diff --git a/compiler/rustc_data_structures/src/obligation_forest/mod.rs b/compiler/rustc_data_structures/src/obligation_forest/mod.rs
index a5b2df1da5d6d..29d685ab530d6 100644
--- a/compiler/rustc_data_structures/src/obligation_forest/mod.rs
+++ b/compiler/rustc_data_structures/src/obligation_forest/mod.rs
@@ -336,12 +336,13 @@ impl<O: ForestObligation> ObligationForest<O> {
 
     // Returns Err(()) if we already know this obligation failed.
     fn register_obligation_at(&mut self, obligation: O, parent: Option<usize>) -> Result<(), ()> {
-        if self.done_cache.contains(&obligation.as_cache_key()) {
+        let cache_key = obligation.as_cache_key();
+        if self.done_cache.contains(&cache_key) {
             debug!("register_obligation_at: ignoring already done obligation: {:?}", obligation);
             return Ok(());
         }
 
-        match self.active_cache.entry(obligation.as_cache_key()) {
+        match self.active_cache.entry(cache_key.clone()) {
             Entry::Occupied(o) => {
                 let node = &mut self.nodes[*o.get()];
                 if let Some(parent_index) = parent {
@@ -365,7 +366,7 @@ impl<O: ForestObligation> ObligationForest<O> {
                     && self
                         .error_cache
                         .get(&obligation_tree_id)
-                        .map(|errors| errors.contains(&obligation.as_cache_key()))
+                        .map(|errors| errors.contains(&cache_key))
                         .unwrap_or(false);
 
                 if already_failed {
diff --git a/compiler/rustc_expand/src/module.rs b/compiler/rustc_expand/src/module.rs
index 993522d01d867..4d777049f0d62 100644
--- a/compiler/rustc_expand/src/module.rs
+++ b/compiler/rustc_expand/src/module.rs
@@ -36,7 +36,7 @@ crate struct ParsedExternalMod {
 pub enum ModError<'a> {
     CircularInclusion(Vec<PathBuf>),
     ModInBlock(Option<Ident>),
-    FileNotFound(Ident, PathBuf),
+    FileNotFound(Ident, PathBuf, PathBuf),
     MultipleCandidates(Ident, PathBuf, PathBuf),
     ParserError(DiagnosticBuilder<'a>),
 }
@@ -219,7 +219,7 @@ pub fn default_submod_path<'a>(
             file_path: secondary_path,
             dir_ownership: DirOwnership::Owned { relative: None },
         }),
-        (false, false) => Err(ModError::FileNotFound(ident, default_path)),
+        (false, false) => Err(ModError::FileNotFound(ident, default_path, secondary_path)),
         (true, true) => Err(ModError::MultipleCandidates(ident, default_path, secondary_path)),
     }
 }
@@ -247,7 +247,7 @@ impl ModError<'_> {
                 }
                 err
             }
-            ModError::FileNotFound(ident, default_path) => {
+            ModError::FileNotFound(ident, default_path, secondary_path) => {
                 let mut err = struct_span_err!(
                     diag,
                     span,
@@ -256,9 +256,10 @@ impl ModError<'_> {
                     ident,
                 );
                 err.help(&format!(
-                    "to create the module `{}`, create file \"{}\"",
+                    "to create the module `{}`, create file \"{}\" or \"{}\"",
                     ident,
                     default_path.display(),
+                    secondary_path.display(),
                 ));
                 err
             }
diff --git a/compiler/rustc_mir/src/interpret/intrinsics.rs b/compiler/rustc_mir/src/interpret/intrinsics.rs
index dea1b11331549..292306f6cde6e 100644
--- a/compiler/rustc_mir/src/interpret/intrinsics.rs
+++ b/compiler/rustc_mir/src/interpret/intrinsics.rs
@@ -323,7 +323,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 self.write_scalar(result, dest)?;
             }
             sym::copy => {
-                self.copy(&args[0], &args[1], &args[2], /*nonoverlapping*/ false)?;
+                self.copy_intrinsic(&args[0], &args[1], &args[2], /*nonoverlapping*/ false)?;
             }
             sym::offset => {
                 let ptr = self.read_scalar(&args[0])?.check_init()?;
@@ -530,4 +530,36 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         )?;
         Ok(offset_ptr)
     }
+
+    /// Copy `count*size_of::<T>()` many bytes from `*src` to `*dst`.
+    pub(crate) fn copy_intrinsic(
+        &mut self,
+        src: &OpTy<'tcx, <M as Machine<'mir, 'tcx>>::PointerTag>,
+        dst: &OpTy<'tcx, <M as Machine<'mir, 'tcx>>::PointerTag>,
+        count: &OpTy<'tcx, <M as Machine<'mir, 'tcx>>::PointerTag>,
+        nonoverlapping: bool,
+    ) -> InterpResult<'tcx> {
+        let count = self.read_scalar(&count)?.to_machine_usize(self)?;
+        let layout = self.layout_of(src.layout.ty.builtin_deref(true).unwrap().ty)?;
+        let (size, align) = (layout.size, layout.align.abi);
+        let size = size.checked_mul(count, self).ok_or_else(|| {
+            err_ub_format!(
+                "overflow computing total size of `{}`",
+                if nonoverlapping { "copy_nonoverlapping" } else { "copy" }
+            )
+        })?;
+
+        // Make sure we check both pointers for an access of the total size and aligment,
+        // *even if* the total size is 0.
+        let src =
+            self.memory.check_ptr_access(self.read_scalar(&src)?.check_init()?, size, align)?;
+
+        let dst =
+            self.memory.check_ptr_access(self.read_scalar(&dst)?.check_init()?, size, align)?;
+
+        if let (Some(src), Some(dst)) = (src, dst) {
+            self.memory.copy(src, dst, size, nonoverlapping)?;
+        }
+        Ok(())
+    }
 }
diff --git a/compiler/rustc_mir/src/interpret/step.rs b/compiler/rustc_mir/src/interpret/step.rs
index 6084f67abd78e..5a10ffe6d6199 100644
--- a/compiler/rustc_mir/src/interpret/step.rs
+++ b/compiler/rustc_mir/src/interpret/step.rs
@@ -2,7 +2,6 @@
 //!
 //! The main entry point is the `step` method.
 
