From 1f2db3ddfcc1af86221bcffbcbc0ac789cabe89b Mon Sep 17 00:00:00 2001
From: Takashiidobe <idobetakashi@gmail.com>
Date: Fri, 16 Feb 2024 20:21:34 -0500
Subject: [PATCH 01/27] Add an example to demonstrate how Rc::into_inner works

---
 library/alloc/src/rc.rs | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/library/alloc/src/rc.rs b/library/alloc/src/rc.rs
index 2cc38d90ffe4d..5c408f573bfe8 100644
--- a/library/alloc/src/rc.rs
+++ b/library/alloc/src/rc.rs
@@ -944,6 +944,21 @@ impl<T, A: Allocator> Rc<T, A> {
     /// is in fact equivalent to <code>[Rc::try_unwrap]\(this).[ok][Result::ok]()</code>.
     /// (Note that the same kind of equivalence does **not** hold true for
     /// [`Arc`](crate::sync::Arc), due to race conditions that do not apply to `Rc`!)
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::rc::Rc;
+    ///
+    /// let x = Rc::new(3);
+    /// assert_eq!(Rc::into_inner(x), Some(3));
+    ///
+    /// let x = Rc::new(4);
+    /// let y = Rc::clone(&x);
+    ///
+    /// assert_eq!(Rc::into_inner(y), None);
+    /// assert_eq!(Rc::into_inner(x), Some(4));
+    /// ```
     #[inline]
     #[stable(feature = "rc_into_inner", since = "1.70.0")]
     pub fn into_inner(this: Self) -> Option<T> {

From cb8ce9d9e543ccf16a2f0a04e47a3691af10d5a6 Mon Sep 17 00:00:00 2001
From: Jacob Asper <jacobasper191@gmail.com>
Date: Fri, 16 Feb 2024 09:41:48 -0500
Subject: [PATCH 02/27] time complexity for push

---
 library/alloc/src/vec/mod.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index 08e3cdedc666b..7bdf92053f151 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -1912,6 +1912,13 @@ impl<T, A: Allocator> Vec<T, A> {
     /// vec.push(3);
     /// assert_eq!(vec, [1, 2, 3]);
     /// ```
+    ///
+    /// # Time complexity
+    ///
+    /// Takes amortized *O*(1) time. If the vector's length would exceed its capacity after
+    /// the push,*O*(*capacity*) space is allocated, doubling the capacity and
+    /// taking *O*(*capacity*) time. This expensive operation is offset by the
+    /// *capacity* *O*(1) insertions it allows.
     #[cfg(not(no_global_oom_handling))]
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]

From bb6dca0fc89d335e106151ee334fc18916f63067 Mon Sep 17 00:00:00 2001
From: Jacob Asper <jacobasper191@gmail.com>
Date: Fri, 16 Feb 2024 09:58:34 -0500
Subject: [PATCH 03/27] time complexity for push_within_capacity

---
 library/alloc/src/vec/mod.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index 7bdf92053f151..d6e2bd324004c 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -1966,6 +1966,10 @@ impl<T, A: Allocator> Vec<T, A> {
     /// }
     /// assert_eq!(from_iter_fallible(0..100), Ok(Vec::from_iter(0..100)));
     /// ```
+    ///
+    /// # Time complexity
+    ///
+    /// Takes *O*(1) time.
     #[inline]
     #[unstable(feature = "vec_push_within_capacity", issue = "100486")]
     pub fn push_within_capacity(&mut self, value: T) -> Result<(), T> {

From 0a5d6841e8b14b2a4430ed675d2621fdd6747d04 Mon Sep 17 00:00:00 2001
From: Jacob Asper <jacobasper191@gmail.com>
Date: Fri, 16 Feb 2024 09:59:37 -0500
Subject: [PATCH 04/27] time complexity for pop

---
 library/alloc/src/vec/mod.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index d6e2bd324004c..27efffb72ac04 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -1999,6 +1999,10 @@ impl<T, A: Allocator> Vec<T, A> {
     /// assert_eq!(vec.pop(), Some(3));
     /// assert_eq!(vec, [1, 2]);
     /// ```
+    ///
+    /// # Time complexity
+    ///
+    /// Takes *O*(1) time.
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn pop(&mut self) -> Option<T> {

From d2f825f26127f71cd853c602818452c8be876ea8 Mon Sep 17 00:00:00 2001
From: Jacob Asper <jacobasper191@gmail.com>
Date: Sun, 18 Feb 2024 05:14:17 -0500
Subject: [PATCH 05/27] time complexity for insert

---
 library/alloc/src/vec/mod.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index 27efffb72ac04..711b4a8a8ef35 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -1490,6 +1490,12 @@ impl<T, A: Allocator> Vec<T, A> {
     /// vec.insert(4, 5);
     /// assert_eq!(vec, [1, 4, 2, 3, 5]);
     /// ```
+    ///
+    /// # Time complexity
+    ///
+    /// Takes *O*(`len`) time. All items after the insertion index must be
+    /// shifted to the right. In the worst case, all elements are shifted when
+    /// the insertion index is 0.
     #[cfg(not(no_global_oom_handling))]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn insert(&mut self, index: usize, element: T) {

From ef1a58484286454af6815d7e8a2f52c10b1449f2 Mon Sep 17 00:00:00 2001
From: Jacob Asper <jacobasper191@gmail.com>
Date: Sun, 18 Feb 2024 05:29:56 -0500
Subject: [PATCH 06/27] intradoc link for vec

---
 library/alloc/src/vec/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index 711b4a8a8ef35..e9a57c0a47b6d 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -1493,7 +1493,7 @@ impl<T, A: Allocator> Vec<T, A> {
     ///
     /// # Time complexity
     ///
-    /// Takes *O*(`len`) time. All items after the insertion index must be
+    /// Takes *O*([`Vec::len`]) time. All items after the insertion index must be
     /// shifted to the right. In the worst case, all elements are shifted when
     /// the insertion index is 0.
     #[cfg(not(no_global_oom_handling))]

From a9cfeb34ddd4b859042f8d8f02ae96a0dbf8574b Mon Sep 17 00:00:00 2001
From: Jacob Asper <jacobasper191@gmail.com>
Date: Sun, 18 Feb 2024 06:02:05 -0500
Subject: [PATCH 07/27] fix typo in push documentation

---
 library/alloc/src/vec/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index e9a57c0a47b6d..b4eee69e31f77 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -1922,7 +1922,7 @@ impl<T, A: Allocator> Vec<T, A> {
     /// # Time complexity
     ///
     /// Takes amortized *O*(1) time. If the vector's length would exceed its capacity after
-    /// the push,*O*(*capacity*) space is allocated, doubling the capacity and
+    /// the push, *O*(*capacity*) space is allocated, doubling the capacity and
     /// taking *O*(*capacity*) time. This expensive operation is offset by the
     /// *capacity* *O*(1) insertions it allows.
     #[cfg(not(no_global_oom_handling))]

From bc52e5d4de4a41f41e9849e564c955ce3d1fe513 Mon Sep 17 00:00:00 2001
From: Jacob Asper <jacobasper191@gmail.com>
Date: Sun, 18 Feb 2024 17:55:52 -0500
Subject: [PATCH 08/27] Fix error in push docs
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Copying is O(n)—not the memory allocation
---
 library/alloc/src/vec/mod.rs | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index b4eee69e31f77..bd36b55d782fe 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -1921,10 +1921,11 @@ impl<T, A: Allocator> Vec<T, A> {
     ///
     /// # Time complexity
     ///
-    /// Takes amortized *O*(1) time. If the vector's length would exceed its capacity after
-    /// the push, *O*(*capacity*) space is allocated, doubling the capacity and
-    /// taking *O*(*capacity*) time. This expensive operation is offset by the
-    /// *capacity* *O*(1) insertions it allows.
+    /// Takes amortized *O*(1) time. If the vector's length would exceed its
+    /// capacity after the push, the capacity is doubled by allocating
+    /// *O*(*capacity*) space, then *O*(*capacity*) time to copy the vector's
+    /// elements. This expensive operation is offset by the *capacity* *O*(1)
+    /// insertions it allows.
     #[cfg(not(no_global_oom_handling))]
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]

From 261da5fc4b2f015436a206f217300f6616628052 Mon Sep 17 00:00:00 2001
From: Zachary S <zasample18+github@gmail.com>
Date: Sun, 18 Feb 2024 22:43:42 -0600
Subject: [PATCH 09/27] Clarify/add `must_use` message for
 Rc/Arc/Weak::into_raw.

