From 4c4e43035f8b8bcc171e4a359bb5b42108eadf41 Mon Sep 17 00:00:00 2001
From: Dan Gohman <dev@sunfishcode.online>
Date: Fri, 4 Feb 2022 13:33:06 -0800
Subject: [PATCH 01/16] Rename `BorrowedFd::borrow_raw_fd` to
 `BorrowedFd::borrow_raw`.

Also, rename `BorrowedHandle::borrow_raw_handle` and
`BorrowedSocket::borrow_raw_socket` to `BorrowedHandle::borrow_raw` and
`BorrowedSocket::borrow_raw`.

This is just a minor rename to reduce redundancy in the user code calling
these functions, and to eliminate an inessential difference between
`BorrowedFd` code and `BorrowedHandle`/`BorrowedSocket` code.

While here, add a simple test exercising `BorrowedFd::borrow_raw_fd`.
---
 library/std/src/os/fd/mod.rs            |  3 +++
 library/std/src/os/fd/owned.rs          |  4 +--
 library/std/src/os/fd/tests.rs          | 34 +++++++++++++++++++++++++
 library/std/src/os/windows/io/handle.rs | 24 ++++++++---------
 library/std/src/os/windows/io/socket.rs | 10 ++++----
 library/std/src/sys/unix/stdio.rs       | 12 ++++-----
 6 files changed, 62 insertions(+), 25 deletions(-)
 create mode 100644 library/std/src/os/fd/tests.rs

diff --git a/library/std/src/os/fd/mod.rs b/library/std/src/os/fd/mod.rs
index df11dc21aa7a6..13bb079194fbe 100644
--- a/library/std/src/os/fd/mod.rs
+++ b/library/std/src/os/fd/mod.rs
@@ -11,3 +11,6 @@ pub mod owned;
 
 // Implementations for `AsRawFd` etc. for network types.
 mod net;
+
+#[cfg(test)]
+mod tests;
diff --git a/library/std/src/os/fd/owned.rs b/library/std/src/os/fd/owned.rs
index 0b6588db92c83..1b3739d33f395 100644
--- a/library/std/src/os/fd/owned.rs
+++ b/library/std/src/os/fd/owned.rs
@@ -62,7 +62,7 @@ impl BorrowedFd<'_> {
     /// the returned `BorrowedFd`, and it must not have the value `-1`.
     #[inline]
     #[unstable(feature = "io_safety", issue = "87074")]
-    pub unsafe fn borrow_raw_fd(fd: RawFd) -> Self {
+    pub unsafe fn borrow_raw(fd: RawFd) -> Self {
         assert_ne!(fd, u32::MAX as RawFd);
         // SAFETY: we just asserted that the value is in the valid range and isn't `-1` (the only value bigger than `0xFF_FF_FF_FE` unsigned)
         unsafe { Self { fd, _phantom: PhantomData } }
@@ -215,7 +215,7 @@ impl AsFd for OwnedFd {
         // Safety: `OwnedFd` and `BorrowedFd` have the same validity
         // invariants, and the `BorrowdFd` is bounded by the lifetime
         // of `&self`.
-        unsafe { BorrowedFd::borrow_raw_fd(self.as_raw_fd()) }
+        unsafe { BorrowedFd::borrow_raw(self.as_raw_fd()) }
     }
 }
 