-use crate::interpret::OpTy;
 use rustc_middle::mir;
 use rustc_middle::mir::interpret::{InterpResult, Scalar};
 use rustc_target::abi::LayoutOf;
@@ -119,7 +118,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 let src = self.eval_operand(src, None)?;
                 let dst = self.eval_operand(dst, None)?;
                 let count = self.eval_operand(count, None)?;
-                self.copy(&src, &dst, &count, /* nonoverlapping */ true)?;
+                self.copy_intrinsic(&src, &dst, &count, /* nonoverlapping */ true)?;
             }
 
             // Statements we do not track.
@@ -149,37 +148,6 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         Ok(())
     }
 
-    pub(crate) fn copy(
-        &mut self,
-        src: &OpTy<'tcx, <M as Machine<'mir, 'tcx>>::PointerTag>,
-        dst: &OpTy<'tcx, <M as Machine<'mir, 'tcx>>::PointerTag>,
-        count: &OpTy<'tcx, <M as Machine<'mir, 'tcx>>::PointerTag>,
-        nonoverlapping: bool,
-    ) -> InterpResult<'tcx> {
-        let count = self.read_scalar(&count)?.to_machine_usize(self)?;
-        let layout = self.layout_of(src.layout.ty.builtin_deref(true).unwrap().ty)?;
-        let (size, align) = (layout.size, layout.align.abi);
-        let size = size.checked_mul(count, self).ok_or_else(|| {
-            err_ub_format!(
-                "overflow computing total size of `{}`",
-                if nonoverlapping { "copy_nonoverlapping" } else { "copy" }
-            )
-        })?;
-
-        // Make sure we check both pointers for an access of the total size and aligment,
-        // *even if* the total size is 0.
-        let src =
-            self.memory.check_ptr_access(self.read_scalar(&src)?.check_init()?, size, align)?;
-
-        let dst =
-            self.memory.check_ptr_access(self.read_scalar(&dst)?.check_init()?, size, align)?;
-
-        if let (Some(src), Some(dst)) = (src, dst) {
-            self.memory.copy(src, dst, size, nonoverlapping)?;
-        }
-        Ok(())
-    }
-
     /// Evaluate an assignment statement.
     ///
     /// There is no separate `eval_rvalue` function. Instead, the code for handling each rvalue
diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs
index 0f7b8ebd376b9..d537741c749c5 100644
--- a/compiler/rustc_parse/src/parser/ty.rs
+++ b/compiler/rustc_parse/src/parser/ty.rs
@@ -470,7 +470,7 @@ impl<'a> Parser<'a> {
     /// Is a `dyn B0 + ... + Bn` type allowed here?
     fn is_explicit_dyn_type(&mut self) -> bool {
         self.check_keyword(kw::Dyn)
-            && (self.token.uninterpolated_span().rust_2018()
+            && (!self.token.uninterpolated_span().rust_2015()
                 || self.look_ahead(1, |t| {
                     t.can_begin_bound() && !can_continue_type_after_non_fn_ident(t)
                 }))
@@ -539,7 +539,21 @@ impl<'a> Parser<'a> {
     ) -> PResult<'a, GenericBounds> {
         let mut bounds = Vec::new();
         let mut negative_bounds = Vec::new();
-        while self.can_begin_bound() {
+
+        while self.can_begin_bound() || self.token.is_keyword(kw::Dyn) {
+            if self.token.is_keyword(kw::Dyn) {
+                // Account for `&dyn Trait + dyn Other`.
+                self.struct_span_err(self.token.span, "invalid `dyn` keyword")
+                    .help("`dyn` is only needed at the start of a trait `+`-separated list")
+                    .span_suggestion(
+                        self.token.span,
+                        "remove this keyword",
+                        String::new(),
+                        Applicability::MachineApplicable,
+                    )
+                    .emit();
+                self.bump();
+            }
             match self.parse_generic_bound()? {
                 Ok(bound) => bounds.push(bound),
                 Err(neg_sp) => negative_bounds.push(neg_sp),
@@ -721,7 +735,26 @@ impl<'a> Parser<'a> {
         let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
         let path = self.parse_path(PathStyle::Type)?;
         if has_parens {
-            self.expect(&token::CloseDelim(token::Paren))?;
+            if self.token.is_like_plus() {
+                // Someone has written something like `&dyn (Trait + Other)`. The correct code
+                // would be `&(dyn Trait + Other)`, but we don't have access to the appropriate
+                // span to suggest that. When written as `&dyn Trait + Other`, an appropriate
+                // suggestion is given.
+                let bounds = vec![];
+                self.parse_remaining_bounds(bounds, true)?;
+                self.expect(&token::CloseDelim(token::Paren))?;
+                let sp = vec![lo, self.prev_token.span];
+                let sugg: Vec<_> = sp.iter().map(|sp| (*sp, String::new())).collect();
+                self.struct_span_err(sp, "incorrect braces around trait bounds")
+                    .multipart_suggestion(
+                        "remove the parentheses",
+                        sugg,
+                        Applicability::MachineApplicable,
+                    )
+                    .emit();
+            } else {
+                self.expect(&token::CloseDelim(token::Paren))?;
+            }
         }
 