---
 library/alloc/src/rc.rs   | 3 ++-
 library/alloc/src/sync.rs | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/library/alloc/src/rc.rs b/library/alloc/src/rc.rs
index 2cc38d90ffe4d..c6ce42e7aa76c 100644
--- a/library/alloc/src/rc.rs
+++ b/library/alloc/src/rc.rs
@@ -1329,6 +1329,7 @@ impl<T: ?Sized, A: Allocator> Rc<T, A> {
     /// let x_ptr = Rc::into_raw(x);
     /// assert_eq!(unsafe { &*x_ptr }, "hello");
     /// ```
+    #[must_use = "losing the pointer will leak memory"]
     #[stable(feature = "rc_raw", since = "1.17.0")]
     #[rustc_never_returns_null_ptr]
     pub fn into_raw(this: Self) -> *const T {
@@ -2966,7 +2967,7 @@ impl<T: ?Sized, A: Allocator> Weak<T, A> {
     ///
     /// [`from_raw`]: Weak::from_raw
     /// [`as_ptr`]: Weak::as_ptr
-    #[must_use = "`self` will be dropped if the result is not used"]
+    #[must_use = "losing the pointer will leak memory"]
     #[stable(feature = "weak_into_raw", since = "1.45.0")]
     pub fn into_raw(self) -> *const T {
         let result = self.as_ptr();
diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs
index e1211da4c6176..c7c38d9b45e94 100644
--- a/library/alloc/src/sync.rs
+++ b/library/alloc/src/sync.rs
@@ -2715,7 +2715,7 @@ impl<T: ?Sized, A: Allocator> Weak<T, A> {
     ///
     /// [`from_raw`]: Weak::from_raw
     /// [`as_ptr`]: Weak::as_ptr
-    #[must_use = "`self` will be dropped if the result is not used"]
+    #[must_use = "losing the pointer will leak memory"]
     #[stable(feature = "weak_into_raw", since = "1.45.0")]
     pub fn into_raw(self) -> *const T {
         let result = self.as_ptr();

From 74151cbbf04477b646c7fcfd1db60f9c79c06081 Mon Sep 17 00:00:00 2001
From: Jacob Asper <jacobasper191@gmail.com>
Date: Sun, 25 Feb 2024 02:41:54 -0500
Subject: [PATCH 10/27] Make push docs more vague

---
 library/alloc/src/vec/mod.rs | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index bd36b55d782fe..aaac911175d7f 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -1922,10 +1922,9 @@ impl<T, A: Allocator> Vec<T, A> {
     /// # Time complexity
     ///
     /// Takes amortized *O*(1) time. If the vector's length would exceed its
-    /// capacity after the push, the capacity is doubled by allocating
-    /// *O*(*capacity*) space, then *O*(*capacity*) time to copy the vector's
-    /// elements. This expensive operation is offset by the *capacity* *O*(1)
-    /// insertions it allows.
+    /// capacity after the push, *O*(*capacity*) time is taken to copy the
+    /// vector's elements to a larger allocation. This expensive operation is
+    /// offset by the *capacity* *O*(1) insertions it allows.
     #[cfg(not(no_global_oom_handling))]
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]

From e0a726ca4bc08d1009803a6c819f701173810761 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Tue, 27 Feb 2024 03:14:55 +0000
Subject: [PATCH 11/27] Adjust error yield/await lowering

---
 compiler/rustc_ast_lowering/src/expr.rs       | 52 +++++++++++++++----
 .../async-outside-of-await-issue-121096.rs    |  9 ++++
 ...async-outside-of-await-issue-121096.stderr | 12 +++++
 3 files changed, 64 insertions(+), 9 deletions(-)
 create mode 100644 tests/ui/async-await/async-outside-of-await-issue-121096.rs
 create mode 100644 tests/ui/async-await/async-outside-of-await-issue-121096.stderr

diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs
index 9950db4784b9c..599b7ca0af671 100644
--- a/compiler/rustc_ast_lowering/src/expr.rs
+++ b/compiler/rustc_ast_lowering/src/expr.rs
@@ -764,10 +764,28 @@ impl<'hir> LoweringContext<'_, 'hir> {
             Some(hir::CoroutineKind::Coroutine(_))
             | Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _))
             | None => {
-                return hir::ExprKind::Err(self.dcx().emit_err(AwaitOnlyInAsyncFnAndBlocks {
-                    await_kw_span,
-                    item_span: self.current_item,
-                }));
+                // Lower to a block `{ EXPR; <error> }` so that the awaited expr
+                // is not accidentally orphaned.
+                let stmt_id = self.next_id();
+                let expr_err = self.expr(
+                    expr.span,
+                    hir::ExprKind::Err(self.dcx().emit_err(AwaitOnlyInAsyncFnAndBlocks {
+                        await_kw_span,
+                        item_span: self.current_item,
+                    })),
+                );
+                return hir::ExprKind::Block(
+                    self.block_all(
+                        expr.span,
+                        arena_vec![self; hir::Stmt {
+                            hir_id: stmt_id,
+                            kind: hir::StmtKind::Semi(expr),
+                            span: expr.span,
+                        }],
+                        Some(self.arena.alloc(expr_err)),
+                    ),
+                    None,
+                );
             }
         };
 
@@ -1500,12 +1518,31 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     fn lower_expr_yield(&mut self, span: Span, opt_expr: Option<&Expr>) -> hir::ExprKind<'hir> {
+        let yielded =
+            opt_expr.as_ref().map(|x| self.lower_expr(x)).unwrap_or_else(|| self.expr_unit(span));
+
         let is_async_gen = match self.coroutine_kind {
             Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _)) => false,
             Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _)) => true,
             Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)) => {
-                return hir::ExprKind::Err(
-                    self.dcx().emit_err(AsyncCoroutinesNotSupported { span }),
+                // Lower to a block `{ EXPR; <error> }` so that the awaited expr
+                // is not accidentally orphaned.
+                let stmt_id = self.next_id();
+                let expr_err = self.expr(
+                    yielded.span,
+                    hir::ExprKind::Err(self.dcx().emit_err(AsyncCoroutinesNotSupported { span })),
+                );
+                return hir::ExprKind::Block(
+                    self.block_all(
+                        yielded.span,
+                        arena_vec![self; hir::Stmt {
+                            hir_id: stmt_id,
+                            kind: hir::StmtKind::Semi(yielded),
+                            span: yielded.span,
+                        }],
+                        Some(self.arena.alloc(expr_err)),
+                    ),
+                    None,
                 );
             }
             Some(hir::CoroutineKind::Coroutine(_)) => {
@@ -1535,9 +1572,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
             }
         };
 
-        let yielded =
-            opt_expr.as_ref().map(|x| self.lower_expr(x)).unwrap_or_else(|| self.expr_unit(span));
-
         if is_async_gen {
             // `yield $expr` is transformed into `task_context = yield async_gen_ready($expr)`.
             // This ensures that we store our resumed `ResumeContext` correctly, and also that
diff --git a/tests/ui/async-await/async-outside-of-await-issue-121096.rs b/tests/ui/async-await/async-outside-of-await-issue-121096.rs
new file mode 100644
index 0000000000000..e3999035ef91f
--- /dev/null
+++ b/tests/ui/async-await/async-outside-of-await-issue-121096.rs
@@ -0,0 +1,9 @@
+//@ edition:2021
+
+fn main() {
+    async {
+        use std::ops::Add;
+        let _ = 1.add(3);
+    }.await
+    //~^ ERROR `await` is only allowed inside `async` functions and blocks
+}
diff --git a/tests/ui/async-await/async-outside-of-await-issue-121096.stderr b/tests/ui/async-await/async-outside-of-await-issue-121096.stderr
new file mode 100644
index 0000000000000..b0677a83864e0
--- /dev/null
+++ b/tests/ui/async-await/async-outside-of-await-issue-121096.stderr
@@ -0,0 +1,12 @@
+error[E0728]: `await` is only allowed inside `async` functions and blocks
+  --> $DIR/async-outside-of-await-issue-121096.rs:7:7
+   |
+LL | fn main() {
+   |    ---- this is not `async`
+...
+LL |     }.await
+   |       ^^^^^ only allowed inside `async` functions and blocks
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0728`.

From 91322f4e702799dd9275a5cdd87d30b787cfc619 Mon Sep 17 00:00:00 2001
From: Urgau <urgau@numericable.fr>
Date: Fri, 16 Feb 2024 21:32:53 +0100
Subject: [PATCH 12/27] Limit the number of names and values in check-cfg
 diagnostics

---
 .../rustc_lint/src/context/diagnostics.rs     | 71 +++++++++++++------
 compiler/rustc_session/src/options.rs         |  2 +
 tests/ui/check-cfg/mix.rs                     |  2 +
 tests/ui/check-cfg/mix.stderr                 | 11 ++-
 tests/ui/check-cfg/well-known-values.rs       |  1 +
 tests/ui/check-cfg/well-known-values.stderr   | 54 +++++++-------
 6 files changed, 93 insertions(+), 48 deletions(-)

diff --git a/compiler/rustc_lint/src/context/diagnostics.rs b/compiler/rustc_lint/src/context/diagnostics.rs
index 71aef50391d5b..1bdf95d7e478a 100644
--- a/compiler/rustc_lint/src/context/diagnostics.rs
+++ b/compiler/rustc_lint/src/context/diagnostics.rs
@@ -12,6 +12,43 @@ use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::BytePos;
 
+const MAX_CHECK_CFG_NAMES_OR_VALUES: usize = 35;
+
+fn check_cfg_expected_note(
+    sess: &Session,
+    possibilities: &[Symbol],
+    type_: &str,
+    name: Option<Symbol>,
+    suffix: &str,
+) -> String {
+    use std::fmt::Write;
+
+    let n_possibilities = if sess.opts.unstable_opts.check_cfg_all_expected {
+        possibilities.len()
+    } else {
+        std::cmp::min(possibilities.len(), MAX_CHECK_CFG_NAMES_OR_VALUES)
+    };
+
+    let mut possibilities = possibilities.iter().map(Symbol::as_str).collect::<Vec<_>>();
+    possibilities.sort();
+
+    let and_more = possibilities.len().saturating_sub(n_possibilities);
+    let possibilities = possibilities[..n_possibilities].join("`, `");
+
+    let mut note = String::with_capacity(50 + possibilities.len());
+
+    write!(&mut note, "expected {type_}").unwrap();
+    if let Some(name) = name {
+        write!(&mut note, " for `{name}`").unwrap();
+    }
+    write!(&mut note, " are: {suffix}`{possibilities}`").unwrap();
+    if and_more > 0 {
+        write!(&mut note, " and {and_more} more").unwrap();
+    }
+
+    note
+}
+
 pub(super) fn builtin(sess: &Session, diagnostic: BuiltinLintDiagnostics, diag: &mut Diag<'_, ()>) {
     match diagnostic {
         BuiltinLintDiagnostics::UnicodeTextFlow(span, content) => {
@@ -291,16 +328,13 @@ pub(super) fn builtin(sess: &Session, diagnostic: BuiltinLintDiagnostics, diag:
                     }
                 }
                 if !possibilities.is_empty() {
-                    let mut possibilities =
-                        possibilities.iter().map(Symbol::as_str).collect::<Vec<_>>();
-                    possibilities.sort();
-                    let possibilities = possibilities.join("`, `");
-
-                    // The list of expected names can be long (even by default) and
-                    // so the diagnostic produced can take a lot of space. To avoid
-                    // cloging the user output we only want to print that diagnostic
-                    // once.
-                    diag.help_once(format!("expected names are: `{possibilities}`"));
+                    diag.help_once(check_cfg_expected_note(
+                        sess,
+                        &possibilities,
+                        "names",
+                        None,
+                        "",
+                    ));
                 }
             }
 