diff --git a/library/std/src/os/fd/tests.rs b/library/std/src/os/fd/tests.rs
new file mode 100644
index 0000000000000..be920a2b38c65
--- /dev/null
+++ b/library/std/src/os/fd/tests.rs
@@ -0,0 +1,34 @@
+#[cfg(any(unix, target_os = "wasi"))]
+#[test]
+fn test_raw_fd() {
+    #[cfg(unix)]
+    use crate::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd, BorrowedFd};
+    #[cfg(target_os = "wasi")]
+    use crate::os::wasi::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd, BorrowedFd};
+
+    let raw_fd: RawFd = crate::io::stdin().as_raw_fd();
+
+    let stdin_as_file = unsafe { crate::fs::File::from_raw_fd(raw_fd) };
+    assert_eq!(stdin_as_file.as_raw_fd(), raw_fd);
+    assert_eq!(unsafe { BorrowedFd::borrow_raw(raw_fd).as_raw_fd() }, raw_fd);
+    assert_eq!(stdin_as_file.into_raw_fd(), 0);
+}
+
+#[cfg(any(unix, target_os = "wasi"))]
+#[test]
+fn test_fd() {
+    #[cfg(unix)]
+    use crate::os::unix::io::{AsFd, BorrowedFd, OwnedFd, FromRawFd, IntoRawFd, RawFd, AsRawFd};
+    #[cfg(target_os = "wasi")]
+    use crate::os::wasi::io::{AsFd, BorrowedFd, OwnedFd, FromRawFd, IntoRawFd, RawFd, AsRawFd};
+
+    let stdin = crate::io::stdin();
+    let fd: BorrowedFd<'_> = stdin.as_fd();
+    let raw_fd: RawFd = fd.as_raw_fd();
+    let owned_fd: OwnedFd = unsafe { OwnedFd::from_raw_fd(raw_fd) };
+
+    let stdin_as_file = crate::fs::File::from(owned_fd);
+
+    assert_eq!(stdin_as_file.as_fd().as_raw_fd(), raw_fd);
+    assert_eq!(Into::<OwnedFd>::into(stdin_as_file).into_raw_fd(), raw_fd);
+}
diff --git a/library/std/src/os/windows/io/handle.rs b/library/std/src/os/windows/io/handle.rs
index e37ce633a129a..5c224f118b6ea 100644
--- a/library/std/src/os/windows/io/handle.rs
+++ b/library/std/src/os/windows/io/handle.rs
@@ -131,7 +131,7 @@ impl BorrowedHandle<'_> {
     /// [here]: https://devblogs.microsoft.com/oldnewthing/20040302-00/?p=40443
     #[inline]
     #[unstable(feature = "io_safety", issue = "87074")]
-    pub unsafe fn borrow_raw_handle(handle: RawHandle) -> Self {
+    pub unsafe fn borrow_raw(handle: RawHandle) -> Self {
         Self { handle, _phantom: PhantomData }
     }
 }
@@ -329,7 +329,7 @@ impl AsHandle for OwnedHandle {
         // Safety: `OwnedHandle` and `BorrowedHandle` have the same validity
         // invariants, and the `BorrowdHandle` is bounded by the lifetime
         // of `&self`.
-        unsafe { BorrowedHandle::borrow_raw_handle(self.as_raw_handle()) }
+        unsafe { BorrowedHandle::borrow_raw(self.as_raw_handle()) }
     }
 }
 
@@ -357,49 +357,49 @@ impl From<OwnedHandle> for fs::File {
 impl AsHandle for crate::io::Stdin {
     #[inline]
     fn as_handle(&self) -> BorrowedHandle<'_> {
-        unsafe { BorrowedHandle::borrow_raw_handle(self.as_raw_handle()) }
+        unsafe { BorrowedHandle::borrow_raw(self.as_raw_handle()) }
     }
 }
 
 impl<'a> AsHandle for crate::io::StdinLock<'a> {
     #[inline]
     fn as_handle(&self) -> BorrowedHandle<'_> {
-        unsafe { BorrowedHandle::borrow_raw_handle(self.as_raw_handle()) }
+        unsafe { BorrowedHandle::borrow_raw(self.as_raw_handle()) }
     }
 }
 
 impl AsHandle for crate::io::Stdout {
     #[inline]
     fn as_handle(&self) -> BorrowedHandle<'_> {
-        unsafe { BorrowedHandle::borrow_raw_handle(self.as_raw_handle()) }
+        unsafe { BorrowedHandle::borrow_raw(self.as_raw_handle()) }
     }
 }
 
 impl<'a> AsHandle for crate::io::StdoutLock<'a> {
     #[inline]
     fn as_handle(&self) -> BorrowedHandle<'_> {
-        unsafe { BorrowedHandle::borrow_raw_handle(self.as_raw_handle()) }
+        unsafe { BorrowedHandle::borrow_raw(self.as_raw_handle()) }
     }
 }
 
 impl AsHandle for crate::io::Stderr {
     #[inline]
     fn as_handle(&self) -> BorrowedHandle<'_> {
-        unsafe { BorrowedHandle::borrow_raw_handle(self.as_raw_handle()) }
+        unsafe { BorrowedHandle::borrow_raw(self.as_raw_handle()) }
     }
 }
 
 impl<'a> AsHandle for crate::io::StderrLock<'a> {
     #[inline]
     fn as_handle(&self) -> BorrowedHandle<'_> {
-        unsafe { BorrowedHandle::borrow_raw_handle(self.as_raw_handle()) }
+        unsafe { BorrowedHandle::borrow_raw(self.as_raw_handle()) }
     }
 }
 
 impl AsHandle for crate::process::ChildStdin {
     #[inline]
     fn as_handle(&self) -> BorrowedHandle<'_> {
-        unsafe { BorrowedHandle::borrow_raw_handle(self.as_raw_handle()) }
+        unsafe { BorrowedHandle::borrow_raw(self.as_raw_handle()) }
     }
 }
 
@@ -413,7 +413,7 @@ impl From<crate::process::ChildStdin> for OwnedHandle {
 impl AsHandle for crate::process::ChildStdout {
     #[inline]
     fn as_handle(&self) -> BorrowedHandle<'_> {
-        unsafe { BorrowedHandle::borrow_raw_handle(self.as_raw_handle()) }
+        unsafe { BorrowedHandle::borrow_raw(self.as_raw_handle()) }
     }
 }
 
