() {
-            return None;
-        }
-
-        let lhs_end = match self.lookup_line(sp_lhs.hi()) {
-            Ok(x) => x,
-            Err(_) => return None,
-        };
-        let rhs_begin = match self.lookup_line(sp_rhs.lo()) {
-            Ok(x) => x,
-            Err(_) => return None,
-        };
-
-        // If we must cross lines to merge, don't merge.
-        if lhs_end.line != rhs_begin.line {
-            return None;
-        }
-
-        // Ensure these follow the expected order and that we don't overlap.
-        if (sp_lhs.lo() <= sp_rhs.lo()) && (sp_lhs.hi() <= sp_rhs.lo()) {
-            Some(sp_lhs.to(sp_rhs))
-        } else {
-            None
-        }
-    }
-
     pub fn span_to_string(&self, sp: Span) -> String {
         if self.files.borrow().source_files.is_empty() && sp.is_dummy() {
             return "no-location".to_string();
@@ -931,13 +896,6 @@ impl SourceMap {
         SourceFileAndBytePos { sf, pos: offset }
     }
 
-    /// Converts an absolute `BytePos` to a `CharPos` relative to the `SourceFile`.
-    pub fn bytepos_to_file_charpos(&self, bpos: BytePos) -> CharPos {
-        let idx = self.lookup_source_file_idx(bpos);
-        let sf = &(*self.files.borrow().source_files)[idx];
-        sf.bytepos_to_file_charpos(bpos)
-    }
-
     // Returns the index of the `SourceFile` (in `self.files`) that contains `pos`.
     // This index is guaranteed to be valid for the lifetime of this `SourceMap`,
     // since `source_files` is a `MonotonicVec`
diff --git a/compiler/rustc_span/src/source_map/tests.rs b/compiler/rustc_span/src/source_map/tests.rs
index 0aca677248b72..7d814f1d82c11 100644
--- a/compiler/rustc_span/src/source_map/tests.rs
+++ b/compiler/rustc_span/src/source_map/tests.rs
@@ -10,6 +10,50 @@ fn init_source_map() -> SourceMap {
     sm
 }
 
+impl SourceMap {
+    /// Returns `Some(span)`, a union of the LHS and RHS span. The LHS must precede the RHS. If
+    /// there are gaps between LHS and RHS, the resulting union will cross these gaps.
+    /// For this to work,
+    ///
+    ///    * the syntax contexts of both spans much match,
+    ///    * the LHS span needs to end on the same line the RHS span begins,
+    ///    * the LHS span must start at or before the RHS span.
+    fn merge_spans(&self, sp_lhs: Span, sp_rhs: Span) -> Option<Span> {
+        // Ensure we're at the same expansion ID.
+        if sp_lhs.ctxt() != sp_rhs.ctxt() {
+            return None;
+        }
+
+        let lhs_end = match self.lookup_line(sp_lhs.hi()) {
+            Ok(x) => x,
+            Err(_) => return None,
+        };
+        let rhs_begin = match self.lookup_line(sp_rhs.lo()) {
+            Ok(x) => x,
+            Err(_) => return None,
+        };
+
+        // If we must cross lines to merge, don't merge.
+        if lhs_end.line != rhs_begin.line {
+            return None;
+        }
+
+        // Ensure these follow the expected order and that we don't overlap.
+        if (sp_lhs.lo() <= sp_rhs.lo()) && (sp_lhs.hi() <= sp_rhs.lo()) {
+            Some(sp_lhs.to(sp_rhs))
+        } else {
+            None
+        }
+    }
+
+    /// Converts an absolute `BytePos` to a `CharPos` relative to the `SourceFile`.
+    fn bytepos_to_file_charpos(&self, bpos: BytePos) -> CharPos {
+        let idx = self.lookup_source_file_idx(bpos);
+        let sf = &(*self.files.borrow().source_files)[idx];
+        sf.bytepos_to_file_charpos(bpos)
+    }
+}
+
 /// Tests `lookup_byte_offset`.
 #[test]
 fn t3() {
diff --git a/library/alloc/Cargo.toml b/library/alloc/Cargo.toml
index d95b5b7f17f42..4f97c95bcb9ea 100644
--- a/library/alloc/Cargo.toml
+++ b/library/alloc/Cargo.toml
@@ -2,6 +2,9 @@
 authors = ["The Rust Project Developers"]
 name = "alloc"
 version = "0.0.0"
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/rust-lang/rust.git"
+description = "The Rust core allocation and collections library"
 autotests = false
 autobenches = false
 edition = "2018"
diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs
index e2e705d7980ca..019b17a594536 100644
--- a/library/alloc/src/string.rs
+++ b/library/alloc/src/string.rs
@@ -1202,6 +1202,62 @@ impl String {
         ch
     }
 
+    /// Remove all matches of pattern `pat` in the `String`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(string_remove_matches)]
+    /// let mut s = String::from("Trees are not green, the sky is not blue.");
+    /// s.remove_matches("not ");
+    /// assert_eq!("Trees are green, the sky is blue.", s);
+    /// ```
+    ///
+    /// Matches will be detected and removed iteratively, so in cases where
+    /// patterns overlap, only the first pattern will be removed:
+    ///
+    /// ```
+    /// #![feature(string_remove_matches)]
+    /// let mut s = String::from("banana");
+    /// s.remove_matches("ana");
+    /// assert_eq!("bna", s);
+    /// ```
+    #[unstable(feature = "string_remove_matches", reason = "new API", issue = "72826")]
+    pub fn remove_matches<'a, P>(&'a mut self, pat: P)
+    where
+        P: for<'x> Pattern<'x>,
+    {
+        use core::str::pattern::Searcher;
+
+        let matches = {
+            let mut searcher = pat.into_searcher(self);
+            let mut matches = Vec::new();
+
+            while let Some(m) = searcher.next_match() {
+                matches.push(m);
+            }
+
+            matches
+        };
+
+        let len = self.len();
+        let mut shrunk_by = 0;
+
+        // SAFETY: start and end will be on utf8 byte boundaries per
+        // the Searcher docs
+        unsafe {
+            for (start, end) in matches {
+                ptr::copy(
+                    self.vec.as_mut_ptr().add(end - shrunk_by),
+                    self.vec.as_mut_ptr().add(start - shrunk_by),
+                    len - end,
+                );
+                shrunk_by += end - start;
+            }
+            self.vec.set_len(len - shrunk_by);
+        }
+    }
+
     /// Retains only the characters specified by the predicate.
     ///
     /// In other words, remove all characters `c` such that `f(c)` returns `false`.
diff --git a/library/alloc/tests/lib.rs b/library/alloc/tests/lib.rs
index 11673ed8262bd..06874bff44ed6 100644
--- a/library/alloc/tests/lib.rs
+++ b/library/alloc/tests/lib.rs
@@ -22,6 +22,7 @@
 #![feature(slice_partition_dedup)]
 #![feature(vec_extend_from_within)]
 #![feature(vec_spare_capacity)]
+#![feature(string_remove_matches)]
 
 use std::collections::hash_map::DefaultHasher;
 use std::hash::{Hash, Hasher};
diff --git a/library/alloc/tests/string.rs b/library/alloc/tests/string.rs
index f3d74e0514d29..9ec0ee97ab926 100644
--- a/library/alloc/tests/string.rs
+++ b/library/alloc/tests/string.rs
@@ -365,6 +365,33 @@ fn remove_bad() {
     "ศ".to_string().remove(1);
 }
 