@@ -344,16 +378,13 @@ pub(super) fn builtin(sess: &Session, diagnostic: BuiltinLintDiagnostics, diag:
             // Show the full list if all possible values for a given name, but don't do it
             // for names as the possibilities could be very long
             if !possibilities.is_empty() {
-                {
-                    let mut possibilities =
-                        possibilities.iter().map(Symbol::as_str).collect::<Vec<_>>();
-                    possibilities.sort();
-
-                    let possibilities = possibilities.join("`, `");
-                    let none = if have_none_possibility { "(none), " } else { "" };
-
-                    diag.note(format!("expected values for `{name}` are: {none}`{possibilities}`"));
-                }
+                diag.note(check_cfg_expected_note(
+                    sess,
+                    &possibilities,
+                    "values",
+                    Some(name),
+                    if have_none_possibility { "(none), " } else { "" },
+                ));
 
                 if let Some((value, value_span)) = value {
                     // Suggest the most probable if we found one
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index 743f476033935..f4b910d62a723 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -1551,6 +1551,8 @@ options! {
         "set options for branch target identification and pointer authentication on AArch64"),
     cf_protection: CFProtection = (CFProtection::None, parse_cfprotection, [TRACKED],
         "instrument control-flow architecture protection"),
+    check_cfg_all_expected: bool = (false, parse_bool, [UNTRACKED],
+        "show all expected values in check-cfg diagnostics (default: no)"),
     codegen_backend: Option<String> = (None, parse_opt_string, [TRACKED],
         "the backend to use"),
     collapse_macro_debuginfo: CollapseMacroDebuginfo = (CollapseMacroDebuginfo::Unspecified,
diff --git a/tests/ui/check-cfg/mix.rs b/tests/ui/check-cfg/mix.rs
index ba30bc1e69b50..69156ab67635e 100644
--- a/tests/ui/check-cfg/mix.rs
+++ b/tests/ui/check-cfg/mix.rs
@@ -74,6 +74,8 @@ fn test_cfg_macro() {
     //~^ WARNING unexpected `cfg` condition value
     //~| WARNING unexpected `cfg` condition value
     //~| WARNING unexpected `cfg` condition value
+    cfg!(target_feature = "zebra");
+    //~^ WARNING unexpected `cfg` condition value
 }
 
 fn main() {}
diff --git a/tests/ui/check-cfg/mix.stderr b/tests/ui/check-cfg/mix.stderr
index 77643f227d9d0..93333e5ef2a5b 100644
--- a/tests/ui/check-cfg/mix.stderr
+++ b/tests/ui/check-cfg/mix.stderr
@@ -245,5 +245,14 @@ LL |     cfg!(all(feature = "zebra", feature = "zebra", feature = "zebra"));
    = help: to expect this configuration use `--check-cfg=cfg(feature, values("zebra"))`
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
-warning: 26 warnings emitted
+warning: unexpected `cfg` condition value: `zebra`
+  --> $DIR/mix.rs:77:10
+   |
+LL |     cfg!(target_feature = "zebra");
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: expected values for `target_feature` are: `10e60`, `2e3`, `3e3r1`, `3e3r2`, `3e3r3`, `3e7`, `7e10`, `a`, `aclass`, `adx`, `aes`, `altivec`, `alu32`, `atomics`, `avx`, `avx2`, `avx512bf16`, `avx512bitalg`, `avx512bw`, `avx512cd`, `avx512dq`, `avx512er`, `avx512f`, `avx512fp16`, `avx512ifma`, `avx512pf`, `avx512vbmi`, `avx512vbmi2`, `avx512vl`, `avx512vnni`, `avx512vp2intersect`, `avx512vpopcntdq`, `bf16`, `bmi1`, `bmi2` and 186 more
+   = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
+
+warning: 27 warnings emitted
 
diff --git a/tests/ui/check-cfg/well-known-values.rs b/tests/ui/check-cfg/well-known-values.rs
index 859a36c604c6f..fa062a3fe2eae 100644
--- a/tests/ui/check-cfg/well-known-values.rs
+++ b/tests/ui/check-cfg/well-known-values.rs
@@ -6,6 +6,7 @@
 //
 //@ check-pass
 //@ compile-flags: --check-cfg=cfg() -Z unstable-options
+//@ compile-flags: -Zcheck-cfg-all-expected
 
 #![feature(cfg_overflow_checks)]
 #![feature(cfg_relocation_model)]
diff --git a/tests/ui/check-cfg/well-known-values.stderr b/tests/ui/check-cfg/well-known-values.stderr
index 5dda4931d543a..ba3fbd5c23515 100644
--- a/tests/ui/check-cfg/well-known-values.stderr
+++ b/tests/ui/check-cfg/well-known-values.stderr
@@ -1,5 +1,5 @@
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:25:5
+  --> $DIR/well-known-values.rs:26:5
    |
 LL |     clippy = "_UNEXPECTED_VALUE",
    |     ^^^^^^----------------------
@@ -11,7 +11,7 @@ LL |     clippy = "_UNEXPECTED_VALUE",
    = note: `#[warn(unexpected_cfgs)]` on by default
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:27:5
+  --> $DIR/well-known-values.rs:28:5
    |
 LL |     debug_assertions = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^----------------------
@@ -22,7 +22,7 @@ LL |     debug_assertions = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:29:5
+  --> $DIR/well-known-values.rs:30:5
    |
 LL |     doc = "_UNEXPECTED_VALUE",
    |     ^^^----------------------
@@ -33,7 +33,7 @@ LL |     doc = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:31:5
+  --> $DIR/well-known-values.rs:32:5
    |
 LL |     doctest = "_UNEXPECTED_VALUE",
    |     ^^^^^^^----------------------
@@ -44,7 +44,7 @@ LL |     doctest = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:33:5
+  --> $DIR/well-known-values.rs:34:5
    |
 LL |     miri = "_UNEXPECTED_VALUE",
    |     ^^^^----------------------
@@ -55,7 +55,7 @@ LL |     miri = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:35:5
+  --> $DIR/well-known-values.rs:36:5
    |
 LL |     overflow_checks = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^----------------------
@@ -66,7 +66,7 @@ LL |     overflow_checks = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:37:5
+  --> $DIR/well-known-values.rs:38:5
    |
 LL |     panic = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -75,7 +75,7 @@ LL |     panic = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:39:5
+  --> $DIR/well-known-values.rs:40:5
    |
 LL |     proc_macro = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^----------------------
@@ -86,7 +86,7 @@ LL |     proc_macro = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:41:5
+  --> $DIR/well-known-values.rs:42:5
    |
 LL |     relocation_model = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -95,7 +95,7 @@ LL |     relocation_model = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:43:5
+  --> $DIR/well-known-values.rs:44:5
    |
 LL |     sanitize = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -104,7 +104,7 @@ LL |     sanitize = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:45:5
+  --> $DIR/well-known-values.rs:46:5
    |
 LL |     target_abi = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -113,7 +113,7 @@ LL |     target_abi = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:47:5
+  --> $DIR/well-known-values.rs:48:5
    |
 LL |     target_arch = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -122,7 +122,7 @@ LL |     target_arch = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:49:5
+  --> $DIR/well-known-values.rs:50:5
    |
 LL |     target_endian = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -131,7 +131,7 @@ LL |     target_endian = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:51:5
+  --> $DIR/well-known-values.rs:52:5
    |
 LL |     target_env = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -140,7 +140,7 @@ LL |     target_env = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:53:5
+  --> $DIR/well-known-values.rs:54:5
    |
 LL |     target_family = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -149,7 +149,7 @@ LL |     target_family = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:55:5
+  --> $DIR/well-known-values.rs:56:5
    |
 LL |     target_feature = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -158,7 +158,7 @@ LL |     target_feature = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:57:5
+  --> $DIR/well-known-values.rs:58:5
    |
 LL |     target_has_atomic = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -167,7 +167,7 @@ LL |     target_has_atomic = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:59:5
+  --> $DIR/well-known-values.rs:60:5
    |
 LL |     target_has_atomic_equal_alignment = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -176,7 +176,7 @@ LL |     target_has_atomic_equal_alignment = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:61:5
+  --> $DIR/well-known-values.rs:62:5
    |
 LL |     target_has_atomic_load_store = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -185,7 +185,7 @@ LL |     target_has_atomic_load_store = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:63:5
+  --> $DIR/well-known-values.rs:64:5
    |
 LL |     target_os = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -194,7 +194,7 @@ LL |     target_os = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:65:5
+  --> $DIR/well-known-values.rs:66:5
    |
 LL |     target_pointer_width = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -203,7 +203,7 @@ LL |     target_pointer_width = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:67:5
+  --> $DIR/well-known-values.rs:68:5
    |
 LL |     target_thread_local = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^----------------------
@@ -214,7 +214,7 @@ LL |     target_thread_local = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:69:5
+  --> $DIR/well-known-values.rs:70:5
    |
 LL |     target_vendor = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -223,7 +223,7 @@ LL |     target_vendor = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:71:5
+  --> $DIR/well-known-values.rs:72:5
    |
 LL |     test = "_UNEXPECTED_VALUE",
    |     ^^^^----------------------
@@ -234,7 +234,7 @@ LL |     test = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:73:5
+  --> $DIR/well-known-values.rs:74:5
    |
 LL |     unix = "_UNEXPECTED_VALUE",
    |     ^^^^----------------------
@@ -245,7 +245,7 @@ LL |     unix = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
-  --> $DIR/well-known-values.rs:75:5
+  --> $DIR/well-known-values.rs:76:5
    |
 LL |     windows = "_UNEXPECTED_VALUE",
    |     ^^^^^^^----------------------
@@ -256,7 +256,7 @@ LL |     windows = "_UNEXPECTED_VALUE",
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `linuz`
-  --> $DIR/well-known-values.rs:81:7
+  --> $DIR/well-known-values.rs:82:7
    |
 LL | #[cfg(target_os = "linuz")] // testing that we suggest `linux`
    |       ^^^^^^^^^^^^-------