@@ -427,7 +427,7 @@ impl From<crate::process::ChildStdout> for OwnedHandle {
 impl AsHandle for crate::process::ChildStderr {
     #[inline]
     fn as_handle(&self) -> BorrowedHandle<'_> {
-        unsafe { BorrowedHandle::borrow_raw_handle(self.as_raw_handle()) }
+        unsafe { BorrowedHandle::borrow_raw(self.as_raw_handle()) }
     }
 }
 
@@ -441,7 +441,7 @@ impl From<crate::process::ChildStderr> for OwnedHandle {
 impl<T> AsHandle for crate::thread::JoinHandle<T> {
     #[inline]
     fn as_handle(&self) -> BorrowedHandle<'_> {
-        unsafe { BorrowedHandle::borrow_raw_handle(self.as_raw_handle()) }
+        unsafe { BorrowedHandle::borrow_raw(self.as_raw_handle()) }
     }
 }
 
diff --git a/library/std/src/os/windows/io/socket.rs b/library/std/src/os/windows/io/socket.rs
index 26b569bcdd362..6ed44b4b11e61 100644
--- a/library/std/src/os/windows/io/socket.rs
+++ b/library/std/src/os/windows/io/socket.rs
@@ -67,7 +67,7 @@ impl BorrowedSocket<'_> {
     /// `INVALID_SOCKET`.
     #[inline]
     #[unstable(feature = "io_safety", issue = "87074")]
-    pub unsafe fn borrow_raw_socket(socket: RawSocket) -> Self {
+    pub unsafe fn borrow_raw(socket: RawSocket) -> Self {
         debug_assert_ne!(socket, c::INVALID_SOCKET as RawSocket);
         Self { socket, _phantom: PhantomData }
     }
@@ -223,14 +223,14 @@ impl AsSocket for OwnedSocket {
         // Safety: `OwnedSocket` and `BorrowedSocket` have the same validity
         // invariants, and the `BorrowdSocket` is bounded by the lifetime
         // of `&self`.
-        unsafe { BorrowedSocket::borrow_raw_socket(self.as_raw_socket()) }
+        unsafe { BorrowedSocket::borrow_raw(self.as_raw_socket()) }
     }
 }
 
 impl AsSocket for crate::net::TcpStream {
     #[inline]
     fn as_socket(&self) -> BorrowedSocket<'_> {
-        unsafe { BorrowedSocket::borrow_raw_socket(self.as_raw_socket()) }
+        unsafe { BorrowedSocket::borrow_raw(self.as_raw_socket()) }
     }
 }
 
@@ -251,7 +251,7 @@ impl From<OwnedSocket> for crate::net::TcpStream {
 impl AsSocket for crate::net::TcpListener {
     #[inline]
     fn as_socket(&self) -> BorrowedSocket<'_> {
-        unsafe { BorrowedSocket::borrow_raw_socket(self.as_raw_socket()) }
+        unsafe { BorrowedSocket::borrow_raw(self.as_raw_socket()) }
     }
 }
 
@@ -272,7 +272,7 @@ impl From<OwnedSocket> for crate::net::TcpListener {
 impl AsSocket for crate::net::UdpSocket {
     #[inline]
     fn as_socket(&self) -> BorrowedSocket<'_> {
-        unsafe { BorrowedSocket::borrow_raw_socket(self.as_raw_socket()) }
+        unsafe { BorrowedSocket::borrow_raw(self.as_raw_socket()) }
     }
 }
 
diff --git a/library/std/src/sys/unix/stdio.rs b/library/std/src/sys/unix/stdio.rs
index b359987595d30..e4d83ba0ffd13 100644
--- a/library/std/src/sys/unix/stdio.rs
+++ b/library/std/src/sys/unix/stdio.rs
@@ -96,7 +96,7 @@ pub fn panic_output() -> Option<impl io::Write> {
 impl AsFd for io::Stdin {
     #[inline]
     fn as_fd(&self) -> BorrowedFd<'_> {
-        unsafe { BorrowedFd::borrow_raw_fd(libc::STDIN_FILENO) }
+        unsafe { BorrowedFd::borrow_raw(libc::STDIN_FILENO) }
     }
 }
 
@@ -104,7 +104,7 @@ impl AsFd for io::Stdin {
 impl<'a> AsFd for io::StdinLock<'a> {
     #[inline]
     fn as_fd(&self) -> BorrowedFd<'_> {
-        unsafe { BorrowedFd::borrow_raw_fd(libc::STDIN_FILENO) }
+        unsafe { BorrowedFd::borrow_raw(libc::STDIN_FILENO) }
     }
 }
 