+#[test]
+fn test_remove_matches() {
+    let mut s = "abc".to_string();
+
+    s.remove_matches('b');
+    assert_eq!(s, "ac");
+    s.remove_matches('b');
+    assert_eq!(s, "ac");
+
+    let mut s = "abcb".to_string();
+
+    s.remove_matches('b');
+    assert_eq!(s, "ac");
+
+    let mut s = "ศไทย中华Việt Nam; foobarศ".to_string();
+    s.remove_matches('ศ');
+    assert_eq!(s, "ไทย中华Việt Nam; foobar");
+
+    let mut s = "".to_string();
+    s.remove_matches("");
+    assert_eq!(s, "");
+
+    let mut s = "aaaaa".to_string();
+    s.remove_matches('a');
+    assert_eq!(s, "");
+}
+
 #[test]
 fn test_retain() {
     let mut s = String::from("α_β_γ");
diff --git a/library/core/Cargo.toml b/library/core/Cargo.toml
index c1596012eac24..4a7dbb91822e2 100644
--- a/library/core/Cargo.toml
+++ b/library/core/Cargo.toml
@@ -2,6 +2,9 @@
 authors = ["The Rust Project Developers"]
 name = "core"
 version = "0.0.0"
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/rust-lang/rust.git"
+description = "The Rust Core Library"
 autotests = false
 autobenches = false
 edition = "2018"
diff --git a/library/core/src/iter/traits/iterator.rs b/library/core/src/iter/traits/iterator.rs
index f8504e842ee33..a07750f4ad1fe 100644
--- a/library/core/src/iter/traits/iterator.rs
+++ b/library/core/src/iter/traits/iterator.rs
@@ -1012,7 +1012,7 @@ pub trait Iterator {
     ///
     /// Because the closure passed to `skip_while()` takes a reference, and many
     /// iterators iterate over references, this leads to a possibly confusing
-    /// situation, where the type of the closure is a double reference:
+    /// situation, where the type of the closure argument is a double reference:
     ///
     /// ```
     /// let a = [-1, 0, 1];
diff --git a/library/panic_abort/Cargo.toml b/library/panic_abort/Cargo.toml
index b15919fad75e7..caa89aa30d0bb 100644
--- a/library/panic_abort/Cargo.toml
+++ b/library/panic_abort/Cargo.toml
@@ -2,6 +2,9 @@
 authors = ["The Rust Project Developers"]
 name = "panic_abort"
 version = "0.0.0"
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/rust-lang/rust.git"
+description = "Implementation of Rust panics via process aborts"
 edition = "2018"
 
 [lib]
diff --git a/library/panic_unwind/Cargo.toml b/library/panic_unwind/Cargo.toml
index d27ba9876416d..533f059a85e45 100644
--- a/library/panic_unwind/Cargo.toml
+++ b/library/panic_unwind/Cargo.toml
@@ -2,6 +2,9 @@
 authors = ["The Rust Project Developers"]
 name = "panic_unwind"
 version = "0.0.0"
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/rust-lang/rust.git"
+description = "Implementation of Rust panics via stack unwinding"
 edition = "2018"
 
 [lib]
diff --git a/library/std/Cargo.toml b/library/std/Cargo.toml
index 22ca7ed09b42a..d2ac771d21c2f 100644
--- a/library/std/Cargo.toml
+++ b/library/std/Cargo.toml
@@ -16,7 +16,7 @@ cfg-if = { version = "0.1.8", features = ['rustc-dep-of-std'] }
 panic_unwind = { path = "../panic_unwind", optional = true }
 panic_abort = { path = "../panic_abort" }
 core = { path = "../core" }
-libc = { version = "0.2.88", default-features = false, features = ['rustc-dep-of-std'] }
+libc = { version = "0.2.89", default-features = false, features = ['rustc-dep-of-std'] }
 compiler_builtins = { version = "0.1.39" }
 profiler_builtins = { path = "../profiler_builtins", optional = true }
 unwind = { path = "../unwind" }
diff --git a/library/std/src/io/mod.rs b/library/std/src/io/mod.rs
index 17002e3b8602d..6abb300054af8 100644
--- a/library/std/src/io/mod.rs
+++ b/library/std/src/io/mod.rs
@@ -514,8 +514,8 @@ pub trait Read {
     /// waiting for data, but if an object needs to block for a read and cannot,
     /// it will typically signal this via an [`Err`] return value.
     ///
-    /// If the return value of this method is [`Ok(n)`], then it must be
-    /// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates
+    /// If the return value of this method is [`Ok(n)`], then implementations must
+    /// guarantee that `0 <= n <= buf.len()`. A nonzero `n` value indicates
     /// that the buffer `buf` has been filled in with `n` bytes of data from this
     /// source. If `n` is `0`, then it can indicate one of two scenarios:
     ///
@@ -529,6 +529,11 @@ pub trait Read {
     /// This may happen for example because fewer bytes are actually available right now
     /// (e. g. being close to end-of-file) or because read() was interrupted by a signal.
     ///
+    /// As this trait is safe to implement, callers cannot rely on `n <= buf.len()` for safety.
+    /// Extra care needs to be taken when `unsafe` functions are used to access the read bytes.
+    /// Callers have to ensure that no unchecked out-of-bounds accesses are possible even if
+    /// `n > buf.len()`.
+    ///
     /// No guarantees are provided about the contents of `buf` when this
     /// function is called, implementations cannot rely on any property of the
     /// contents of `buf` being true. It is recommended that *implementations*
diff --git a/library/std/src/os/linux/mod.rs b/library/std/src/os/linux/mod.rs
index f179a524336fc..f7bb63df0c1ff 100644
--- a/library/std/src/os/linux/mod.rs
+++ b/library/std/src/os/linux/mod.rs
@@ -3,4 +3,5 @@
 #![stable(feature = "raw_ext", since = "1.1.0")]
 