         let modifier = modifiers.to_trait_bound_modifier();
diff --git a/library/alloc/src/collections/btree/map.rs b/library/alloc/src/collections/btree/map.rs
index 971244718b4ad..0a46387c34e9c 100644
--- a/library/alloc/src/collections/btree/map.rs
+++ b/library/alloc/src/collections/btree/map.rs
@@ -398,12 +398,12 @@ impl<K, V: fmt::Debug> fmt::Debug for ValuesMut<'_, K, V> {
 /// See its documentation for more.
 ///
 /// [`into_keys`]: BTreeMap::into_keys
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 pub struct IntoKeys<K, V> {
     inner: IntoIter<K, V>,
 }
 
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K: fmt::Debug, V> fmt::Debug for IntoKeys<K, V> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_list().entries(self.inner.iter().map(|(key, _)| key)).finish()
@@ -416,12 +416,12 @@ impl<K: fmt::Debug, V> fmt::Debug for IntoKeys<K, V> {
 /// See its documentation for more.
 ///
 /// [`into_values`]: BTreeMap::into_values
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 pub struct IntoValues<K, V> {
     inner: IntoIter<K, V>,
 }
 
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K, V: fmt::Debug> fmt::Debug for IntoValues<K, V> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_list().entries(self.inner.iter().map(|(_, val)| val)).finish()
@@ -1242,7 +1242,6 @@ impl<K, V> BTreeMap<K, V> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(map_into_keys_values)]
     /// use std::collections::BTreeMap;
     ///
     /// let mut a = BTreeMap::new();
@@ -1253,7 +1252,7 @@ impl<K, V> BTreeMap<K, V> {
     /// assert_eq!(keys, [1, 2]);
     /// ```
     #[inline]
-    #[unstable(feature = "map_into_keys_values", issue = "75294")]
+    #[stable(feature = "map_into_keys_values", since = "1.54.0")]
     pub fn into_keys(self) -> IntoKeys<K, V> {
         IntoKeys { inner: self.into_iter() }
     }
@@ -1265,7 +1264,6 @@ impl<K, V> BTreeMap<K, V> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(map_into_keys_values)]
     /// use std::collections::BTreeMap;
     ///
     /// let mut a = BTreeMap::new();
@@ -1276,7 +1274,7 @@ impl<K, V> BTreeMap<K, V> {
     /// assert_eq!(values, ["hello", "goodbye"]);
     /// ```
     #[inline]
-    #[unstable(feature = "map_into_keys_values", issue = "75294")]
+    #[stable(feature = "map_into_keys_values", since = "1.54.0")]
     pub fn into_values(self) -> IntoValues<K, V> {
         IntoValues { inner: self.into_iter() }
     }
@@ -1776,7 +1774,7 @@ impl<'a, K, V> Range<'a, K, V> {
     }
 }
 
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K, V> Iterator for IntoKeys<K, V> {
     type Item = K;
 
@@ -1801,24 +1799,24 @@ impl<K, V> Iterator for IntoKeys<K, V> {
     }
 }
 
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K, V> DoubleEndedIterator for IntoKeys<K, V> {
     fn next_back(&mut self) -> Option<K> {
         self.inner.next_back().map(|(k, _)| k)
     }
 }
 
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K, V> ExactSizeIterator for IntoKeys<K, V> {
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
 
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K, V> FusedIterator for IntoKeys<K, V> {}
 
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K, V> Iterator for IntoValues<K, V> {
     type Item = V;
 
@@ -1835,21 +1833,21 @@ impl<K, V> Iterator for IntoValues<K, V> {
     }
 }
 
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K, V> DoubleEndedIterator for IntoValues<K, V> {
     fn next_back(&mut self) -> Option<V> {
         self.inner.next_back().map(|(_, v)| v)
     }
 }
 