@@ -112,7 +112,7 @@ impl<'a> AsFd for io::StdinLock<'a> {
 impl AsFd for io::Stdout {
     #[inline]
     fn as_fd(&self) -> BorrowedFd<'_> {
-        unsafe { BorrowedFd::borrow_raw_fd(libc::STDOUT_FILENO) }
+        unsafe { BorrowedFd::borrow_raw(libc::STDOUT_FILENO) }
     }
 }
 
@@ -120,7 +120,7 @@ impl AsFd for io::Stdout {
 impl<'a> AsFd for io::StdoutLock<'a> {
     #[inline]
     fn as_fd(&self) -> BorrowedFd<'_> {
-        unsafe { BorrowedFd::borrow_raw_fd(libc::STDOUT_FILENO) }
+        unsafe { BorrowedFd::borrow_raw(libc::STDOUT_FILENO) }
     }
 }
 
@@ -128,7 +128,7 @@ impl<'a> AsFd for io::StdoutLock<'a> {
 impl AsFd for io::Stderr {
     #[inline]
     fn as_fd(&self) -> BorrowedFd<'_> {
-        unsafe { BorrowedFd::borrow_raw_fd(libc::STDERR_FILENO) }
+        unsafe { BorrowedFd::borrow_raw(libc::STDERR_FILENO) }
     }
 }
 
@@ -136,6 +136,6 @@ impl AsFd for io::Stderr {
 impl<'a> AsFd for io::StderrLock<'a> {
     #[inline]
     fn as_fd(&self) -> BorrowedFd<'_> {
-        unsafe { BorrowedFd::borrow_raw_fd(libc::STDERR_FILENO) }
+        unsafe { BorrowedFd::borrow_raw(libc::STDERR_FILENO) }
     }
 }

From 7d603dc1b2330713a8739b933ec4fc564ee1127c Mon Sep 17 00:00:00 2001
From: Dan Gohman <dev@sunfishcode.online>
Date: Fri, 4 Feb 2022 13:53:58 -0800
Subject: [PATCH 02/16] x.py fmt

---
 library/std/src/os/fd/tests.rs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/library/std/src/os/fd/tests.rs b/library/std/src/os/fd/tests.rs
index be920a2b38c65..26ef93e3d7110 100644
--- a/library/std/src/os/fd/tests.rs
+++ b/library/std/src/os/fd/tests.rs
@@ -2,9 +2,9 @@
 #[test]
 fn test_raw_fd() {
     #[cfg(unix)]
-    use crate::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd, BorrowedFd};
+    use crate::os::unix::io::{AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, RawFd};
     #[cfg(target_os = "wasi")]
-    use crate::os::wasi::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd, BorrowedFd};
+    use crate::os::wasi::io::{AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, RawFd};
 
     let raw_fd: RawFd = crate::io::stdin().as_raw_fd();
 
@@ -18,9 +18,9 @@ fn test_raw_fd() {
 #[test]
 fn test_fd() {
     #[cfg(unix)]
-    use crate::os::unix::io::{AsFd, BorrowedFd, OwnedFd, FromRawFd, IntoRawFd, RawFd, AsRawFd};
+    use crate::os::unix::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, OwnedFd, RawFd};
     #[cfg(target_os = "wasi")]
-    use crate::os::wasi::io::{AsFd, BorrowedFd, OwnedFd, FromRawFd, IntoRawFd, RawFd, AsRawFd};
+    use crate::os::wasi::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, OwnedFd, RawFd};
 
     let stdin = crate::io::stdin();
     let fd: BorrowedFd<'_> = stdin.as_fd();

From 4c7fb9efb7804e489bcf4fe1d3cdf0f7df3b0eff Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Fri, 25 Feb 2022 19:01:44 +0300
Subject: [PATCH 03/16] Add helper function to suggest multiple constraints

Add `rustc_middle::ty::suggest_constraining_type_params` that suggests
adding multiple constraints.

`suggest_constraining_type_param` now just forwards params to this new
function.
---
 compiler/rustc_middle/src/lib.rs            |   1 +
 compiler/rustc_middle/src/ty/diagnostics.rs | 398 ++++++++++++--------
 2 files changed, 236 insertions(+), 163 deletions(-)

diff --git a/compiler/rustc_middle/src/lib.rs b/compiler/rustc_middle/src/lib.rs
index 7ca564f29e659..f977b0fffebb6 100644
--- a/compiler/rustc_middle/src/lib.rs
+++ b/compiler/rustc_middle/src/lib.rs
@@ -56,6 +56,7 @@
 #![feature(nonzero_ops)]
 #![feature(unwrap_infallible)]
 #![feature(decl_macro)]
+#![feature(drain_filter)]
 #![recursion_limit = "512"]
 #![allow(rustc::potential_query_instability)]
 
diff --git a/compiler/rustc_middle/src/ty/diagnostics.rs b/compiler/rustc_middle/src/ty/diagnostics.rs
index 58cf9fa7a8943..99a3d4c7fe4f7 100644
--- a/compiler/rustc_middle/src/ty/diagnostics.rs
+++ b/compiler/rustc_middle/src/ty/diagnostics.rs
@@ -7,6 +7,7 @@ use crate::ty::{
     ProjectionTy, Term, Ty, TyCtxt, TypeAndMut,
 };
 