 pub mod fs;
+pub mod process;
 pub mod raw;
diff --git a/library/std/src/os/linux/process.rs b/library/std/src/os/linux/process.rs
new file mode 100644
index 0000000000000..17b9ae82bce4d
--- /dev/null
+++ b/library/std/src/os/linux/process.rs
@@ -0,0 +1,150 @@
+//! Linux-specific extensions to primitives in the `std::process` module.
+
+#![unstable(feature = "linux_pidfd", issue = "82971")]
+
+use crate::io::Result;
+use crate::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd};
+use crate::process;
+use crate::sys::fd::FileDesc;
+use crate::sys_common::{AsInner, AsInnerMut, FromInner, IntoInner};
+
+/// This type represents a file descriptor that refers to a process.
+///
+/// A `PidFd` can be obtained by setting the corresponding option on [`Command`]
+/// with [`create_pidfd`]. Subsequently, the created pidfd can be retrieved
+/// from the [`Child`] by calling [`pidfd`] or [`take_pidfd`].
+///
+/// Example:
+/// ```no_run
+/// #![feature(linux_pidfd)]
+/// use std::os::linux::process::{CommandExt, ChildExt};
+/// use std::process::Command;
+///
+/// let mut child = Command::new("echo")
+///     .create_pidfd(true)
+///     .spawn()
+///     .expect("Failed to spawn child");
+///
+/// let pidfd = child
+///     .take_pidfd()
+///     .expect("Failed to retrieve pidfd");
+///
+/// // The file descriptor will be closed when `pidfd` is dropped.
+/// ```
+/// Refer to the man page of [`pidfd_open(2)`] for further details.
+///
+/// [`Command`]: process::Command
+/// [`create_pidfd`]: CommandExt::create_pidfd
+/// [`Child`]: process::Child
+/// [`pidfd`]: fn@ChildExt::pidfd
+/// [`take_pidfd`]: ChildExt::take_pidfd
+/// [`pidfd_open(2)`]: https://man7.org/linux/man-pages/man2/pidfd_open.2.html
+#[derive(Debug)]
+pub struct PidFd {
+    inner: FileDesc,
+}
+
+impl AsInner<FileDesc> for PidFd {
+    fn as_inner(&self) -> &FileDesc {
+        &self.inner
+    }
+}
+
+impl FromInner<FileDesc> for PidFd {
+    fn from_inner(inner: FileDesc) -> PidFd {
+        PidFd { inner }
+    }
+}
+
+impl IntoInner<FileDesc> for PidFd {
+    fn into_inner(self) -> FileDesc {
+        self.inner
+    }
+}
+
+impl AsRawFd for PidFd {
+    fn as_raw_fd(&self) -> RawFd {
+        self.as_inner().raw()
+    }
+}
+
+impl FromRawFd for PidFd {
+    unsafe fn from_raw_fd(fd: RawFd) -> Self {
+        Self::from_inner(FileDesc::new(fd))
+    }
+}
+
+impl IntoRawFd for PidFd {
+    fn into_raw_fd(self) -> RawFd {
+        self.into_inner().into_raw()
+    }
+}
+
+mod private_child_ext {
+    pub trait Sealed {}
+    impl Sealed for crate::process::Child {}
+}
+
+/// Os-specific extensions for [`Child`]
+///
+/// [`Child`]: process::Child
+pub trait ChildExt: private_child_ext::Sealed {
+    /// Obtains a reference to the [`PidFd`] created for this [`Child`], if available.
+    ///
+    /// A pidfd will only be available if its creation was requested with
+    /// [`create_pidfd`] when the corresponding [`Command`] was created.
+    ///
+    /// Even if requested, a pidfd may not be available due to an older
+    /// version of Linux being in use, or if some other error occurred.
+    ///
+    /// [`Command`]: process::Command
+    /// [`create_pidfd`]: CommandExt::create_pidfd
+    /// [`Child`]: process::Child
+    fn pidfd(&self) -> Result<&PidFd>;
+
+    /// Takes ownership of the [`PidFd`] created for this [`Child`], if available.
+    ///
+    /// A pidfd will only be available if its creation was requested with
+    /// [`create_pidfd`] when the corresponding [`Command`] was created.
+    ///
+    /// Even if requested, a pidfd may not be available due to an older
+    /// version of Linux being in use, or if some other error occurred.
+    ///
+    /// [`Command`]: process::Command
+    /// [`create_pidfd`]: CommandExt::create_pidfd
+    /// [`Child`]: process::Child
+    fn take_pidfd(&mut self) -> Result<PidFd>;
+}
+
+mod private_command_ext {
+    pub trait Sealed {}
+    impl Sealed for crate::process::Command {}
+}
+
+/// Os-specific extensions for [`Command`]
+///
+/// [`Command`]: process::Command
+pub trait CommandExt: private_command_ext::Sealed {
+    /// Sets whether a [`PidFd`](struct@PidFd) should be created for the [`Child`]
+    /// spawned by this [`Command`].
+    /// By default, no pidfd will be created.
+    ///
+    /// The pidfd can be retrieved from the child with [`pidfd`] or [`take_pidfd`].
+    ///
+    /// A pidfd will only be created if it is possible to do so
+    /// in a guaranteed race-free manner (e.g. if the `clone3` system call
+    /// is supported). Otherwise, [`pidfd`] will return an error.
+    ///
+    /// [`Command`]: process::Command
+    /// [`Child`]: process::Child
+    /// [`pidfd`]: fn@ChildExt::pidfd
+    /// [`take_pidfd`]: ChildExt::take_pidfd
+    fn create_pidfd(&mut self, val: bool) -> &mut process::Command;
+}
+
+impl CommandExt for process::Command {
+    fn create_pidfd(&mut self, val: bool) -> &mut process::Command {
+        self.as_inner_mut().create_pidfd(val);
+        self
+    }
+}
diff --git a/library/std/src/process.rs b/library/std/src/process.rs
index f9cfd11e90650..940029adfcf69 100644
--- a/library/std/src/process.rs
+++ b/library/std/src/process.rs
@@ -165,7 +165,7 @@ use crate::sys_common::{AsInner, AsInnerMut, FromInner, IntoInner};
 /// [`wait`]: Child::wait
 #[stable(feature = "process", since = "1.0.0")]
 pub struct Child {
-    handle: imp::Process,
+    pub(crate) handle: imp::Process,
 