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K, V> ExactSizeIterator for IntoValues<K, V> {
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
 
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K, V> FusedIterator for IntoValues<K, V> {}
 
 #[stable(feature = "btree_range", since = "1.17.0")]
diff --git a/library/core/src/intrinsics.rs b/library/core/src/intrinsics.rs
index d7dd7ee02c1f4..0034de9ad1bfa 100644
--- a/library/core/src/intrinsics.rs
+++ b/library/core/src/intrinsics.rs
@@ -723,7 +723,7 @@ extern "rust-intrinsic" {
     /// macro, which panics when it is executed, it is *undefined behavior* to
     /// reach code marked with this function.
     ///
-    /// The stabilized version of this intrinsic is [`core::hint::unreachable_unchecked`](crate::hint::unreachable_unchecked).
+    /// The stabilized version of this intrinsic is [`core::hint::unreachable_unchecked`].
     #[rustc_const_unstable(feature = "const_unreachable_unchecked", issue = "53188")]
     pub fn unreachable() -> !;
 
@@ -768,13 +768,13 @@ extern "rust-intrinsic" {
     /// More specifically, this is the offset in bytes between successive
     /// items of the same type, including alignment padding.
     ///
-    /// The stabilized version of this intrinsic is [`core::mem::size_of`](crate::mem::size_of).
+    /// The stabilized version of this intrinsic is [`core::mem::size_of`].
     #[rustc_const_stable(feature = "const_size_of", since = "1.40.0")]
     pub fn size_of<T>() -> usize;
 
     /// The minimum alignment of a type.
     ///
-    /// The stabilized version of this intrinsic is [`core::mem::align_of`](crate::mem::align_of).
+    /// The stabilized version of this intrinsic is [`core::mem::align_of`].
     #[rustc_const_stable(feature = "const_min_align_of", since = "1.40.0")]
     pub fn min_align_of<T>() -> usize;
     /// The preferred alignment of a type.
@@ -790,13 +790,13 @@ extern "rust-intrinsic" {
     pub fn size_of_val<T: ?Sized>(_: *const T) -> usize;
     /// The required alignment of the referenced value.
     ///
-    /// The stabilized version of this intrinsic is [`core::mem::align_of_val`](crate::mem::align_of_val).
+    /// The stabilized version of this intrinsic is [`core::mem::align_of_val`].
     #[rustc_const_unstable(feature = "const_align_of_val", issue = "46571")]
     pub fn min_align_of_val<T: ?Sized>(_: *const T) -> usize;
 
     /// Gets a static string slice containing the name of a type.
     ///
-    /// The stabilized version of this intrinsic is [`core::any::type_name`](crate::any::type_name).
+    /// The stabilized version of this intrinsic is [`core::any::type_name`].
     #[rustc_const_unstable(feature = "const_type_name", issue = "63084")]
     pub fn type_name<T: ?Sized>() -> &'static str;
 
@@ -804,7 +804,7 @@ extern "rust-intrinsic" {
     /// function will return the same value for a type regardless of whichever
     /// crate it is invoked in.
     ///
-    /// The stabilized version of this intrinsic is [`core::any::TypeId::of`](crate::any::TypeId::of).
+    /// The stabilized version of this intrinsic is [`core::any::TypeId::of`].
     #[rustc_const_unstable(feature = "const_type_id", issue = "77125")]
     pub fn type_id<T: ?Sized + 'static>() -> u64;
 
@@ -829,7 +829,7 @@ extern "rust-intrinsic" {
 
     /// Gets a reference to a static `Location` indicating where it was called.
     ///
-    /// Consider using [`core::panic::Location::caller`](crate::panic::Location::caller) instead.
+    /// Consider using [`core::panic::Location::caller`] instead.
     #[rustc_const_unstable(feature = "const_caller_location", issue = "76156")]
     pub fn caller_location() -> &'static crate::panic::Location<'static>;
 
@@ -1158,11 +1158,11 @@ extern "rust-intrinsic" {
 
     /// Performs a volatile load from the `src` pointer.
     ///
-    /// The stabilized version of this intrinsic is [`core::ptr::read_volatile`](crate::ptr::read_volatile).
+    /// The stabilized version of this intrinsic is [`core::ptr::read_volatile`].
     pub fn volatile_load<T>(src: *const T) -> T;
     /// Performs a volatile store to the `dst` pointer.
     ///
-    /// The stabilized version of this intrinsic is [`core::ptr::write_volatile`](crate::ptr::write_volatile).
+    /// The stabilized version of this intrinsic is [`core::ptr::write_volatile`].
     pub fn volatile_store<T>(dst: *mut T, val: T);
 
     /// Performs a volatile load from the `src` pointer
@@ -1703,7 +1703,7 @@ extern "rust-intrinsic" {
     /// Returns the value of the discriminant for the variant in 'v';
     /// if `T` has no discriminant, returns `0`.
     ///
-    /// The stabilized version of this intrinsic is [`core::mem::discriminant`](crate::mem::discriminant).
+    /// The stabilized version of this intrinsic is [`core::mem::discriminant`].
     #[rustc_const_unstable(feature = "const_discriminant", issue = "69821")]
     pub fn discriminant_value<T>(v: &T) -> <T as DiscriminantKind>::Discriminant;
 