+use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::{Applicability, Diagnostic};
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
@@ -157,9 +158,17 @@ pub fn suggest_arbitrary_trait_bound(
     true
 }
 
+#[derive(Debug)]
+enum SuggestChangingConstraintsMessage<'a> {
+    RestrictBoundFurther,
+    RestrictType { ty: &'a str },
+    RestrictTypeFurther { ty: &'a str },
+    RemovingQSized,
+}
+
 fn suggest_removing_unsized_bound(
     generics: &hir::Generics<'_>,
-    err: &mut Diagnostic,
+    suggestions: &mut Vec<(Span, String, SuggestChangingConstraintsMessage<'_>)>,
     param_name: &str,
     param: &hir::GenericParam<'_>,
     def_id: Option<DefId>,
@@ -221,13 +230,12 @@ fn suggest_removing_unsized_bound(
                         //             ^^^^^^^^^
                         (_, pos, _, _) => bounds[pos - 1].span().shrink_to_hi().to(bound.span()),
                     };
-                    err.span_suggestion_verbose(
+
+                    suggestions.push((
                         sp,
-                        "consider removing the `?Sized` bound to make the \
-                            type parameter `Sized`",
                         String::new(),
-                        Applicability::MaybeIncorrect,
-                    );
+                        SuggestChangingConstraintsMessage::RemovingQSized,
+                    ));
                 }
             }
             _ => {}
@@ -249,13 +257,12 @@ fn suggest_removing_unsized_bound(
                     //       ^^^^^^^^^
                     (_, pos) => param.bounds[pos - 1].span().shrink_to_hi().to(bound.span()),
                 };
-                err.span_suggestion_verbose(
+
+                suggestions.push((
                     sp,
-                    "consider removing the `?Sized` bound to make the type parameter \
-                        `Sized`",
                     String::new(),
-                    Applicability::MaybeIncorrect,
-                );
+                    SuggestChangingConstraintsMessage::RemovingQSized,
+                ));
             }
             _ => {}
         }
@@ -271,184 +278,249 @@ pub fn suggest_constraining_type_param(
     constraint: &str,
     def_id: Option<DefId>,
 ) -> bool {
-    let param = generics.params.iter().find(|p| p.name.ident().as_str() == param_name);
+    suggest_constraining_type_params(
+        tcx,
+        generics,
+        err,
+        [(param_name, constraint, def_id)].into_iter(),
+    )
+}
 
-    let Some(param) = param else {
-        return false;
-    };
+/// Suggest restricting a type param with a new bound.
+pub fn suggest_constraining_type_params<'a>(
+    tcx: TyCtxt<'_>,
+    generics: &hir::Generics<'_>,
+    err: &mut Diagnostic,
+    param_names_and_constraints: impl Iterator<Item = (&'a str, &'a str, Option<DefId>)>,
+) -> bool {
+    let mut grouped = FxHashMap::default();
+    param_names_and_constraints.for_each(|(param_name, constraint, def_id)| {
+        grouped.entry(param_name).or_insert(Vec::new()).push((constraint, def_id))
+    });
 
-    const MSG_RESTRICT_BOUND_FURTHER: &str = "consider further restricting this bound";
-    let msg_restrict_type = format!("consider restricting type parameter `{}`", param_name);
-    let msg_restrict_type_further =
-        format!("consider further restricting type parameter `{}`", param_name);
+    let mut applicability = Applicability::MachineApplicable;
+    let mut suggestions = Vec::new();
 
-    if def_id == tcx.lang_items().sized_trait() {
-        // Type parameters are already `Sized` by default.
-        err.span_label(param.span, &format!("this type parameter needs to be `{}`", constraint));
-        suggest_removing_unsized_bound(generics, err, param_name, param, def_id);
-        return true;
-    }
-    let mut suggest_restrict = |span| {
-        err.span_suggestion_verbose(
-            span,
-            MSG_RESTRICT_BOUND_FURTHER,
-            format!(" + {}", constraint),
-            Applicability::MachineApplicable,
-        );
-    };
+    for (param_name, mut constraints) in grouped {
+        let param = generics.params.iter().find(|p| p.name.ident().as_str() == param_name);
+        let Some(param) = param else { return false };
 