     /// The handle for writing to the child's standard input (stdin), if it has
     /// been captured. To avoid partially moving
diff --git a/library/std/src/sys/hermit/mod.rs b/library/std/src/sys/hermit/mod.rs
index f185635b7a0a6..17a51abeb0ef6 100644
--- a/library/std/src/sys/hermit/mod.rs
+++ b/library/std/src/sys/hermit/mod.rs
@@ -32,6 +32,7 @@ pub mod mutex;
 pub mod net;
 pub mod os;
 pub mod path;
+#[path = "../unsupported/pipe.rs"]
 pub mod pipe;
 #[path = "../unsupported/process.rs"]
 pub mod process;
diff --git a/library/std/src/sys/hermit/pipe.rs b/library/std/src/sys/hermit/pipe.rs
deleted file mode 100644
index 10d0925823eb9..0000000000000
--- a/library/std/src/sys/hermit/pipe.rs
+++ /dev/null
@@ -1,38 +0,0 @@
-use crate::io::{self, IoSlice, IoSliceMut};
-use crate::sys::Void;
-
-pub struct AnonPipe(Void);
-
-impl AnonPipe {
-    pub fn read(&self, _buf: &mut [u8]) -> io::Result<usize> {
-        match self.0 {}
-    }
-
-    pub fn read_vectored(&self, _bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
-        match self.0 {}
-    }
-
-    pub fn is_read_vectored(&self) -> bool {
-        match self.0 {}
-    }
-
-    pub fn write(&self, _buf: &[u8]) -> io::Result<usize> {
-        match self.0 {}
-    }
-
-    pub fn write_vectored(&self, _bufs: &[IoSlice<'_>]) -> io::Result<usize> {
-        match self.0 {}
-    }
-
-    pub fn is_write_vectored(&self) -> bool {
-        match self.0 {}
-    }
-
-    pub fn diverge(&self) -> ! {
-        match self.0 {}
-    }
-}
-
-pub fn read2(p1: AnonPipe, _v1: &mut Vec<u8>, _p2: AnonPipe, _v2: &mut Vec<u8>) -> io::Result<()> {
-    match p1.0 {}
-}
diff --git a/library/std/src/sys/unix/process/process_common.rs b/library/std/src/sys/unix/process/process_common.rs
index b9dcc4e4b9e38..3c65b26861543 100644
--- a/library/std/src/sys/unix/process/process_common.rs
+++ b/library/std/src/sys/unix/process/process_common.rs
@@ -79,6 +79,8 @@ pub struct Command {
     stdin: Option<Stdio>,
     stdout: Option<Stdio>,
     stderr: Option<Stdio>,
+    #[cfg(target_os = "linux")]
+    pub(crate) create_pidfd: bool,
 }
 
 // Create a new type for argv, so that we can make it `Send` and `Sync`
@@ -124,6 +126,7 @@ pub enum Stdio {
 }
 
 impl Command {
+    #[cfg(not(target_os = "linux"))]
     pub fn new(program: &OsStr) -> Command {
         let mut saw_nul = false;
         let program = os2c(program, &mut saw_nul);
@@ -144,6 +147,28 @@ impl Command {
         }
     }
 
+    #[cfg(target_os = "linux")]
+    pub fn new(program: &OsStr) -> Command {
+        let mut saw_nul = false;
+        let program = os2c(program, &mut saw_nul);
+        Command {
+            argv: Argv(vec![program.as_ptr(), ptr::null()]),
+            args: vec![program.clone()],
+            program,
+            env: Default::default(),
+            cwd: None,
+            uid: None,
+            gid: None,
+            saw_nul,
+            closures: Vec::new(),
+            groups: None,
+            stdin: None,
+            stdout: None,
+            stderr: None,
+            create_pidfd: false,
+        }
+    }
+
     pub fn set_arg_0(&mut self, arg: &OsStr) {
         // Set a new arg0
         let arg = os2c(arg, &mut self.saw_nul);
@@ -177,6 +202,11 @@ impl Command {
         self.groups = Some(Box::from(groups));
     }
 
+    #[cfg(target_os = "linux")]
+    pub fn create_pidfd(&mut self, val: bool) {
+        self.create_pidfd = val;
+    }
+
     pub fn saw_nul(&self) -> bool {
         self.saw_nul
     }
diff --git a/library/std/src/sys/unix/process/process_unix.rs b/library/std/src/sys/unix/process/process_unix.rs
index 47aaca82af946..47d8e0cd771d0 100644
--- a/library/std/src/sys/unix/process/process_unix.rs
+++ b/library/std/src/sys/unix/process/process_unix.rs
@@ -7,6 +7,9 @@ use crate::sys;
 use crate::sys::cvt;
 use crate::sys::process::process_common::*;
 
+#[cfg(target_os = "linux")]
+use crate::os::linux::process::PidFd;
+
 #[cfg(target_os = "vxworks")]
 use libc::RTP_ID as pid_t;
 
@@ -48,7 +51,8 @@ impl Command {
         // a lock any more because the parent won't do anything and the child is
         // in its own process. Thus the parent drops the lock guard while the child
         // forgets it to avoid unlocking it on a new thread, which would be invalid.
-        let (env_lock, result) = unsafe { (sys::os::env_read_lock(), cvt(libc::fork())?) };
+        let env_lock = sys::os::env_read_lock();
+        let (result, pidfd) = unsafe { self.do_fork()? };
 
         let pid = unsafe {
             match result {
@@ -81,7 +85,7 @@ impl Command {
             }
         };
 
-        let mut p = Process { pid, status: None };
+        let mut p = Process::new(pid, pidfd);
         drop(output);
         let mut bytes = [0; 8];
 