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 0e2c140c367a9..cbabf55d17b66 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -169,6 +169,10 @@
 #![feature(int_error_matching)]
 #![deny(unsafe_op_in_unsafe_fn)]
 
+// allow using `core::` in intra-doc links
+#[allow(unused_extern_crates)]
+extern crate self as core;
+
 #[prelude_import]
 #[allow(unused)]
 use prelude::v1::*;
diff --git a/library/core/src/mem/maybe_uninit.rs b/library/core/src/mem/maybe_uninit.rs
index f77acdd618072..10219201a40d3 100644
--- a/library/core/src/mem/maybe_uninit.rs
+++ b/library/core/src/mem/maybe_uninit.rs
@@ -870,7 +870,7 @@ impl<T> MaybeUninit<T> {
         // SAFETY:
         // * The caller guarantees that all elements of the array are initialized
         // * `MaybeUninit<T>` and T are guaranteed to have the same layout
-        // * MaybeUnint does not drop, so there are no double-frees
+        // * `MaybeUninit` does not drop, so there are no double-frees
         // And thus the conversion is safe
         unsafe {
             intrinsics::assert_inhabited::<[T; N]>();
diff --git a/library/std/src/collections/hash/map.rs b/library/std/src/collections/hash/map.rs
index bdf559847cc85..a1f52a9c2e880 100644
--- a/library/std/src/collections/hash/map.rs
+++ b/library/std/src/collections/hash/map.rs
@@ -962,7 +962,6 @@ where
     /// # Examples
     ///
     /// ```
-    /// #![feature(map_into_keys_values)]
     /// use std::collections::HashMap;
     ///
     /// let mut map = HashMap::new();
@@ -973,7 +972,7 @@ where
     /// let vec: Vec<&str> = map.into_keys().collect();
     /// ```
     #[inline]
-    #[unstable(feature = "map_into_keys_values", issue = "75294")]
+    #[stable(feature = "map_into_keys_values", since = "1.54.0")]
     pub fn into_keys(self) -> IntoKeys<K, V> {
         IntoKeys { inner: self.into_iter() }
     }
@@ -985,7 +984,6 @@ where
     /// # Examples
     ///
     /// ```
-    /// #![feature(map_into_keys_values)]
     /// use std::collections::HashMap;
     ///
     /// let mut map = HashMap::new();
@@ -996,7 +994,7 @@ where
     /// let vec: Vec<i32> = map.into_values().collect();
     /// ```
     #[inline]
-    #[unstable(feature = "map_into_keys_values", issue = "75294")]
+    #[stable(feature = "map_into_keys_values", since = "1.54.0")]
     pub fn into_values(self) -> IntoValues<K, V> {
         IntoValues { inner: self.into_iter() }
     }
@@ -1405,15 +1403,13 @@ pub struct ValuesMut<'a, K: 'a, V: 'a> {
 /// # Example
 ///
 /// ```
-/// #![feature(map_into_keys_values)]
-///
 /// use std::collections::HashMap;
 ///
 /// let mut map = HashMap::new();
 /// map.insert("a", 1);
 /// let iter_keys = map.into_keys();
 /// ```
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 pub struct IntoKeys<K, V> {
     inner: IntoIter<K, V>,
 }
@@ -1428,15 +1424,13 @@ pub struct IntoKeys<K, V> {
 /// # Example
 ///
 /// ```
-/// #![feature(map_into_keys_values)]
-///
 /// use std::collections::HashMap;
 ///
 /// let mut map = HashMap::new();
 /// map.insert("a", 1);
 /// let iter_keys = map.into_values();
 /// ```
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 pub struct IntoValues<K, V> {
     inner: IntoIter<K, V>,
 }
@@ -2137,7 +2131,7 @@ impl<K, V: fmt::Debug> fmt::Debug for ValuesMut<'_, K, V> {
     }
 }
 
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K, V> Iterator for IntoKeys<K, V> {
     type Item = K;
 
@@ -2150,24 +2144,24 @@ impl<K, V> Iterator for IntoKeys<K, V> {
         self.inner.size_hint()
     }
 }
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K, V> ExactSizeIterator for IntoKeys<K, V> {
     #[inline]
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K, V> FusedIterator for IntoKeys<K, V> {}
 
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K: Debug, V> fmt::Debug for IntoKeys<K, V> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_list().entries(self.inner.iter().map(|(k, _)| k)).finish()
     }
 }
 
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K, V> Iterator for IntoValues<K, V> {
     type Item = V;
 
@@ -2180,17 +2174,17 @@ impl<K, V> Iterator for IntoValues<K, V> {
         self.inner.size_hint()
     }
 }
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K, V> ExactSizeIterator for IntoValues<K, V> {
     #[inline]
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K, V> FusedIterator for IntoValues<K, V> {}
 