From f5f11e11978a57f25c27b670d2e8b2b001fc9d01 Mon Sep 17 00:00:00 2001
From: Oli Scherer <git-spam-no-reply9815368754983@oli-obk.de>
Date: Fri, 1 Mar 2024 08:47:31 +0000
Subject: [PATCH 13/27] Add regression test

---
 .../hidden_behind_struct_field3.rs            | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.rs

diff --git a/tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.rs b/tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.rs
new file mode 100644
index 0000000000000..366767929e4ba
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.rs
@@ -0,0 +1,28 @@
+//! This test demonstrates a bug where we accidentally
+//! detected opaque types in struct fields, but only if nested
+//! in projections of another opaque type.
+//@ check-pass
+
+#![feature(impl_trait_in_assoc_type)]
+
+struct Bar;
+
+trait Trait: Sized {
+    type Assoc2;
+    type Assoc;
+    fn foo() -> Self::Assoc;
+}
+
+impl Trait for Bar {
+    type Assoc2 = impl std::fmt::Debug;
+    type Assoc = impl Iterator<Item = Foo>;
+    fn foo() -> Self::Assoc {
+        vec![Foo { field: () }].into_iter()
+    }
+}
+
+struct Foo {
+    field: <Bar as Trait>::Assoc2,
+}
+
+fn main() {}

From c3954b358f9e2be96d0dd553a8efaefc49f0bba7 Mon Sep 17 00:00:00 2001
From: r0cky <mu001999@outlook.com>
Date: Sun, 3 Mar 2024 00:57:37 +0800
Subject: [PATCH 14/27] Add a tidy check that checks whether the fluent slugs
 only appear once

---
 src/tools/tidy/src/fluent_alphabetical.rs | 58 ++++++++++++++++++++---
 src/tools/tidy/src/fluent_used.rs         | 43 +++++++++++++++++
 src/tools/tidy/src/lib.rs                 |  1 +
 3 files changed, 96 insertions(+), 6 deletions(-)
 create mode 100644 src/tools/tidy/src/fluent_used.rs

diff --git a/src/tools/tidy/src/fluent_alphabetical.rs b/src/tools/tidy/src/fluent_alphabetical.rs
index 67b745373f019..9803b6eab2db5 100644
--- a/src/tools/tidy/src/fluent_alphabetical.rs
+++ b/src/tools/tidy/src/fluent_alphabetical.rs
@@ -1,6 +1,7 @@
 //! Checks that all Flunt files have messages in alphabetical order
 
 use crate::walk::{filter_dirs, walk};
+use std::collections::HashMap;
 use std::{fs::OpenOptions, io::Write, path::Path};
 
 use regex::Regex;
@@ -13,11 +14,27 @@ fn filter_fluent(path: &Path) -> bool {
     if let Some(ext) = path.extension() { ext.to_str() != Some("ftl") } else { true }
 }
 
-fn check_alphabetic(filename: &str, fluent: &str, bad: &mut bool) {
+fn check_alphabetic(
+    filename: &str,
+    fluent: &str,
+    bad: &mut bool,
+    all_defined_msgs: &mut HashMap<String, String>,
+) {
     let mut matches = MESSAGE.captures_iter(fluent).peekable();
     while let Some(m) = matches.next() {
+        let name = m.get(1).unwrap();
+        if let Some(defined_filename) = all_defined_msgs.get(name.as_str()) {
+            tidy_error!(
+                bad,
+                "{filename}: message `{}` is already defined in {}",
+                name.as_str(),
+                defined_filename,
+            );
+        }
+
+        all_defined_msgs.insert(name.as_str().to_owned(), filename.to_owned());
+
         if let Some(next) = matches.peek() {
-            let name = m.get(1).unwrap();
             let next = next.get(1).unwrap();
             if name.as_str() > next.as_str() {
                 tidy_error!(
@@ -34,13 +51,29 @@ run `./x.py test tidy --bless` to sort the file correctly",
     }
 }
 
-fn sort_messages(fluent: &str) -> String {
+fn sort_messages(
+    filename: &str,
+    fluent: &str,
+    bad: &mut bool,
+    all_defined_msgs: &mut HashMap<String, String>,
+) -> String {
     let mut chunks = vec![];
     let mut cur = String::new();
     for line in fluent.lines() {
-        if MESSAGE.is_match(line) {
+        if let Some(name) = MESSAGE.find(line) {
+            if let Some(defined_filename) = all_defined_msgs.get(name.as_str()) {
+                tidy_error!(
+                    bad,
+                    "{filename}: message `{}` is already defined in {}",
+                    name.as_str(),
+                    defined_filename,
+                );
+            }
+
+            all_defined_msgs.insert(name.as_str().to_owned(), filename.to_owned());
             chunks.push(std::mem::take(&mut cur));
         }
+
         cur += line;
         cur.push('\n');
     }
@@ -53,20 +86,33 @@ fn sort_messages(fluent: &str) -> String {
 }
 
 pub fn check(path: &Path, bless: bool, bad: &mut bool) {
+    let mut all_defined_msgs = HashMap::new();
     walk(
         path,
         |path, is_dir| filter_dirs(path) || (!is_dir && filter_fluent(path)),
         &mut |ent, contents| {
             if bless {
-                let sorted = sort_messages(contents);
+                let sorted = sort_messages(
+                    ent.path().to_str().unwrap(),
+                    contents,
+                    bad,
+                    &mut all_defined_msgs,
+                );
                 if sorted != contents {
                     let mut f =
                         OpenOptions::new().write(true).truncate(true).open(ent.path()).unwrap();
                     f.write(sorted.as_bytes()).unwrap();
                 }
             } else {
-                check_alphabetic(ent.path().to_str().unwrap(), contents, bad);
+                check_alphabetic(
+                    ent.path().to_str().unwrap(),
+                    contents,
+                    bad,
+                    &mut all_defined_msgs,
+                );
             }
         },
     );
+
+    crate::fluent_used::check(path, all_defined_msgs, bad);
 }
diff --git a/src/tools/tidy/src/fluent_used.rs b/src/tools/tidy/src/fluent_used.rs
new file mode 100644
index 0000000000000..b73e79cb38d94
--- /dev/null
+++ b/src/tools/tidy/src/fluent_used.rs
@@ -0,0 +1,43 @@
+//! Checks that all Fluent messages appear at least twice
+
+use crate::walk::{filter_dirs, walk};
+use regex::Regex;
+use std::collections::HashMap;
+use std::path::Path;
+
+lazy_static::lazy_static! {
+    static ref WORD: Regex = Regex::new(r"\w+").unwrap();
+}
+
+fn filter_used_messages(
+    contents: &str,
+    msgs_not_appeared_yet: &mut HashMap<String, String>,
+    msgs_appeared_only_once: &mut HashMap<String, String>,
+) {
+    // we don't just check messages never appear in Rust files,
+    // because messages can be used as parts of other fluent messages in Fluent files,
+    // so we do checking messages appear only once in all Rust and Fluent files.
+    let mut matches = WORD.find_iter(contents);
+    while let Some(name) = matches.next() {
+        if let Some((name, filename)) = msgs_not_appeared_yet.remove_entry(name.as_str()) {
+            // if one msg appears for the first time,
+            // remove it from `msgs_not_appeared_yet` and insert it into `msgs_appeared_only_once`.
+            msgs_appeared_only_once.insert(name, filename);
+        } else {
+            // if one msg appears for the second time,
+            // remove it from `msgs_appeared_only_once`.
+            msgs_appeared_only_once.remove(name.as_str());
+        }
+    }
+}
+
+pub fn check(path: &Path, mut all_defined_msgs: HashMap<String, String>, bad: &mut bool) {
+    let mut msgs_appear_only_once = HashMap::new();
+    walk(path, |path, _| filter_dirs(path), &mut |_, contents| {
+        filter_used_messages(contents, &mut all_defined_msgs, &mut msgs_appear_only_once);
+    });
+
+    for (name, filename) in msgs_appear_only_once {
+        tidy_error!(bad, "{filename}: message `{}` is not used", name,);
+    }
+}
diff --git a/src/tools/tidy/src/lib.rs b/src/tools/tidy/src/lib.rs
index 6f3ade0ab58c7..670b7eb2be995 100644
--- a/src/tools/tidy/src/lib.rs
+++ b/src/tools/tidy/src/lib.rs
@@ -65,6 +65,7 @@ pub mod ext_tool_checks;
 pub mod extdeps;
 pub mod features;
 pub mod fluent_alphabetical;
+mod fluent_used;
 pub(crate) mod iter_header;
 pub mod mir_opt_tests;
 pub mod pal;