@@ -114,6 +118,92 @@ impl Command {
         }
     }
 
+    // Attempts to fork the process. If successful, returns Ok((0, -1))
+    // in the child, and Ok((child_pid, -1)) in the parent.
+    #[cfg(not(target_os = "linux"))]
+    unsafe fn do_fork(&mut self) -> Result<(pid_t, pid_t), io::Error> {
+        cvt(libc::fork()).map(|res| (res, -1))
+    }
+
+    // Attempts to fork the process. If successful, returns Ok((0, -1))
+    // in the child, and Ok((child_pid, child_pidfd)) in the parent.
+    #[cfg(target_os = "linux")]
+    unsafe fn do_fork(&mut self) -> Result<(pid_t, pid_t), io::Error> {
+        use crate::sync::atomic::{AtomicBool, Ordering};
+
+        static HAS_CLONE3: AtomicBool = AtomicBool::new(true);
+        const CLONE_PIDFD: u64 = 0x00001000;
+
+        #[repr(C)]
+        struct clone_args {
+            flags: u64,
+            pidfd: u64,
+            child_tid: u64,
+            parent_tid: u64,
+            exit_signal: u64,
+            stack: u64,
+            stack_size: u64,
+            tls: u64,
+            set_tid: u64,
+            set_tid_size: u64,
+            cgroup: u64,
+        }
+
+        syscall! {
+            fn clone3(cl_args: *mut clone_args, len: libc::size_t) -> libc::c_long
+        }
+
+        // If we fail to create a pidfd for any reason, this will
+        // stay as -1, which indicates an error.
+        let mut pidfd: pid_t = -1;
+
+        // Attempt to use the `clone3` syscall, which supports more arguments
+        // (in particular, the ability to create a pidfd). If this fails,
+        // we will fall through this block to a call to `fork()`
+        if HAS_CLONE3.load(Ordering::Relaxed) {
+            let mut flags = 0;
+            if self.create_pidfd {
+                flags |= CLONE_PIDFD;
+            }
+
+            let mut args = clone_args {
+                flags,
+                pidfd: &mut pidfd as *mut pid_t as u64,
+                child_tid: 0,
+                parent_tid: 0,
+                exit_signal: libc::SIGCHLD as u64,
+                stack: 0,
+                stack_size: 0,
+                tls: 0,
+                set_tid: 0,
+                set_tid_size: 0,
+                cgroup: 0,
+            };
+
+            let args_ptr = &mut args as *mut clone_args;
+            let args_size = crate::mem::size_of::<clone_args>();
+
+            let res = cvt(clone3(args_ptr, args_size));
+            match res {
+                Ok(n) => return Ok((n as pid_t, pidfd)),
+                Err(e) => match e.raw_os_error() {
+                    // Multiple threads can race to execute this store,
+                    // but that's fine - that just means that multiple threads
+                    // will have tried and failed to execute the same syscall,
+                    // with no other side effects.
+                    Some(libc::ENOSYS) => HAS_CLONE3.store(false, Ordering::Relaxed),
+                    // Fallback to fork if `EPERM` is returned. (e.g. blocked by seccomp)
+                    Some(libc::EPERM) => {}
+                    _ => return Err(e),
+                },
+            }
+        }
+
+        // If we get here, the 'clone3' syscall does not exist
+        // or we do not have permission to call it
+        cvt(libc::fork()).map(|res| (res, pidfd))
+    }
+
     pub fn exec(&mut self, default: Stdio) -> io::Error {
         let envp = self.capture_env();
 
@@ -297,6 +387,7 @@ impl Command {
             || (self.env_saw_path() && !self.program_is_path())
             || !self.get_closures().is_empty()
             || self.get_groups().is_some()
+            || self.create_pidfd
         {
             return Ok(None);
         }
@@ -341,7 +432,7 @@ impl Command {
             None => None,
         };
 
-        let mut p = Process { pid: 0, status: None };
+        let mut p = Process::new(0, -1);
 
         struct PosixSpawnFileActions<'a>(&'a mut MaybeUninit<libc::posix_spawn_file_actions_t>);
 
@@ -430,9 +521,27 @@ impl Command {
 pub struct Process {
     pid: pid_t,
     status: Option<ExitStatus>,
+    // On Linux, stores the pidfd created for this child.
+    // This is None if the user did not request pidfd creation,
+    // or if the pidfd could not be created for some reason
+    // (e.g. the `clone3` syscall was not available).
+    #[cfg(target_os = "linux")]
+    pidfd: Option<PidFd>,
 }
 
 impl Process {
+    #[cfg(target_os = "linux")]
+    fn new(pid: pid_t, pidfd: pid_t) -> Self {
+        use crate::sys_common::FromInner;
+        let pidfd = (pidfd >= 0).then(|| PidFd::from_inner(sys::fd::FileDesc::new(pidfd)));
+        Process { pid, status: None, pidfd }
+    }
+
+    #[cfg(not(target_os = "linux"))]
+    fn new(pid: pid_t, _pidfd: pid_t) -> Self {
+        Process { pid, status: None }
+    }
+
     pub fn id(&self) -> u32 {
         self.pid as u32
     }
@@ -546,6 +655,24 @@ impl fmt::Display for ExitStatus {
     }
 }
 
+#[cfg(target_os = "linux")]
+#[unstable(feature = "linux_pidfd", issue = "82971")]
+impl crate::os::linux::process::ChildExt for crate::process::Child {
+    fn pidfd(&self) -> io::Result<&PidFd> {
+        self.handle
+            .pidfd
+            .as_ref()
+            .ok_or_else(|| Error::new(ErrorKind::Other, "No pidfd was created."))
+    }
+
+    fn take_pidfd(&mut self) -> io::Result<PidFd> {
+        self.handle
+            .pidfd
+            .take()
+            .ok_or_else(|| Error::new(ErrorKind::Other, "No pidfd was created."))
+    }
+}
+
 #[cfg(test)]
 #[path = "process_unix/tests.rs"]
 mod tests;
diff --git a/library/unwind/Cargo.toml b/library/unwind/Cargo.toml
index 4f7a304a59f68..69128591e0672 100644
--- a/library/unwind/Cargo.toml
+++ b/library/unwind/Cargo.toml
@@ -2,6 +2,8 @@
 authors = ["The Rust Project Developers"]
 name = "unwind"
 version = "0.0.0"
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/rust-lang/rust.git"
 edition = "2018"
 include = [
   '/libunwind/*',
diff --git a/src/bootstrap/Cargo.toml b/src/bootstrap/Cargo.toml
index e04128d1b0b25..c14ad6fa5fff4 100644
--- a/src/bootstrap/Cargo.toml
+++ b/src/bootstrap/Cargo.toml
@@ -53,7 +53,7 @@ merge = "0.1.0"
 
 [target.'cfg(windows)'.dependencies.winapi]
 version = "0.3"
-features = ["fileapi", "ioapiset", "jobapi2", "handleapi", "winioctl"]
+features = ["fileapi", "ioapiset", "jobapi2", "handleapi", "winioctl", "psapi", "impl-default"]
 
 [dev-dependencies]
 pretty_assertions = "0.6"
diff --git a/src/bootstrap/bin/rustc.rs b/src/bootstrap/bin/rustc.rs
index 0ab5e9c63c94f..d462dc4d1165c 100644
--- a/src/bootstrap/bin/rustc.rs
+++ b/src/bootstrap/bin/rustc.rs
@@ -17,7 +17,7 @@
 
 use std::env;
 use std::path::PathBuf;
-use std::process::Command;
+use std::process::{Child, Command};
 use std::str::FromStr;
 use std::time::Instant;
 