-    if param_name.starts_with("impl ") {
-        // If there's an `impl Trait` used in argument position, suggest
-        // restricting it:
-        //
-        //   fn foo(t: impl Foo) { ... }
-        //             --------
-        //             |
-        //             help: consider further restricting this bound with `+ Bar`
-        //
-        // Suggestion for tools in this case is:
-        //
-        //   fn foo(t: impl Foo) { ... }
-        //             --------
-        //             |
-        //             replace with: `impl Foo + Bar`
-
-        suggest_restrict(param.span.shrink_to_hi());
-        return true;
-    }
+        {
+            let mut sized_constraints =
+                constraints.drain_filter(|(_, def_id)| *def_id == tcx.lang_items().sized_trait());
+            if let Some((constraint, def_id)) = sized_constraints.next() {
+                applicability = Applicability::MaybeIncorrect;
 
-    if generics.where_clause.predicates.is_empty()
-        // Given `trait Base<T = String>: Super<T>` where `T: Copy`, suggest restricting in the
-        // `where` clause instead of `trait Base<T: Copy = String>: Super<T>`.
-        && !matches!(param.kind, hir::GenericParamKind::Type { default: Some(_), .. })
-    {
-        if let Some(span) = param.bounds_span_for_suggestions() {
-            // If user has provided some bounds, suggest restricting them:
+                err.span_label(
+                    param.span,
+                    &format!("this type parameter needs to be `{}`", constraint),
+                );
+                suggest_removing_unsized_bound(
+                    generics,
+                    &mut suggestions,
+                    param_name,
+                    param,
+                    def_id,
+                );
+            }
+        }
+
+        if constraints.is_empty() {
+            continue;
+        }
+
+        let constraint = constraints.iter().map(|&(c, _)| c).collect::<Vec<_>>().join(" + ");
+        let mut suggest_restrict = |span| {
+            suggestions.push((
+                span,
+                format!(" + {}", constraint),
+                SuggestChangingConstraintsMessage::RestrictBoundFurther,
+            ))
+        };
+
+        if param_name.starts_with("impl ") {
+            // If there's an `impl Trait` used in argument position, suggest
+            // restricting it:
             //
-            //   fn foo<T: Foo>(t: T) { ... }
-            //             ---
+            //   fn foo(t: impl Foo) { ... }
+            //             --------
             //             |
             //             help: consider further restricting this bound with `+ Bar`
             //
             // Suggestion for tools in this case is:
             //
-            //   fn foo<T: Foo>(t: T) { ... }
-            //          --
-            //          |
-            //          replace with: `T: Bar +`
-            suggest_restrict(span);
-        } else {
-            // If user hasn't provided any bounds, suggest adding a new one:
-            //
-            //   fn foo<T>(t: T) { ... }
-            //          - help: consider restricting this type parameter with `T: Foo`
-            err.span_suggestion_verbose(
-                param.span.shrink_to_hi(),
-                &msg_restrict_type,
-                format!(": {}", constraint),
-                Applicability::MachineApplicable,
-            );
+            //   fn foo(t: impl Foo) { ... }
+            //             --------
+            //             |
+            //             replace with: `impl Foo + Bar`
+
+            suggest_restrict(param.span.shrink_to_hi());
+            continue;
         }
 