From d88c7ffc62d0f1ee15abf3e9e65af3eeedc7d003 Mon Sep 17 00:00:00 2001
From: r0cky <mu001999@outlook.com>
Date: Sun, 3 Mar 2024 00:57:45 +0800
Subject: [PATCH 15/27] Remove unused fluent messages

---
 compiler/rustc_const_eval/messages.ftl | 3 ---
 compiler/rustc_infer/messages.ftl      | 8 --------
 compiler/rustc_lint/messages.ftl       | 2 --
 compiler/rustc_parse/messages.ftl      | 4 ----
 compiler/rustc_passes/messages.ftl     | 5 -----
 5 files changed, 22 deletions(-)

diff --git a/compiler/rustc_const_eval/messages.ftl b/compiler/rustc_const_eval/messages.ftl
index 2805ca360ad3d..1bad62c4103a3 100644
--- a/compiler/rustc_const_eval/messages.ftl
+++ b/compiler/rustc_const_eval/messages.ftl
@@ -146,9 +146,6 @@ const_eval_intern_kind = {$kind ->
     *[other] {""}
 }
 
-const_eval_invalid_align =
-    align has to be a power of 2
-
 const_eval_invalid_align_details =
     invalid align passed to `{$name}`: {$align} is {$err_kind ->
         [not_power_of_two] not a power of 2
diff --git a/compiler/rustc_infer/messages.ftl b/compiler/rustc_infer/messages.ftl
index 2de87cbe631ac..e44a6ae3b3f2e 100644
--- a/compiler/rustc_infer/messages.ftl
+++ b/compiler/rustc_infer/messages.ftl
@@ -181,14 +181,6 @@ infer_more_targeted = {$has_param_name ->
 
 infer_msl_introduces_static = introduces a `'static` lifetime requirement
 infer_msl_unmet_req = because this has an unmet lifetime requirement
-infer_need_type_info_in_coroutine =
-    type inside {$coroutine_kind ->
-    [async_block] `async` block
-    [async_closure] `async` closure
-    [async_fn] `async fn` body
-    *[coroutine] coroutine
-    } must be known in this context
-
 
 infer_nothing = {""}
 
diff --git a/compiler/rustc_lint/messages.ftl b/compiler/rustc_lint/messages.ftl
index 63e2fe47659db..8bf9d0b9d4aac 100644
--- a/compiler/rustc_lint/messages.ftl
+++ b/compiler/rustc_lint/messages.ftl
@@ -562,8 +562,6 @@ lint_suspicious_double_ref_clone =
 lint_suspicious_double_ref_deref =
     using `.deref()` on a double reference, which returns `{$ty}` instead of dereferencing the inner type
 
-lint_trivial_untranslatable_diag = diagnostic with static strings only
-
 lint_ty_qualified = usage of qualified `ty::{$ty}`
     .suggestion = try importing it and using it unqualified
 
diff --git a/compiler/rustc_parse/messages.ftl b/compiler/rustc_parse/messages.ftl
index 60cc138fd7bc2..a100e2d47bbbb 100644
--- a/compiler/rustc_parse/messages.ftl
+++ b/compiler/rustc_parse/messages.ftl
@@ -392,9 +392,6 @@ parse_invalid_identifier_with_leading_number = identifiers cannot start with a n
 
 parse_invalid_interpolated_expression = invalid interpolated expression
 
-parse_invalid_literal_suffix = suffixes on {$kind} literals are invalid
-    .label = invalid suffix `{$suffix}`
-
 parse_invalid_literal_suffix_on_tuple_index = suffixes on a tuple index are invalid
     .label = invalid suffix `{$suffix}`
     .tuple_exception_line_1 = `{$suffix}` is *temporarily* accepted on tuple index fields as it was incorrectly accepted on stable for a few releases
@@ -609,7 +606,6 @@ parse_nonterminal_expected_item_keyword = expected an item keyword
 parse_nonterminal_expected_lifetime = expected a lifetime, found `{$token}`
 
 parse_nonterminal_expected_statement = expected a statement
-parse_not_supported = not supported
 
 parse_note_edition_guide = for more on editions, read https://doc.rust-lang.org/edition-guide
 
diff --git a/compiler/rustc_passes/messages.ftl b/compiler/rustc_passes/messages.ftl
index c223b8475288b..7fc523ffe0dea 100644
--- a/compiler/rustc_passes/messages.ftl
+++ b/compiler/rustc_passes/messages.ftl
@@ -302,9 +302,6 @@ passes_export_name =
     attribute should be applied to a free function, impl method or static
     .label = not a free function, impl method or static
 
-passes_expr_not_allowed_in_context =
-    {$expr} is not allowed in a `{$context}`
-
 passes_extern_main =
     the `main` function cannot be declared in an `extern` block
 
@@ -405,8 +402,6 @@ passes_lang_item_on_incorrect_target =
     `{$name}` language item must be applied to a {$expected_target}
     .label = attribute should be applied to a {$expected_target}, not a {$actual_target}
 
-passes_layout =
-    layout error: {$layout_error}
 passes_layout_abi =
     abi: {$abi}
 passes_layout_align =

From dd0004a1296c02c67318b14734a8336f13875ae8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20K=C3=A5re=20Alsaker?= <john.kare.alsaker@gmail.com>
Date: Wed, 16 Aug 2023 17:50:40 +0200
Subject: [PATCH 16/27] Don't panic when waiting on poisoned queries

---
 compiler/rustc_query_system/src/query/plumbing.rs | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/compiler/rustc_query_system/src/query/plumbing.rs b/compiler/rustc_query_system/src/query/plumbing.rs
index 40517407ee6a1..3d9848395a20b 100644
--- a/compiler/rustc_query_system/src/query/plumbing.rs
+++ b/compiler/rustc_query_system/src/query/plumbing.rs
@@ -285,9 +285,8 @@ where
                     let lock = query.query_state(qcx).active.get_shard_by_value(&key).lock();
 
                     match lock.get(&key) {
-                        Some(QueryResult::Poisoned) => {
-                            panic!("query '{}' not cached due to poisoning", query.name())
-                        }
+                        // The query we waited on panicked. Continue unwinding here.
+                        Some(QueryResult::Poisoned) => FatalError.raise(),
                         _ => panic!(
                             "query '{}' result must be in the cache or the query must be poisoned after a wait",
                             query.name()

From a9a979839bbdfec48c75d618ab0dce8a953589b8 Mon Sep 17 00:00:00 2001
From: Sundeep KOKKONDA <56015745+sundeep-kokkonda@users.noreply.github.com>
Date: Mon, 4 Mar 2024 08:18:54 +0530
Subject: [PATCH 17/27] Removing absolute path in proc-macro

With rust 1.75 the absolute build path is embedding into '.rustc' section and which causes reproducibility issues. Detailed issue is here.
https://github.com/rust-lang/rust/issues/120825#issuecomment-1964307219

With this change the 'absolute path' changed back to '/rust/$hash' format.
---
 compiler/rustc_session/src/session.rs | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index 09fb6aa5d8f98..6a76d78b33f3d 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -898,19 +898,6 @@ impl Session {
     }
 
     pub fn should_prefer_remapped_for_codegen(&self) -> bool {
-        // bail out, if any of the requested crate types aren't:
-        // "compiled executables or libraries"
-        for crate_type in &self.opts.crate_types {
-            match crate_type {
-                CrateType::Executable
-                | CrateType::Dylib
-                | CrateType::Rlib
-                | CrateType::Staticlib
-                | CrateType::Cdylib => continue,
-                CrateType::ProcMacro => return false,
-            }
-        }
-
         let has_split_debuginfo = match self.split_debuginfo() {
             SplitDebuginfo::Off => false,
             SplitDebuginfo::Packed => true,

From 8364a0626038ab4d22018d5223c9adda4be3aa49 Mon Sep 17 00:00:00 2001
From: Oli Scherer <git-spam-no-reply9815368754983@oli-obk.de>
Date: Mon, 4 Mar 2024 11:25:56 +0000
Subject: [PATCH 18/27] Merge the impl trait in assoc type collector into the
 opaque type collector and use a runtime switch instead

---
 compiler/rustc_ty_utils/src/opaque_types.rs   | 99 ++++---------------
 .../hidden_behind_struct_field3.rs            |  2 +-
 .../hidden_behind_struct_field3.stderr        | 15 +++
 3 files changed, 34 insertions(+), 82 deletions(-)
 create mode 100644 tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.stderr

diff --git a/compiler/rustc_ty_utils/src/opaque_types.rs b/compiler/rustc_ty_utils/src/opaque_types.rs
index 86c7551882aab..282595169737d 100644
--- a/compiler/rustc_ty_utils/src/opaque_types.rs
+++ b/compiler/rustc_ty_utils/src/opaque_types.rs
@@ -22,11 +22,20 @@ struct OpaqueTypeCollector<'tcx> {
     seen: FxHashSet<LocalDefId>,
 
     span: Option<Span>,
+
+    mode: CollectionMode,
+}
+
+enum CollectionMode {
+    /// For impl trait in assoc types we only permit collecting them from
+    /// associated types of the same impl block.
+    ImplTraitInAssocTypes,
+    TypeAliasImplTraitTransition,
 }
 
 impl<'tcx> OpaqueTypeCollector<'tcx> {
-    fn new(tcx: TyCtxt<'tcx>, item: LocalDefId) -> Self {
-        Self { tcx, opaques: Vec::new(), item, seen: Default::default(), span: None }
+    fn new(tcx: TyCtxt<'tcx>, item: LocalDefId, mode: CollectionMode) -> Self {
+        Self { tcx, opaques: Vec::new(), item, seen: Default::default(), span: None, mode }
     }
 
     fn span(&self) -> Span {
@@ -251,6 +260,9 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for OpaqueTypeCollector<'tcx> {
                 }
             }
             ty::Adt(def, _) if def.did().is_local() => {
+                if let CollectionMode::ImplTraitInAssocTypes = self.mode {
+                    return ControlFlow::Continue(());
+                }
                 if !self.seen.insert(def.did().expect_local()) {
                     return ControlFlow::Continue(());
                 }
@@ -275,89 +287,13 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for OpaqueTypeCollector<'tcx> {
     }
 }
 