-#[unstable(feature = "map_into_keys_values", issue = "75294")]
+#[stable(feature = "map_into_keys_values", since = "1.54.0")]
 impl<K, V: Debug> fmt::Debug for IntoValues<K, V> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_list().entries(self.inner.iter().map(|(_, v)| v)).finish()
diff --git a/src/librustdoc/html/highlight.rs b/src/librustdoc/html/highlight.rs
index 7130a6bc1e888..f631f627fc255 100644
--- a/src/librustdoc/html/highlight.rs
+++ b/src/librustdoc/html/highlight.rs
@@ -13,7 +13,6 @@ use std::iter::Peekable;
 use rustc_lexer::{LiteralKind, TokenKind};
 use rustc_span::edition::Edition;
 use rustc_span::symbol::Symbol;
-use rustc_span::with_default_session_globals;
 
 use super::format::Buffer;
 
@@ -238,28 +237,26 @@ impl<'a> Classifier<'a> {
     /// possibly giving it an HTML span with a class specifying what flavor of
     /// token is used.
     fn highlight(mut self, sink: &mut dyn FnMut(Highlight<'a>)) {
-        with_default_session_globals(|| {
-            loop {
-                if self
-                    .tokens
-                    .peek()
-                    .map(|t| matches!(t.0, TokenKind::Colon | TokenKind::Ident))
-                    .unwrap_or(false)
-                {
-                    let tokens = self.get_full_ident_path();
-                    for (token, start, end) in tokens {
-                        let text = &self.src[start..end];
-                        self.advance(token, text, sink);
-                        self.byte_pos += text.len() as u32;
-                    }
-                }
-                if let Some((token, text)) = self.next() {
+        loop {
+            if self
+                .tokens
+                .peek()
+                .map(|t| matches!(t.0, TokenKind::Colon | TokenKind::Ident))
+                .unwrap_or(false)
+            {
+                let tokens = self.get_full_ident_path();
+                for (token, start, end) in tokens {
+                    let text = &self.src[start..end];
                     self.advance(token, text, sink);
-                } else {
-                    break;
+                    self.byte_pos += text.len() as u32;
                 }
             }
-        })
+            if let Some((token, text)) = self.next() {
+                self.advance(token, text, sink);
+            } else {
+                break;
+            }
+        }
     }
 
     /// Single step of highlighting. This will classify `token`, but maybe also
diff --git a/src/librustdoc/html/highlight/tests.rs b/src/librustdoc/html/highlight/tests.rs
index 305cf61091dc6..a0da2c963d167 100644
--- a/src/librustdoc/html/highlight/tests.rs
+++ b/src/librustdoc/html/highlight/tests.rs
@@ -2,6 +2,7 @@ use super::write_code;
 use crate::html::format::Buffer;
 use expect_test::expect_file;
 use rustc_span::edition::Edition;
+use rustc_span::with_default_session_globals;
 
 const STYLE: &str = r#"
 <style>
@@ -17,21 +18,25 @@ const STYLE: &str = r#"
 
 #[test]
 fn test_html_highlighting() {
-    let src = include_str!("fixtures/sample.rs");
-    let html = {
-        let mut out = Buffer::new();
-        write_code(&mut out, src, Edition::Edition2018);
-        format!("{}<pre><code>{}</code></pre>\n", STYLE, out.into_inner())
-    };
-    expect_file!["fixtures/sample.html"].assert_eq(&html);
+    with_default_session_globals(|| {
+        let src = include_str!("fixtures/sample.rs");
+        let html = {
+            let mut out = Buffer::new();
+            write_code(&mut out, src, Edition::Edition2018);
+            format!("{}<pre><code>{}</code></pre>\n", STYLE, out.into_inner())
+        };
+        expect_file!["fixtures/sample.html"].assert_eq(&html);
+    });
 }
 