-        true
-    } else {
-        // This part is a bit tricky, because using the `where` clause user can
-        // provide zero, one or many bounds for the same type parameter, so we
-        // have following cases to consider:
-        //
-        // 1) When the type parameter has been provided zero bounds
-        //
-        //    Message:
-        //      fn foo<X, Y>(x: X, y: Y) where Y: Foo { ... }
-        //             - help: consider restricting this type parameter with `where X: Bar`
-        //
-        //    Suggestion:
-        //      fn foo<X, Y>(x: X, y: Y) where Y: Foo { ... }
-        //                                           - insert: `, X: Bar`
-        //
-        //
-        // 2) When the type parameter has been provided one bound
-        //
-        //    Message:
-        //      fn foo<T>(t: T) where T: Foo { ... }
-        //                            ^^^^^^
-        //                            |
-        //                            help: consider further restricting this bound with `+ Bar`
-        //
-        //    Suggestion:
-        //      fn foo<T>(t: T) where T: Foo { ... }
-        //                            ^^
-        //                            |
-        //                            replace with: `T: Bar +`
-        //
-        //
-        // 3) When the type parameter has been provided many bounds
-        //
-        //    Message:
-        //      fn foo<T>(t: T) where T: Foo, T: Bar {... }
-        //             - help: consider further restricting this type parameter with `where T: Zar`
-        //
-        //    Suggestion:
-        //      fn foo<T>(t: T) where T: Foo, T: Bar {... }
-        //                                          - insert: `, T: Zar`
-        //
-        // Additionally, there may be no `where` clause whatsoever in the case that this was
-        // reached because the generic parameter has a default:
-        //
-        //    Message:
-        //      trait Foo<T=()> {... }
-        //             - help: consider further restricting this type parameter with `where T: Zar`
-        //
-        //    Suggestion:
-        //      trait Foo<T=()> where T: Zar {... }
-        //                     - insert: `where T: Zar`
-
-        if matches!(param.kind, hir::GenericParamKind::Type { default: Some(_), .. })
-            && generics.where_clause.predicates.len() == 0
+        if generics.where_clause.predicates.is_empty()
+        // Given `trait Base<T = String>: Super<T>` where `T: Copy`, suggest restricting in the
+        // `where` clause instead of `trait Base<T: Copy = String>: Super<T>`.
+        && !matches!(param.kind, hir::GenericParamKind::Type { default: Some(_), .. })
         {
-            // Suggest a bound, but there is no existing `where` clause *and* the type param has a
-            // default (`<T=Foo>`), so we suggest adding `where T: Bar`.
-            err.span_suggestion_verbose(
-                generics.where_clause.tail_span_for_suggestion(),
-                &msg_restrict_type_further,
-                format!(" where {}: {}", param_name, constraint),
-                Applicability::MachineApplicable,
-            );
+            if let Some(span) = param.bounds_span_for_suggestions() {
+                // If user has provided some bounds, suggest restricting them:
+                //
+                //   fn foo<T: Foo>(t: T) { ... }
+                //             ---
+                //             |
+                //             help: consider further restricting this bound with `+ Bar`
+                //
+                // Suggestion for tools in this case is:
+                //
+                //   fn foo<T: Foo>(t: T) { ... }
+                //          --
+                //          |
+                //          replace with: `T: Bar +`
+                suggest_restrict(span);
+            } else {
+                // If user hasn't provided any bounds, suggest adding a new one:
+                //
+                //   fn foo<T>(t: T) { ... }
+                //          - help: consider restricting this type parameter with `T: Foo`
+                suggestions.push((
+                    param.span.shrink_to_hi(),
+                    format!(": {}", constraint),
+                    SuggestChangingConstraintsMessage::RestrictType { ty: param_name },
+                ));
+            }
         } else {
-            let mut param_spans = Vec::new();
+            // This part is a bit tricky, because using the `where` clause user can
+            // provide zero, one or many bounds for the same type parameter, so we
+            // have following cases to consider:
+            //
+            // 1) When the type parameter has been provided zero bounds
+            //
+            //    Message:
+            //      fn foo<X, Y>(x: X, y: Y) where Y: Foo { ... }
+            //             - help: consider restricting this type parameter with `where X: Bar`
+            //
+            //    Suggestion:
+            //      fn foo<X, Y>(x: X, y: Y) where Y: Foo { ... }
+            //                                           - insert: `, X: Bar`
+            //
+            //
+            // 2) When the type parameter has been provided one bound
+            //
+            //    Message:
+            //      fn foo<T>(t: T) where T: Foo { ... }
+            //                            ^^^^^^
+            //                            |
+            //                            help: consider further restricting this bound with `+ Bar`
+            //
+            //    Suggestion:
+            //      fn foo<T>(t: T) where T: Foo { ... }
+            //                            ^^
+            //                            |
+            //                            replace with: `T: Bar +`
+            //
+            //
+            // 3) When the type parameter has been provided many bounds
+            //
+            //    Message:
+            //      fn foo<T>(t: T) where T: Foo, T: Bar {... }
+            //             - help: consider further restricting this type parameter with `where T: Zar`
+            //
+            //    Suggestion:
+            //      fn foo<T>(t: T) where T: Foo, T: Bar {... }
+            //                                          - insert: `, T: Zar`
+            //
+            // Additionally, there may be no `where` clause whatsoever in the case that this was
+            // reached because the generic parameter has a default:
+            //
+            //    Message:
+            //      trait Foo<T=()> {... }
+            //             - help: consider further restricting this type parameter with `where T: Zar`
+            //
+            //    Suggestion:
+            //      trait Foo<T=()> where T: Zar {... }
+            //                     - insert: `where T: Zar`
 