-struct ImplTraitInAssocTypeCollector<'tcx>(OpaqueTypeCollector<'tcx>);
-
-impl<'tcx> super::sig_types::SpannedTypeVisitor<'tcx> for ImplTraitInAssocTypeCollector<'tcx> {
-    #[instrument(skip(self), ret, level = "trace")]
-    fn visit(&mut self, span: Span, value: impl TypeVisitable<TyCtxt<'tcx>>) -> ControlFlow<!> {
-        let old = self.0.span;
-        self.0.span = Some(span);
-        value.visit_with(self);
-        self.0.span = old;
-
-        ControlFlow::Continue(())
-    }
-}
-
-impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ImplTraitInAssocTypeCollector<'tcx> {
-    #[instrument(skip(self), ret, level = "trace")]
-    fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<!> {
-        t.super_visit_with(self)?;
-        match t.kind() {
-            ty::Alias(ty::Opaque, alias_ty) if alias_ty.def_id.is_local() => {
-                self.0.visit_opaque_ty(alias_ty);
-            }
-            ty::Alias(ty::Projection, alias_ty) => {
-                // This avoids having to do normalization of `Self::AssocTy` by only
-                // supporting the case of a method defining opaque types from assoc types
-                // in the same impl block.
-                let parent_trait_ref = self
-                    .0
-                    .parent_trait_ref()
-                    .expect("impl trait in assoc type collector used on non-assoc item");
-                // If the trait ref of the associated item and the impl differs,
-                // then we can't use the impl's identity args below, so
-                // just skip.
-                if alias_ty.trait_ref(self.0.tcx) == parent_trait_ref {
-                    let parent = self.0.parent().expect("we should have a parent here");
-
-                    for &assoc in self.0.tcx.associated_items(parent).in_definition_order() {
-                        trace!(?assoc);
-                        if assoc.trait_item_def_id != Some(alias_ty.def_id) {
-                            continue;
-                        }
-
-                        // If the type is further specializable, then the type_of
-                        // is not actually correct below.
-                        if !assoc.defaultness(self.0.tcx).is_final() {
-                            continue;
-                        }
-
-                        let impl_args = alias_ty.args.rebase_onto(
-                            self.0.tcx,
-                            parent_trait_ref.def_id,
-                            ty::GenericArgs::identity_for_item(self.0.tcx, parent),
-                        );
-
-                        if check_args_compatible(self.0.tcx, assoc, impl_args) {
-                            return self
-                                .0
-                                .tcx
-                                .type_of(assoc.def_id)
-                                .instantiate(self.0.tcx, impl_args)
-                                .visit_with(self);
-                        } else {
-                            self.0.tcx.dcx().span_bug(
-                                self.0.tcx.def_span(assoc.def_id),
-                                "item had incorrect args",
-                            );
-                        }
-                    }
-                }
-            }
-            _ => trace!(kind=?t.kind()),
-        }
-        ControlFlow::Continue(())
-    }
-}
-
 fn impl_trait_in_assoc_types_defined_by<'tcx>(
     tcx: TyCtxt<'tcx>,
     item: LocalDefId,
 ) -> &'tcx ty::List<LocalDefId> {
-    let mut collector = ImplTraitInAssocTypeCollector(OpaqueTypeCollector::new(tcx, item));
+    let mut collector = OpaqueTypeCollector::new(tcx, item, CollectionMode::ImplTraitInAssocTypes);
     super::sig_types::walk_types(tcx, item, &mut collector);
-    tcx.mk_local_def_ids(&collector.0.opaques)
+    tcx.mk_local_def_ids(&collector.opaques)
 }
 
 fn opaque_types_defined_by<'tcx>(
@@ -366,7 +302,8 @@ fn opaque_types_defined_by<'tcx>(
 ) -> &'tcx ty::List<LocalDefId> {
     let kind = tcx.def_kind(item);
     trace!(?kind);
-    let mut collector = OpaqueTypeCollector::new(tcx, item);
+    let mut collector =
+        OpaqueTypeCollector::new(tcx, item, CollectionMode::TypeAliasImplTraitTransition);
     super::sig_types::walk_types(tcx, item, &mut collector);
     match kind {
         DefKind::AssocFn
diff --git a/tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.rs b/tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.rs
index 366767929e4ba..1278563a92c46 100644
--- a/tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.rs
+++ b/tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.rs
@@ -1,7 +1,6 @@
 //! This test demonstrates a bug where we accidentally
 //! detected opaque types in struct fields, but only if nested
 //! in projections of another opaque type.
-//@ check-pass
 
 #![feature(impl_trait_in_assoc_type)]
 
@@ -18,6 +17,7 @@ impl Trait for Bar {
     type Assoc = impl Iterator<Item = Foo>;
     fn foo() -> Self::Assoc {
         vec![Foo { field: () }].into_iter()
+        //~^ ERROR item constrains opaque type that is not in its signature
     }
 }
 
diff --git a/tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.stderr b/tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.stderr
new file mode 100644
index 0000000000000..0570e0303c633
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.stderr
@@ -0,0 +1,15 @@
+error: item constrains opaque type that is not in its signature
+  --> $DIR/hidden_behind_struct_field3.rs:19:27
+   |
+LL |         vec![Foo { field: () }].into_iter()
+   |                           ^^
+   |
+   = note: this item must mention the opaque type in its signature in order to be able to register hidden types
+note: this item must mention the opaque type in its signature in order to be able to register hidden types
+  --> $DIR/hidden_behind_struct_field3.rs:18:8
+   |
+LL |     fn foo() -> Self::Assoc {
+   |        ^^^
+
+error: aborting due to 1 previous error
+

From 4e03c51f7d693258cdffc9d6b66e7930cbe8509f Mon Sep 17 00:00:00 2001
From: David Wood <david@davidtw.co>
Date: Mon, 4 Mar 2024 11:34:10 +0000
Subject: [PATCH 19/27] hir_analysis: enums return `None` in `find_field`

Unnamed union fields with enums are checked for, but if `find_field`
causes an ICE then the compiler won't get to that point.

Signed-off-by: David Wood <david@davidtw.co>
---
 compiler/rustc_hir_analysis/src/collect.rs    |  7 ++-
 .../unnamed-enum-field-issue-121757.rs        | 25 +++++++++++
 .../unnamed-enum-field-issue-121757.stderr    | 45 +++++++++++++++++++
 3 files changed, 76 insertions(+), 1 deletion(-)
 create mode 100644 tests/ui/union/unnamed-fields/unnamed-enum-field-issue-121757.rs
 create mode 100644 tests/ui/union/unnamed-fields/unnamed-enum-field-issue-121757.stderr

diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs
index b6e2695590c13..2cc37651ef521 100644
--- a/compiler/rustc_hir_analysis/src/collect.rs
+++ b/compiler/rustc_hir_analysis/src/collect.rs
@@ -791,7 +791,12 @@ fn convert_enum_variant_types(tcx: TyCtxt<'_>, def_id: DefId) {
 }
 
 fn find_field(tcx: TyCtxt<'_>, (def_id, ident): (DefId, Ident)) -> Option<FieldIdx> {
-    tcx.adt_def(def_id).non_enum_variant().fields.iter_enumerated().find_map(|(idx, field)| {
+    let adt = tcx.adt_def(def_id);
+    if adt.is_enum() {
+        return None;
+    }
+
+    adt.non_enum_variant().fields.iter_enumerated().find_map(|(idx, field)| {
         if field.is_unnamed() {
             let field_ty = tcx.type_of(field.did).instantiate_identity();
             let adt_def = field_ty.ty_adt_def().expect("expect Adt for unnamed field");
diff --git a/tests/ui/union/unnamed-fields/unnamed-enum-field-issue-121757.rs b/tests/ui/union/unnamed-fields/unnamed-enum-field-issue-121757.rs
new file mode 100644
index 0000000000000..5d15ec4cffdb9
--- /dev/null
+++ b/tests/ui/union/unnamed-fields/unnamed-enum-field-issue-121757.rs
@@ -0,0 +1,25 @@
+type NodeId = u32;
+struct Type<'a>(std::marker::PhantomData::<&'a ()>);
+
+type Ast<'ast> = &'ast AstStructure<'ast>;
+
+struct AstStructure<'ast> {
+//~^ ERROR struct with unnamed fields must have `#[repr(C)]` representation
+    id: NodeId,
+    _: AstKind<'ast>
+//~^ ERROR unnamed fields are not yet fully implemented [E0658]
+//~^^ ERROR unnamed fields can only have struct or union types
+}
+
+enum AstKind<'ast> {
+    ExprInt,
+    ExprLambda(Ast<'ast>),
+}
+
+fn compute_types<'tcx,'ast>(ast: Ast<'ast>) -> Type<'tcx>
+{
+    match ast.kind {}
+//~^ ERROR no field `kind` on type `&'ast AstStructure<'ast>` [E0609]
+}
+
+fn main() {}
diff --git a/tests/ui/union/unnamed-fields/unnamed-enum-field-issue-121757.stderr b/tests/ui/union/unnamed-fields/unnamed-enum-field-issue-121757.stderr
new file mode 100644
index 0000000000000..4ea910202de98
--- /dev/null
+++ b/tests/ui/union/unnamed-fields/unnamed-enum-field-issue-121757.stderr
@@ -0,0 +1,45 @@
+error[E0658]: unnamed fields are not yet fully implemented
+  --> $DIR/unnamed-enum-field-issue-121757.rs:9:5
+   |
+LL |     _: AstKind<'ast>
+   |     ^
+   |
+   = note: see issue #49804 <https://github.com/rust-lang/rust/issues/49804> for more information
+   = help: add `#![feature(unnamed_fields)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: struct with unnamed fields must have `#[repr(C)]` representation
+  --> $DIR/unnamed-enum-field-issue-121757.rs:6:1
+   |
+LL | struct AstStructure<'ast> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^ struct `AstStructure` defined here
+   |
+note: unnamed field defined here
+  --> $DIR/unnamed-enum-field-issue-121757.rs:9:5
+   |
+LL |     _: AstKind<'ast>
+   |     ^^^^^^^^^^^^^^^^
+help: add `#[repr(C)]` to this struct
+   |
+LL + #[repr(C)]
+LL | struct AstStructure<'ast> {
+   |
+
+error: unnamed fields can only have struct or union types
+  --> $DIR/unnamed-enum-field-issue-121757.rs:9:5
+   |
+LL |     _: AstKind<'ast>
+   |     ^^^^^^^^^^^^^^^^
+
+error[E0609]: no field `kind` on type `&'ast AstStructure<'ast>`
+  --> $DIR/unnamed-enum-field-issue-121757.rs:21:15
+   |
+LL |     match ast.kind {}
+   |               ^^^^ unknown field
+   |
+   = note: available fields are: `id`, `_`
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0609, E0658.
+For more information about an error, try `rustc --explain E0609`.