@@ -163,9 +163,11 @@ fn main() {
     }
 
     let start = Instant::now();
-    let status = {
+    let (child, status) = {
         let errmsg = format!("\nFailed to run:\n{:?}\n-------------", cmd);
-        cmd.status().expect(&errmsg)
+        let mut child = cmd.spawn().expect(&errmsg);
+        let status = child.wait().expect(&errmsg);
+        (child, status)
     };
 
     if env::var_os("RUSTC_PRINT_STEP_TIMINGS").is_some()
@@ -176,7 +178,7 @@ fn main() {
             // If the user requested resource usage data, then
             // include that in addition to the timing output.
             let rusage_data =
-                env::var_os("RUSTC_PRINT_STEP_RUSAGE").and_then(|_| format_rusage_data());
+                env::var_os("RUSTC_PRINT_STEP_RUSAGE").and_then(|_| format_rusage_data(child));
             eprintln!(
                 "[RUSTC-TIMING] {} test:{} {}.{:03}{}{}",
                 crate_name,
@@ -213,19 +215,83 @@ fn main() {
     }
 }
 
-#[cfg(not(unix))]
-/// getrusage is not available on non-unix platforms. So for now, we do not
-/// bother trying to make a shim for it.
-fn format_rusage_data() -> Option<String> {
+#[cfg(all(not(unix), not(windows)))]
+// In the future we can add this for more platforms
+fn format_rusage_data(_child: Child) -> Option<String> {
     None
 }
 
+#[cfg(windows)]
+fn format_rusage_data(child: Child) -> Option<String> {
+    use std::os::windows::io::AsRawHandle;
+    use winapi::um::{processthreadsapi, psapi, timezoneapi};
+    let handle = child.as_raw_handle();
+    macro_rules! try_bool {
+        ($e:expr) => {
+            if $e != 1 {
+                return None;
+            }
+        };
+    }
+
+    let mut user_filetime = Default::default();
+    let mut user_time = Default::default();
+    let mut kernel_filetime = Default::default();
+    let mut kernel_time = Default::default();
+    let mut memory_counters = psapi::PROCESS_MEMORY_COUNTERS::default();
+
+    unsafe {
+        try_bool!(processthreadsapi::GetProcessTimes(
+            handle,
+            &mut Default::default(),
+            &mut Default::default(),
+            &mut kernel_filetime,
+            &mut user_filetime,
+        ));
+        try_bool!(timezoneapi::FileTimeToSystemTime(&user_filetime, &mut user_time));
+        try_bool!(timezoneapi::FileTimeToSystemTime(&kernel_filetime, &mut kernel_time));
+
+        // Unlike on Linux with RUSAGE_CHILDREN, this will only return memory information for the process
+        // with the given handle and none of that process's children.
+        try_bool!(psapi::GetProcessMemoryInfo(
+            handle as _,
+            &mut memory_counters as *mut _ as _,
+            std::mem::size_of::<psapi::PROCESS_MEMORY_COUNTERS_EX>() as u32,
+        ));
+    }
+
+    // Guide on interpreting these numbers:
+    // https://docs.microsoft.com/en-us/windows/win32/psapi/process-memory-usage-information
+    let peak_working_set = memory_counters.PeakWorkingSetSize / 1024;
+    let peak_page_file = memory_counters.PeakPagefileUsage / 1024;
+    let peak_paged_pool = memory_counters.QuotaPeakPagedPoolUsage / 1024;
+    let peak_nonpaged_pool = memory_counters.QuotaPeakNonPagedPoolUsage / 1024;
+    Some(format!(
+        "user: {USER_SEC}.{USER_USEC:03} \
+         sys: {SYS_SEC}.{SYS_USEC:03} \
+         peak working set (kb): {PEAK_WORKING_SET} \
+         peak page file usage (kb): {PEAK_PAGE_FILE} \
+         peak paged pool usage (kb): {PEAK_PAGED_POOL} \
+         peak non-paged pool usage (kb): {PEAK_NONPAGED_POOL} \
+         page faults: {PAGE_FAULTS}",
+        USER_SEC = user_time.wSecond + (user_time.wMinute * 60),
+        USER_USEC = user_time.wMilliseconds,
+        SYS_SEC = kernel_time.wSecond + (kernel_time.wMinute * 60),
+        SYS_USEC = kernel_time.wMilliseconds,
+        PEAK_WORKING_SET = peak_working_set,
+        PEAK_PAGE_FILE = peak_page_file,
+        PEAK_PAGED_POOL = peak_paged_pool,
+        PEAK_NONPAGED_POOL = peak_nonpaged_pool,
+        PAGE_FAULTS = memory_counters.PageFaultCount,
+    ))
+}
+
 #[cfg(unix)]
 /// Tries to build a string with human readable data for several of the rusage
 /// fields. Note that we are focusing mainly on data that we believe to be
 /// supplied on Linux (the `rusage` struct has other fields in it but they are
 /// currently unsupported by Linux).
-fn format_rusage_data() -> Option<String> {
+fn format_rusage_data(_child: Child) -> Option<String> {
     let rusage: libc::rusage = unsafe {
         let mut recv = std::mem::zeroed();
         // -1 is RUSAGE_CHILDREN, which means to get the rusage for all children
diff --git a/src/ci/github-actions/ci.yml b/src/ci/github-actions/ci.yml
index 7125b33699a0c..c0a84444a5928 100644
--- a/src/ci/github-actions/ci.yml
+++ b/src/ci/github-actions/ci.yml
@@ -655,7 +655,7 @@ jobs:
     if: github.event_name == 'push' && github.ref == 'refs/heads/master' && github.repository == 'rust-lang-ci/rust'
     steps:
       - name: checkout the source code
-        uses: actions/checkout@v1
+        uses: actions/checkout@v2
         with:
           fetch-depth: 2
 