 #[test]
 fn test_dos_backline() {
-    let src = "pub fn foo() {\r\n\
+    with_default_session_globals(|| {
+        let src = "pub fn foo() {\r\n\
     println!(\"foo\");\r\n\
 }\r\n";
-    let mut html = Buffer::new();
-    write_code(&mut html, src, Edition::Edition2018);
-    expect_file!["fixtures/dos_line.html"].assert_eq(&html.into_inner());
+        let mut html = Buffer::new();
+        write_code(&mut html, src, Edition::Edition2018);
+        expect_file!["fixtures/dos_line.html"].assert_eq(&html.into_inner());
+    });
 }
diff --git a/src/test/ui/error-codes/E0583.stderr b/src/test/ui/error-codes/E0583.stderr
index dbe700355957b..c7bbbf114997d 100644
--- a/src/test/ui/error-codes/E0583.stderr
+++ b/src/test/ui/error-codes/E0583.stderr
@@ -4,7 +4,7 @@ error[E0583]: file not found for module `module_that_doesnt_exist`
 LL | mod module_that_doesnt_exist;
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: to create the module `module_that_doesnt_exist`, create file "$DIR/module_that_doesnt_exist.rs"
+   = help: to create the module `module_that_doesnt_exist`, create file "$DIR/module_that_doesnt_exist.rs" or "$DIR/module_that_doesnt_exist/mod.rs"
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/invalid-module-declaration/invalid-module-declaration.stderr b/src/test/ui/invalid-module-declaration/invalid-module-declaration.stderr
index 52296042eb4a7..7bc8efd7e4a97 100644
--- a/src/test/ui/invalid-module-declaration/invalid-module-declaration.stderr
+++ b/src/test/ui/invalid-module-declaration/invalid-module-declaration.stderr
@@ -4,7 +4,7 @@ error[E0583]: file not found for module `baz`
 LL | pub mod baz;
    | ^^^^^^^^^^^^
    |
-   = help: to create the module `baz`, create file "$DIR/auxiliary/foo/bar/baz.rs"
+   = help: to create the module `baz`, create file "$DIR/auxiliary/foo/bar/baz.rs" or "$DIR/auxiliary/foo/bar/baz/mod.rs"
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/missing_non_modrs_mod/missing_non_modrs_mod.stderr b/src/test/ui/missing_non_modrs_mod/missing_non_modrs_mod.stderr
index 91b3fe15c4be7..31e4206a5463a 100644
--- a/src/test/ui/missing_non_modrs_mod/missing_non_modrs_mod.stderr
+++ b/src/test/ui/missing_non_modrs_mod/missing_non_modrs_mod.stderr
@@ -4,7 +4,7 @@ error[E0583]: file not found for module `missing`
 LL | mod missing;
    | ^^^^^^^^^^^^
    |
-   = help: to create the module `missing`, create file "$DIR/foo/missing.rs"
+   = help: to create the module `missing`, create file "$DIR/foo/missing.rs" or "$DIR/foo/missing/mod.rs"
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/missing_non_modrs_mod/missing_non_modrs_mod_inline.stderr b/src/test/ui/missing_non_modrs_mod/missing_non_modrs_mod_inline.stderr
index f519de46c767f..9d252398b7a14 100644
--- a/src/test/ui/missing_non_modrs_mod/missing_non_modrs_mod_inline.stderr
+++ b/src/test/ui/missing_non_modrs_mod/missing_non_modrs_mod_inline.stderr
@@ -4,7 +4,7 @@ error[E0583]: file not found for module `missing`
 LL |     mod missing;
    |     ^^^^^^^^^^^^
    |
-   = help: to create the module `missing`, create file "$DIR/foo_inline/inline/missing.rs"
+   = help: to create the module `missing`, create file "$DIR/foo_inline/inline/missing.rs" or "$DIR/foo_inline/inline/missing/mod.rs"
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/mod_file_not_exist.stderr b/src/test/ui/parser/mod_file_not_exist.stderr
index 4e08125625f0a..62456d518804f 100644
--- a/src/test/ui/parser/mod_file_not_exist.stderr
+++ b/src/test/ui/parser/mod_file_not_exist.stderr
@@ -4,7 +4,7 @@ error[E0583]: file not found for module `not_a_real_file`
 LL | mod not_a_real_file;
    | ^^^^^^^^^^^^^^^^^^^^
    |
-   = help: to create the module `not_a_real_file`, create file "$DIR/not_a_real_file.rs"
+   = help: to create the module `not_a_real_file`, create file "$DIR/not_a_real_file.rs" or "$DIR/not_a_real_file/mod.rs"
 