From 640e99ccc982586352b1ad94c350af3cbeff3c2e Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume.gomez@huawei.com>
Date: Mon, 4 Mar 2024 14:30:46 +0100
Subject: [PATCH 20/27] Fix duplicated path in the "not found dylib" error

---
 compiler/rustc_metadata/src/creader.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_metadata/src/creader.rs b/compiler/rustc_metadata/src/creader.rs
index f65fe1a29c7cc..564c35f881d60 100644
--- a/compiler/rustc_metadata/src/creader.rs
+++ b/compiler/rustc_metadata/src/creader.rs
@@ -1132,7 +1132,13 @@ fn load_dylib(path: &Path, max_attempts: usize) -> Result<libloading::Library, S
             Err(err) => {
                 // Only try to recover from this specific error.
                 if !matches!(err, libloading::Error::LoadLibraryExW { .. }) {
-                    return Err(err.to_string());
+                    let err = format_dlopen_err(&err);
+                    // We include the path of the dylib in the error ourselves, so
+                    // if it's in the error, we strip it.
+                    if let Some(err) = err.strip_prefix(&format!(": {}", path.display())) {
+                        return Err(err.to_string());
+                    }
+                    return Err(err);
                 }
 
                 last_error = Some(err);

From 5e6e140b0cf44079cd0f42ba8bfcbf874859dd68 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume.gomez@huawei.com>
Date: Mon, 4 Mar 2024 14:31:23 +0100
Subject: [PATCH 21/27] Add regression ui test for duplicated path in dylib
 error

---
 tests/ui/codegen/duplicated-path-in-error.rs     | 7 +++++++
 tests/ui/codegen/duplicated-path-in-error.stderr | 2 ++
 2 files changed, 9 insertions(+)
 create mode 100644 tests/ui/codegen/duplicated-path-in-error.rs
 create mode 100644 tests/ui/codegen/duplicated-path-in-error.stderr

diff --git a/tests/ui/codegen/duplicated-path-in-error.rs b/tests/ui/codegen/duplicated-path-in-error.rs
new file mode 100644
index 0000000000000..cff20dd9bd639
--- /dev/null
+++ b/tests/ui/codegen/duplicated-path-in-error.rs
@@ -0,0 +1,7 @@
+//@ only-linux
+//@ compile-flags: -Zcodegen-backend=/non-existing-one.so
+
+// This test ensures that the error of the "not found dylib" doesn't duplicate
+// the path of the dylib.
+
+fn main() {}
diff --git a/tests/ui/codegen/duplicated-path-in-error.stderr b/tests/ui/codegen/duplicated-path-in-error.stderr
new file mode 100644
index 0000000000000..d0d34e2f93468
--- /dev/null
+++ b/tests/ui/codegen/duplicated-path-in-error.stderr
@@ -0,0 +1,2 @@
+error: couldn't load codegen backend /non-existing-one.so: cannot open shared object file: No such file or directory
+

From 2af01a2fef8909e65171fed6e45e5d568f736773 Mon Sep 17 00:00:00 2001
From: Nadrieril <nadrieril+git@gmail.com>
Date: Mon, 4 Mar 2024 19:35:33 +0100
Subject: [PATCH 22/27] Abort on arity mismatch

As this can cause panics on array accesses later.
---
 .../rustc_pattern_analysis/src/usefulness.rs  | 22 +++++++++++++------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/compiler/rustc_pattern_analysis/src/usefulness.rs b/compiler/rustc_pattern_analysis/src/usefulness.rs
index 0261768d91616..c518844cc5e52 100644
--- a/compiler/rustc_pattern_analysis/src/usefulness.rs
+++ b/compiler/rustc_pattern_analysis/src/usefulness.rs
@@ -1001,19 +1001,26 @@ impl<'p, Cx: TypeCx> PatStack<'p, Cx> {
     /// Only call if `ctor.is_covered_by(self.head().ctor())` is true.
     fn pop_head_constructor(
         &self,
+        cx: &Cx,
         ctor: &Constructor<Cx>,
         ctor_arity: usize,
         ctor_is_relevant: bool,
-    ) -> PatStack<'p, Cx> {
+    ) -> Result<PatStack<'p, Cx>, Cx::Error> {
         // We pop the head pattern and push the new fields extracted from the arguments of
         // `self.head()`.
         let mut new_pats = self.head().specialize(ctor, ctor_arity);
+        if new_pats.len() != ctor_arity {
+            return Err(cx.bug(format_args!(
+                "uncaught type error: pattern {:?} has inconsistent arity (expected arity {ctor_arity})",
+                self.head().as_pat().unwrap()
+            )));
+        }
         new_pats.extend_from_slice(&self.pats[1..]);
         // `ctor` is relevant for this row if it is the actual constructor of this row, or if the
         // row has a wildcard and `ctor` is relevant for wildcards.
         let ctor_is_relevant =
             !matches!(self.head().ctor(), Constructor::Wildcard) || ctor_is_relevant;
-        PatStack { pats: new_pats, relevant: self.relevant && ctor_is_relevant }
+        Ok(PatStack { pats: new_pats, relevant: self.relevant && ctor_is_relevant })
     }
 }
 
@@ -1083,18 +1090,19 @@ impl<'p, Cx: TypeCx> MatrixRow<'p, Cx> {
     /// Only call if `ctor.is_covered_by(self.head().ctor())` is true.
     fn pop_head_constructor(
         &self,
+        cx: &Cx,
         ctor: &Constructor<Cx>,
         ctor_arity: usize,
         ctor_is_relevant: bool,
         parent_row: usize,
-    ) -> MatrixRow<'p, Cx> {
-        MatrixRow {
-            pats: self.pats.pop_head_constructor(ctor, ctor_arity, ctor_is_relevant),
+    ) -> Result<MatrixRow<'p, Cx>, Cx::Error> {
+        Ok(MatrixRow {
+            pats: self.pats.pop_head_constructor(cx, ctor, ctor_arity, ctor_is_relevant)?,
             parent_row,
             is_under_guard: self.is_under_guard,
             useful: false,
             intersects: BitSet::new_empty(0), // Initialized in `Matrix::expand_and_push`.
-        }
+        })
     }
 }
 
@@ -1217,7 +1225,7 @@ impl<'p, Cx: TypeCx> Matrix<'p, Cx> {
         };
         for (i, row) in self.rows().enumerate() {
             if ctor.is_covered_by(pcx.cx, row.head().ctor())? {
-                let new_row = row.pop_head_constructor(ctor, arity, ctor_is_relevant, i);
+                let new_row = row.pop_head_constructor(pcx.cx, ctor, arity, ctor_is_relevant, i)?;
                 matrix.expand_and_push(new_row);
             }
         }

From fb9161028b8a7f276d552296811630c157471766 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20K=C3=A5re=20Alsaker?= <john.kare.alsaker@gmail.com>
Date: Mon, 4 Mar 2024 20:43:58 +0100
Subject: [PATCH 23/27] Avoid using unnecessary queries when printing the query
 stack in panics

---
 compiler/rustc_query_impl/src/plumbing.rs | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/compiler/rustc_query_impl/src/plumbing.rs b/compiler/rustc_query_impl/src/plumbing.rs
index 1b546bf9103d8..b06d75be3902d 100644
--- a/compiler/rustc_query_impl/src/plumbing.rs
+++ b/compiler/rustc_query_impl/src/plumbing.rs
@@ -17,6 +17,7 @@ use rustc_middle::dep_graph::{
 use rustc_middle::query::on_disk_cache::AbsoluteBytePos;
 use rustc_middle::query::on_disk_cache::{CacheDecoder, CacheEncoder, EncodedDepNodeIndex};
 use rustc_middle::query::Key;
+use rustc_middle::ty::print::with_reduced_queries;
 use rustc_middle::ty::tls::{self, ImplicitCtxt};
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_query_system::dep_graph::{DepNodeParams, HasDepContext};
@@ -304,6 +305,10 @@ pub(crate) fn create_query_frame<
     kind: DepKind,
     name: &'static str,
 ) -> QueryStackFrame {
+    // If reduced queries are requested, we may be printing a query stack due
+    // to a panic. Avoid using `default_span` and `def_kind` in that case.
+    let reduce_queries = with_reduced_queries();
+
     // Avoid calling queries while formatting the description
     let description = ty::print::with_no_queries!(do_describe(tcx, key));
     let description = if tcx.sess.verbose_internals() {
@@ -311,7 +316,7 @@ pub(crate) fn create_query_frame<
     } else {
         description
     };
-    let span = if kind == dep_graph::dep_kinds::def_span {
+    let span = if kind == dep_graph::dep_kinds::def_span || reduce_queries {
         // The `def_span` query is used to calculate `default_span`,
         // so exit to avoid infinite recursion.
         None
@@ -319,7 +324,7 @@ pub(crate) fn create_query_frame<
         Some(key.default_span(tcx))
     };
     let def_id = key.key_as_def_id();
-    let def_kind = if kind == dep_graph::dep_kinds::def_kind {
+    let def_kind = if kind == dep_graph::dep_kinds::def_kind || reduce_queries {
         // Try to avoid infinite recursion.
         None
     } else {