diff --git a/src/test/ui/command/command-create-pidfd.rs b/src/test/ui/command/command-create-pidfd.rs
new file mode 100644
index 0000000000000..db728be09dfbc
--- /dev/null
+++ b/src/test/ui/command/command-create-pidfd.rs
@@ -0,0 +1,27 @@
+// run-pass
+// only-linux - pidfds are a linux-specific concept
+
+#![feature(linux_pidfd)]
+use std::os::linux::process::{CommandExt, ChildExt};
+use std::process::Command;
+
+fn main() {
+    // We don't assert the precise value, since the standard library
+    // might have opened other file descriptors before our code runs.
+    let _ = Command::new("echo")
+        .create_pidfd(true)
+        .spawn()
+        .unwrap()
+        .pidfd().expect("failed to obtain pidfd");
+
+    let _ = Command::new("echo")
+        .create_pidfd(false)
+        .spawn()
+        .unwrap()
+        .pidfd().expect_err("pidfd should not have been created when create_pid(false) is set");
+
+    let _ = Command::new("echo")
+        .spawn()
+        .unwrap()
+        .pidfd().expect_err("pidfd should not have been created");
+}
diff --git a/src/test/ui/proc-macro/group-compat-hack/auxiliary/group-compat-hack.rs b/src/test/ui/proc-macro/group-compat-hack/auxiliary/pin-project-internal-0.4.0.rs
similarity index 68%
rename from src/test/ui/proc-macro/group-compat-hack/auxiliary/group-compat-hack.rs
rename to src/test/ui/proc-macro/group-compat-hack/auxiliary/pin-project-internal-0.4.0.rs
index 5cd3b40a2e42a..baa4fd3a10559 100644
--- a/src/test/ui/proc-macro/group-compat-hack/auxiliary/group-compat-hack.rs
+++ b/src/test/ui/proc-macro/group-compat-hack/auxiliary/pin-project-internal-0.4.0.rs
@@ -2,6 +2,10 @@
 // no-prefer-dynamic
 
 #![crate_type = "proc-macro"]
+#![crate_name = "group_compat_hack"]
+
+// This file has an unusual name in order to trigger the back-compat
+// code in the compiler
 
 extern crate proc_macro;
 use proc_macro::TokenStream;
diff --git a/src/test/ui/proc-macro/group-compat-hack/group-compat-hack.rs b/src/test/ui/proc-macro/group-compat-hack/group-compat-hack.rs
index 7f3f5e36f50a9..d9687490cad75 100644
--- a/src/test/ui/proc-macro/group-compat-hack/group-compat-hack.rs
+++ b/src/test/ui/proc-macro/group-compat-hack/group-compat-hack.rs
@@ -1,5 +1,5 @@
 // check-pass
-// aux-build:group-compat-hack.rs
+// aux-build:pin-project-internal-0.4.0.rs
 // compile-flags: -Z span-debug
 
 #![no_std] // Don't load unnecessary hygiene information from std
@@ -51,14 +51,16 @@ mod actix_web_test {
     include!("actix-web/src/extract.rs");
 
     struct Foo;
-    tuple_from_req!(Foo);
+    tuple_from_req!(Foo); //~ WARN using an old version
+    //~| WARN this was previously
 }
 
 mod actix_web_version_test {
     include!("actix-web-2.0.0/src/extract.rs");
 
     struct Foo;
-    tuple_from_req!(Foo);
+    tuple_from_req!(Foo); //~ WARN using an old version
+    //~| WARN this was previously
 }
 
 mod actori_web_test {
diff --git a/src/test/ui/proc-macro/group-compat-hack/group-compat-hack.stderr b/src/test/ui/proc-macro/group-compat-hack/group-compat-hack.stderr
index 9370440a63511..e2b680f8d2760 100644
--- a/src/test/ui/proc-macro/group-compat-hack/group-compat-hack.stderr
+++ b/src/test/ui/proc-macro/group-compat-hack/group-compat-hack.stderr
@@ -31,7 +31,39 @@ LL |     impl_macros!(Foo);
    = note: the `time-macros-impl` crate will stop compiling in futures version of Rust. Please update to the latest version of the `time` crate to avoid breakage
    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-warning: 2 warnings emitted
+warning: using an old version of `actix-web`
+  --> $DIR/actix-web/src/extract.rs:5:34
+   |
+LL |         #[my_macro] struct Three($T);
+   |                                  ^^
+   | 
+  ::: $DIR/group-compat-hack.rs:54:5
+   |
+LL |     tuple_from_req!(Foo);
+   |     --------------------- in this macro invocation
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: the version of `actix-web` you are using might stop compiling in future versions of Rust; please update to the latest version of the `actix-web` crate to avoid breakage
+   = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+warning: using an old version of `actix-web`
+  --> $DIR/actix-web-2.0.0/src/extract.rs:5:34
+   |
+LL |         #[my_macro] struct Three($T);
+   |                                  ^^
+   | 
+  ::: $DIR/group-compat-hack.rs:62:5
+   |
+LL |     tuple_from_req!(Foo);
+   |     --------------------- in this macro invocation
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: the version of `actix-web` you are using might stop compiling in future versions of Rust; please update to the latest version of the `actix-web` crate to avoid breakage
+   = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+warning: 4 warnings emitted
 