 error[E0433]: failed to resolve: use of undeclared crate or module `mod_file_aux`
   --> $DIR/mod_file_not_exist.rs:7:16
diff --git a/src/test/ui/parser/trait-object-delimiters.rs b/src/test/ui/parser/trait-object-delimiters.rs
new file mode 100644
index 0000000000000..650ab57226187
--- /dev/null
+++ b/src/test/ui/parser/trait-object-delimiters.rs
@@ -0,0 +1,17 @@
+// edition:2018
+
+fn foo1(_: &dyn Drop + AsRef<str>) {} //~ ERROR ambiguous `+` in a type
+//~^ ERROR only auto traits can be used as additional traits in a trait object
+
+fn foo2(_: &dyn (Drop + AsRef<str>)) {} //~ ERROR incorrect braces around trait bounds
+
+fn foo3(_: &dyn {Drop + AsRef<str>}) {} //~ ERROR expected parameter name, found `{`
+//~^ ERROR expected one of `!`, `(`, `)`, `,`, `?`, `for`, lifetime, or path, found `{`
+//~| ERROR at least one trait is required for an object type
+
+fn foo4(_: &dyn <Drop + AsRef<str>>) {} //~ ERROR expected identifier, found `<`
+
+fn foo5(_: &(dyn Drop + dyn AsRef<str>)) {} //~ ERROR invalid `dyn` keyword
+//~^ ERROR only auto traits can be used as additional traits in a trait object
+
+fn main() {}
diff --git a/src/test/ui/parser/trait-object-delimiters.stderr b/src/test/ui/parser/trait-object-delimiters.stderr
new file mode 100644
index 0000000000000..18b1b24122ecf
--- /dev/null
+++ b/src/test/ui/parser/trait-object-delimiters.stderr
@@ -0,0 +1,77 @@
+error: ambiguous `+` in a type
+  --> $DIR/trait-object-delimiters.rs:3:13
+   |
+LL | fn foo1(_: &dyn Drop + AsRef<str>) {}
+   |             ^^^^^^^^^^^^^^^^^^^^^ help: use parentheses to disambiguate: `(dyn Drop + AsRef<str>)`
+
+error: incorrect braces around trait bounds
+  --> $DIR/trait-object-delimiters.rs:6:17
+   |
+LL | fn foo2(_: &dyn (Drop + AsRef<str>)) {}
+   |                 ^                 ^
+   |
+help: remove the parentheses
+   |
+LL | fn foo2(_: &dyn Drop + AsRef<str>) {}
+   |                --               --
+
+error: expected parameter name, found `{`
+  --> $DIR/trait-object-delimiters.rs:8:17
+   |
+LL | fn foo3(_: &dyn {Drop + AsRef<str>}) {}
+   |                 ^ expected parameter name
+
+error: expected one of `!`, `(`, `)`, `,`, `?`, `for`, lifetime, or path, found `{`
+  --> $DIR/trait-object-delimiters.rs:8:17
+   |
+LL | fn foo3(_: &dyn {Drop + AsRef<str>}) {}
+   |                -^ expected one of 8 possible tokens
+   |                |
+   |                help: missing `,`
+
+error: expected identifier, found `<`
+  --> $DIR/trait-object-delimiters.rs:12:17
+   |
+LL | fn foo4(_: &dyn <Drop + AsRef<str>>) {}
+   |                 ^ expected identifier
+
+error: invalid `dyn` keyword
+  --> $DIR/trait-object-delimiters.rs:14:25
+   |
+LL | fn foo5(_: &(dyn Drop + dyn AsRef<str>)) {}
+   |                         ^^^ help: remove this keyword
+   |
+   = help: `dyn` is only needed at the start of a trait `+`-separated list
+
+error[E0225]: only auto traits can be used as additional traits in a trait object
+  --> $DIR/trait-object-delimiters.rs:3:24
+   |
+LL | fn foo1(_: &dyn Drop + AsRef<str>) {}
+   |                 ----   ^^^^^^^^^^ additional non-auto trait
+   |                 |
+   |                 first non-auto trait
+   |
+   = help: consider creating a new trait with all of these as super-traits and using that trait here instead: `trait NewTrait: Drop + AsRef<str> {}`
+   = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>
+
+error[E0224]: at least one trait is required for an object type
+  --> $DIR/trait-object-delimiters.rs:8:13
+   |
+LL | fn foo3(_: &dyn {Drop + AsRef<str>}) {}
+   |             ^^^
+
+error[E0225]: only auto traits can be used as additional traits in a trait object
+  --> $DIR/trait-object-delimiters.rs:14:29
+   |
+LL | fn foo5(_: &(dyn Drop + dyn AsRef<str>)) {}
+   |                  ----       ^^^^^^^^^^ additional non-auto trait
+   |                  |
+   |                  first non-auto trait
+   |
+   = help: consider creating a new trait with all of these as super-traits and using that trait here instead: `trait NewTrait: Drop + AsRef<str> {}`
+   = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>
+
+error: aborting due to 9 previous errors
+
+Some errors have detailed explanations: E0224, E0225.
+For more information about an error, try `rustc --explain E0224`.
diff --git a/src/test/ui/parser/unsafe-mod.stderr b/src/test/ui/parser/unsafe-mod.stderr
index 259b2c1d61e08..dac6e7a355056 100644
--- a/src/test/ui/parser/unsafe-mod.stderr
+++ b/src/test/ui/parser/unsafe-mod.stderr
@@ -4,7 +4,7 @@ error[E0583]: file not found for module `n`
 LL | unsafe mod n;
    | ^^^^^^^^^^^^^
    |
-   = help: to create the module `n`, create file "$DIR/n.rs"
+   = help: to create the module `n`, create file "$DIR/n.rs" or "$DIR/n/mod.rs"
 
 error: module cannot be declared unsafe
   --> $DIR/unsafe-mod.rs:1:1
diff --git a/src/test/ui/rfc-2457/mod_file_nonascii_forbidden.stderr b/src/test/ui/rfc-2457/mod_file_nonascii_forbidden.stderr
index e857a1e60e5fe..dd0dac95e3646 100644
--- a/src/test/ui/rfc-2457/mod_file_nonascii_forbidden.stderr
+++ b/src/test/ui/rfc-2457/mod_file_nonascii_forbidden.stderr
@@ -4,7 +4,7 @@ error[E0583]: file not found for module `řųśť`
 LL | mod řųśť;
    | ^^^^^^^^^
    |
-   = help: to create the module `řųśť`, create file "$DIR/řųśť.rs"
+   = help: to create the module `řųśť`, create file "$DIR/řųśť.rs" or "$DIR/řųśť/mod.rs"
 
 error[E0754]: trying to load file for module `řųśť` with non-ascii identifier name
   --> $DIR/mod_file_nonascii_forbidden.rs:1:5