From 86e88fccd34ec30b95627a5b7d3707a2cc163d87 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Mon, 4 Mar 2024 22:05:32 +0100
Subject: [PATCH 24/27] interpret/cast: make more matches on FloatTy properly
 exhaustive

---
 .../rustc_const_eval/src/interpret/cast.rs    | 58 +++++++++++--------
 1 file changed, 35 insertions(+), 23 deletions(-)

diff --git a/compiler/rustc_const_eval/src/interpret/cast.rs b/compiler/rustc_const_eval/src/interpret/cast.rs
index a88e130cd4b78..d291f9e59185f 100644
--- a/compiler/rustc_const_eval/src/interpret/cast.rs
+++ b/compiler/rustc_const_eval/src/interpret/cast.rs
@@ -182,13 +182,14 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     ) -> InterpResult<'tcx, ImmTy<'tcx, M::Provenance>> {
         use rustc_type_ir::TyKind::*;
 
-        let val = match src.layout.ty.kind() {
-            // Floating point
-            Float(FloatTy::F32) => self.cast_from_float(src.to_scalar().to_f32()?, cast_to.ty),
-            Float(FloatTy::F64) => self.cast_from_float(src.to_scalar().to_f64()?, cast_to.ty),
-            _ => {
-                bug!("Can't cast 'Float' type into {}", cast_to.ty);
-            }
+        let Float(fty) = src.layout.ty.kind() else {
+            bug!("FloatToFloat/FloatToInt cast: source type {} is not a float type", src.layout.ty)
+        };
+        let val = match fty {
+            FloatTy::F16 => unimplemented!("f16_f128"),
+            FloatTy::F32 => self.cast_from_float(src.to_scalar().to_f32()?, cast_to.ty),
+            FloatTy::F64 => self.cast_from_float(src.to_scalar().to_f64()?, cast_to.ty),
+            FloatTy::F128 => unimplemented!("f16_f128"),
         };
         Ok(ImmTy::from_scalar(val, cast_to))
     }
@@ -275,6 +276,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         trace!("cast_from_scalar: {}, {} -> {}", v, src_layout.ty, cast_ty);
 
         Ok(match *cast_ty.kind() {
+            // int -> int
             Int(_) | Uint(_) => {
                 let size = match *cast_ty.kind() {
                     Int(t) => Integer::from_int_ty(self, t).size(),
@@ -285,15 +287,26 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 Scalar::from_uint(v, size)
             }
 
-            Float(FloatTy::F32) if signed => Scalar::from_f32(Single::from_i128(v as i128).value),
-            Float(FloatTy::F64) if signed => Scalar::from_f64(Double::from_i128(v as i128).value),
-            Float(FloatTy::F32) => Scalar::from_f32(Single::from_u128(v).value),
-            Float(FloatTy::F64) => Scalar::from_f64(Double::from_u128(v).value),
-
-            Char => {
-                // `u8` to `char` cast
-                Scalar::from_u32(u8::try_from(v).unwrap().into())
+            // signed int -> float
+            Float(fty) if signed => {
+                let v = v as i128;
+                match fty {
+                    FloatTy::F16 => unimplemented!("f16_f128"),
+                    FloatTy::F32 => Scalar::from_f32(Single::from_i128(v).value),
+                    FloatTy::F64 => Scalar::from_f64(Double::from_i128(v).value),
+                    FloatTy::F128 => unimplemented!("f16_f128"),
+                }
             }
+            // unsiged int -> float
+            Float(fty) => match fty {
+                FloatTy::F16 => unimplemented!("f16_f128"),
+                FloatTy::F32 => Scalar::from_f32(Single::from_u128(v).value),
+                FloatTy::F64 => Scalar::from_f64(Double::from_u128(v).value),
+                FloatTy::F128 => unimplemented!("f16_f128"),
+            },
+
+            // u8 -> char
+            Char => Scalar::from_u32(u8::try_from(v).unwrap().into()),
 
             // Casts to bool are not permitted by rustc, no need to handle them here.
             _ => span_bug!(self.cur_span(), "invalid int to {} cast", cast_ty),
@@ -339,14 +352,13 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 let v = f.to_i128(size.bits_usize()).value;
                 Scalar::from_int(v, size)
             }
-            // float -> f32
-            Float(FloatTy::F32) => {
-                Scalar::from_f32(adjust_nan(self, f, f.convert(&mut false).value))
-            }
-            // float -> f64
-            Float(FloatTy::F64) => {
-                Scalar::from_f64(adjust_nan(self, f, f.convert(&mut false).value))
-            }
+            // float -> float
+            Float(fty) => match fty {
+                FloatTy::F16 => unimplemented!("f16_f128"),
+                FloatTy::F32 => Scalar::from_f32(adjust_nan(self, f, f.convert(&mut false).value)),
+                FloatTy::F64 => Scalar::from_f64(adjust_nan(self, f, f.convert(&mut false).value)),
+                FloatTy::F128 => unimplemented!("f16_f128"),
+            },
             // That's it.
             _ => span_bug!(self.cur_span(), "invalid float to {} cast", dest_ty),
         }

From 681dc3828344ab79d34f356a9c08e685ed5ac236 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Mon, 4 Mar 2024 23:18:02 +0100
Subject: [PATCH 25/27] typo
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Rémy Rakic <remy.rakic+github@gmail.com>
---
 compiler/rustc_const_eval/src/interpret/cast.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/rustc_const_eval/src/interpret/cast.rs b/compiler/rustc_const_eval/src/interpret/cast.rs
index d291f9e59185f..2cebea9d145bb 100644
--- a/compiler/rustc_const_eval/src/interpret/cast.rs
+++ b/compiler/rustc_const_eval/src/interpret/cast.rs
@@ -297,7 +297,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                     FloatTy::F128 => unimplemented!("f16_f128"),
                 }
             }
-            // unsiged int -> float
+            // unsigned int -> float
             Float(fty) => match fty {
                 FloatTy::F16 => unimplemented!("f16_f128"),
                 FloatTy::F32 => Scalar::from_f32(Single::from_u128(v).value),

From 4dbd2562b4e2c464218a2949442becad34d55955 Mon Sep 17 00:00:00 2001
From: Christopher Durham <cad97@cad97.com>
Date: Tue, 13 Feb 2024 22:24:29 -0500
Subject: [PATCH 26/27] Explain use of display adapters

---
 library/core/src/fmt/mod.rs | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/library/core/src/fmt/mod.rs b/library/core/src/fmt/mod.rs
index e1b7b46a1ed2f..f82e8a0d60bff 100644
--- a/library/core/src/fmt/mod.rs
+++ b/library/core/src/fmt/mod.rs
@@ -633,6 +633,23 @@ pub use macros::Debug;
 /// [tostring]: ../../std/string/trait.ToString.html
 /// [tostring_function]: ../../std/string/trait.ToString.html#tymethod.to_string
 ///
+/// # Internationalization
+///
+/// Because a type only has one `Display` implementation, it is often preferable
+/// to only implement `Display` when there is a single most "obvious" way that
+/// values can be formatted as text. This could mean formatting according to the
+/// "invariant" culture and "undefined" locale, or it could mean that the type
+/// display is designed for a specific culture/locale, such as developer logs.
+///
+/// If not all values have a justifiably canonical textual format or if you want
+/// to support alternative formats not covered by the standard set of possible
+/// [formatting traits], the most flexible approach is display adapters: methods
+/// like [`str::escape_default`] or [`Path::display`] which create a wrapper
+/// implementing `Display` to output the specific display format.
+///
+/// [formatting traits]: ../../std/fmt/index.html#formatting-traits
+/// [`Path::display`]: ../../std/path/struct.Path.html#method.display
+///
 /// # Examples
 ///
 /// Implementing `Display` on a type:

From 215a4b6c2d71f2f7dd6254fcecbfc15bbc6fb392 Mon Sep 17 00:00:00 2001
From: Christopher Durham <cad97@cad97.com>
Date: Mon, 4 Mar 2024 19:49:45 -0500
Subject: [PATCH 27/27] doc wording improvements

Co-authored-by: Simon Farnsworth <simon@farnz.org.uk>
---
 library/core/src/fmt/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/core/src/fmt/mod.rs b/library/core/src/fmt/mod.rs
index f82e8a0d60bff..4d73c8c3f99a9 100644
--- a/library/core/src/fmt/mod.rs
+++ b/library/core/src/fmt/mod.rs
@@ -635,7 +635,7 @@ pub use macros::Debug;
 ///
 /// # Internationalization
 ///
-/// Because a type only has one `Display` implementation, it is often preferable
+/// Because a type can only have one `Display` implementation, it is often preferable
 /// to only implement `Display` when there is a single most "obvious" way that
 /// values can be formatted as text. This could mean formatting according to the
 /// "invariant" culture and "undefined" locale, or it could mean that the type