 Future incompatibility report: Future breakage date: None, diagnostic:
 warning: using an old version of `time-macros-impl`
@@ -68,3 +100,37 @@ LL |     impl_macros!(Foo);
    = note: the `time-macros-impl` crate will stop compiling in futures version of Rust. Please update to the latest version of the `time` crate to avoid breakage
    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
+Future breakage date: None, diagnostic:
+warning: using an old version of `actix-web`
+  --> $DIR/actix-web/src/extract.rs:5:34
+   |
+LL |         #[my_macro] struct Three($T);
+   |                                  ^^
+   | 
+  ::: $DIR/group-compat-hack.rs:54:5
+   |
+LL |     tuple_from_req!(Foo);
+   |     --------------------- in this macro invocation
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: the version of `actix-web` you are using might stop compiling in future versions of Rust; please update to the latest version of the `actix-web` crate to avoid breakage
+   = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+Future breakage date: None, diagnostic:
+warning: using an old version of `actix-web`
+  --> $DIR/actix-web-2.0.0/src/extract.rs:5:34
+   |
+LL |         #[my_macro] struct Three($T);
+   |                                  ^^
+   | 
+  ::: $DIR/group-compat-hack.rs:62:5
+   |
+LL |     tuple_from_req!(Foo);
+   |     --------------------- in this macro invocation
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: the version of `actix-web` you are using might stop compiling in future versions of Rust; please update to the latest version of the `actix-web` crate to avoid breakage
+   = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
diff --git a/src/test/ui/proc-macro/group-compat-hack/group-compat-hack.stdout b/src/test/ui/proc-macro/group-compat-hack/group-compat-hack.stdout
index 468cb51191517..3fe744e12ff04 100644
--- a/src/test/ui/proc-macro/group-compat-hack/group-compat-hack.stdout
+++ b/src/test/ui/proc-macro/group-compat-hack/group-compat-hack.stdout
@@ -5,6 +5,6 @@ Called proc_macro_hack with TokenStream [Ident { ident: "struct", span: $DIR/tim
 Called proc_macro_hack with TokenStream [Ident { ident: "struct", span: $DIR/js-sys-0.3.17/src/lib.rs:5:21: 5:27 (#24) }, Ident { ident: "Two", span: $DIR/js-sys-0.3.17/src/lib.rs:5:28: 5:31 (#24) }, Group { delimiter: Parenthesis, stream: TokenStream [Ident { ident: "Foo", span: $DIR/group-compat-hack.rs:46:13: 46:16 (#0) }], span: $DIR/js-sys-0.3.17/src/lib.rs:5:31: 5:38 (#24) }, Punct { ch: ';', spacing: Alone, span: $DIR/js-sys-0.3.17/src/lib.rs:5:38: 5:39 (#24) }]
 Called proc_macro_hack with TokenStream [Ident { ident: "struct", span: $DIR/group-compat-hack.rs:39:25: 39:31 (#28) }, Ident { ident: "Three", span: $DIR/group-compat-hack.rs:39:32: 39:37 (#28) }, Group { delimiter: Parenthesis, stream: TokenStream [Group { delimiter: None, stream: TokenStream [Ident { ident: "Foo", span: $DIR/group-compat-hack.rs:47:12: 47:15 (#0) }], span: $DIR/group-compat-hack.rs:39:38: 39:43 (#28) }], span: $DIR/group-compat-hack.rs:39:37: 39:44 (#28) }, Punct { ch: ';', spacing: Alone, span: $DIR/group-compat-hack.rs:39:44: 39:45 (#28) }]
 Called proc_macro_hack with TokenStream [Ident { ident: "struct", span: $DIR/actix-web/src/extract.rs:5:21: 5:27 (#33) }, Ident { ident: "Three", span: $DIR/actix-web/src/extract.rs:5:28: 5:33 (#33) }, Group { delimiter: Parenthesis, stream: TokenStream [Ident { ident: "Foo", span: $DIR/group-compat-hack.rs:54:21: 54:24 (#0) }], span: $DIR/actix-web/src/extract.rs:5:33: 5:37 (#33) }, Punct { ch: ';', spacing: Alone, span: $DIR/actix-web/src/extract.rs:5:37: 5:38 (#33) }]
-Called proc_macro_hack with TokenStream [Ident { ident: "struct", span: $DIR/actix-web-2.0.0/src/extract.rs:5:21: 5:27 (#38) }, Ident { ident: "Three", span: $DIR/actix-web-2.0.0/src/extract.rs:5:28: 5:33 (#38) }, Group { delimiter: Parenthesis, stream: TokenStream [Ident { ident: "Foo", span: $DIR/group-compat-hack.rs:61:21: 61:24 (#0) }], span: $DIR/actix-web-2.0.0/src/extract.rs:5:33: 5:37 (#38) }, Punct { ch: ';', spacing: Alone, span: $DIR/actix-web-2.0.0/src/extract.rs:5:37: 5:38 (#38) }]
-Called proc_macro_hack with TokenStream [Ident { ident: "struct", span: $DIR/actori-web/src/extract.rs:5:21: 5:27 (#43) }, Ident { ident: "Four", span: $DIR/actori-web/src/extract.rs:5:28: 5:32 (#43) }, Group { delimiter: Parenthesis, stream: TokenStream [Ident { ident: "Foo", span: $DIR/group-compat-hack.rs:68:21: 68:24 (#0) }], span: $DIR/actori-web/src/extract.rs:5:32: 5:36 (#43) }, Punct { ch: ';', spacing: Alone, span: $DIR/actori-web/src/extract.rs:5:36: 5:37 (#43) }]
-Called proc_macro_hack with TokenStream [Ident { ident: "struct", span: $DIR/actori-web-2.0.0/src/extract.rs:5:21: 5:27 (#48) }, Ident { ident: "Four", span: $DIR/actori-web-2.0.0/src/extract.rs:5:28: 5:32 (#48) }, Group { delimiter: Parenthesis, stream: TokenStream [Ident { ident: "Foo", span: $DIR/group-compat-hack.rs:75:21: 75:24 (#0) }], span: $DIR/actori-web-2.0.0/src/extract.rs:5:32: 5:36 (#48) }, Punct { ch: ';', spacing: Alone, span: $DIR/actori-web-2.0.0/src/extract.rs:5:36: 5:37 (#48) }]
+Called proc_macro_hack with TokenStream [Ident { ident: "struct", span: $DIR/actix-web-2.0.0/src/extract.rs:5:21: 5:27 (#38) }, Ident { ident: "Three", span: $DIR/actix-web-2.0.0/src/extract.rs:5:28: 5:33 (#38) }, Group { delimiter: Parenthesis, stream: TokenStream [Ident { ident: "Foo", span: $DIR/group-compat-hack.rs:62:21: 62:24 (#0) }], span: $DIR/actix-web-2.0.0/src/extract.rs:5:33: 5:37 (#38) }, Punct { ch: ';', spacing: Alone, span: $DIR/actix-web-2.0.0/src/extract.rs:5:37: 5:38 (#38) }]
+Called proc_macro_hack with TokenStream [Ident { ident: "struct", span: $DIR/actori-web/src/extract.rs:5:21: 5:27 (#43) }, Ident { ident: "Four", span: $DIR/actori-web/src/extract.rs:5:28: 5:32 (#43) }, Group { delimiter: Parenthesis, stream: TokenStream [Group { delimiter: None, stream: TokenStream [Ident { ident: "Foo", span: $DIR/group-compat-hack.rs:70:21: 70:24 (#0) }], span: $DIR/actori-web/src/extract.rs:5:33: 5:35 (#43) }], span: $DIR/actori-web/src/extract.rs:5:32: 5:36 (#43) }, Punct { ch: ';', spacing: Alone, span: $DIR/actori-web/src/extract.rs:5:36: 5:37 (#43) }]
+Called proc_macro_hack with TokenStream [Ident { ident: "struct", span: $DIR/actori-web-2.0.0/src/extract.rs:5:21: 5:27 (#48) }, Ident { ident: "Four", span: $DIR/actori-web-2.0.0/src/extract.rs:5:28: 5:32 (#48) }, Group { delimiter: Parenthesis, stream: TokenStream [Group { delimiter: None, stream: TokenStream [Ident { ident: "Foo", span: $DIR/group-compat-hack.rs:77:21: 77:24 (#0) }], span: $DIR/actori-web-2.0.0/src/extract.rs:5:33: 5:35 (#48) }], span: $DIR/actori-web-2.0.0/src/extract.rs:5:32: 5:36 (#48) }, Punct { ch: ';', spacing: Alone, span: $DIR/actori-web-2.0.0/src/extract.rs:5:36: 5:37 (#48) }]