-            for predicate in generics.where_clause.predicates {
-                if let WherePredicate::BoundPredicate(WhereBoundPredicate {
-                    span,
-                    bounded_ty,
-                    ..
-                }) = predicate
-                {
-                    if let TyKind::Path(QPath::Resolved(_, path)) = &bounded_ty.kind {
-                        if let Some(segment) = path.segments.first() {
-                            if segment.ident.to_string() == param_name {
-                                param_spans.push(span);
+            if matches!(param.kind, hir::GenericParamKind::Type { default: Some(_), .. })
+                && generics.where_clause.predicates.len() == 0
+            {
+                // Suggest a bound, but there is no existing `where` clause *and* the type param has a
+                // default (`<T=Foo>`), so we suggest adding `where T: Bar`.
+                suggestions.push((
+                    generics.where_clause.tail_span_for_suggestion(),
+                    format!(" where {}: {}", param_name, constraint),
+                    SuggestChangingConstraintsMessage::RestrictTypeFurther { ty: param_name },
+                ));
+            } else {
+                let mut param_spans = Vec::new();
+
+                for predicate in generics.where_clause.predicates {
+                    if let WherePredicate::BoundPredicate(WhereBoundPredicate {
+                        span,
+                        bounded_ty,
+                        ..
+                    }) = predicate
+                    {
+                        if let TyKind::Path(QPath::Resolved(_, path)) = &bounded_ty.kind {
+                            if let Some(segment) = path.segments.first() {
+                                if segment.ident.to_string() == param_name {
+                                    param_spans.push(span);
+                                }
                             }
                         }
                     }
                 }
-            }
 
-            match param_spans[..] {
-                [&param_span] => suggest_restrict(param_span.shrink_to_hi()),
-                _ => {
-                    err.span_suggestion_verbose(
-                        generics.where_clause.tail_span_for_suggestion(),
-                        &msg_restrict_type_further,
-                        format!(", {}: {}", param_name, constraint),
-                        Applicability::MachineApplicable,
-                    );
+                match param_spans[..] {
+                    [&param_span] => suggest_restrict(param_span.shrink_to_hi()),
+                    _ => {
+                        suggestions.push((
+                            generics.where_clause.tail_span_for_suggestion(),
+                            constraints
+                                .iter()
+                                .map(|&(constraint, _)| format!(", {}: {}", param_name, constraint))
+                                .collect::<String>(),
+                            SuggestChangingConstraintsMessage::RestrictTypeFurther {
+                                ty: param_name,
+                            },
+                        ));
+                    }
                 }
             }
         }
+    }
 
-        true
+    if suggestions.len() == 1 {
+        let (span, suggestion, msg) = suggestions.pop().unwrap();
+
+        let s;
+        let msg = match msg {
+            SuggestChangingConstraintsMessage::RestrictBoundFurther => {
+                "consider further restricting this bound"
+            }
+            SuggestChangingConstraintsMessage::RestrictType { ty } => {
+                s = format!("consider restricting type parameter `{}`", ty);
+                &s
+            }
+            SuggestChangingConstraintsMessage::RestrictTypeFurther { ty } => {
+                s = format!("consider further restricting type parameter `{}`", ty);
+                &s
+            }
+            SuggestChangingConstraintsMessage::RemovingQSized => {
+                "consider removing the `?Sized` bound to make the type parameter `Sized`"
+            }
+        };
+
+        err.span_suggestion_verbose(span, msg, suggestion, applicability);
+    } else {
+        err.multipart_suggestion_verbose(
+            "consider restricting type parameters",
+            suggestions.into_iter().map(|(span, suggestion, _)| (span, suggestion)).collect(),
+            applicability,
+        );
     }
+
+    true
 }
 
 /// Collect al types that have an implicit `'static` obligation that we could suggest `'_` for.

From 765205b9b8274f6437d3fee291bc80e7e61a0af0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lo=C3=AFc=20BRANSTETT?= <lolo.branstett@numericable.fr>
Date: Sun, 27 Feb 2022 22:26:24 +0100
Subject: [PATCH 04/16] Improve allowness of the unexpected_cfgs lint

---
 compiler/rustc_attr/src/builtin.rs            | 14 +++++++----
 compiler/rustc_builtin_macros/src/cfg.rs      |  7 +++++-
 compiler/rustc_builtin_macros/src/cfg_eval.rs |  6 +++--
 compiler/rustc_builtin_macros/src/derive.rs   |  7 +++++-
 compiler/rustc_codegen_ssa/src/back/link.rs   |  3 ++-
 compiler/rustc_expand/src/config.rs           | 20 ++++++++++++----
 compiler/rustc_expand/src/expand.rs           | 23 +++++++++++--------
 compiler/rustc_interface/src/passes.rs        |  3 ++-
 compiler/rustc_metadata/src/native_libs.rs    |  3 ++-
 src/test/ui/check-cfg/allow-macro-cfg.rs      | 14 +++++++++++
 src/test/ui/check-cfg/allow-same-level.rs     | 11 +++++++++
 src/test/ui/check-cfg/allow-same-level.stderr | 10 ++++++++
 src/test/ui/check-cfg/allow-top-level.rs      | 15 ++++++++++++
 src/test/ui/check-cfg/allow-upper-level.rs    | 12 ++++++++++
 14 files changed, 122 insertions(+), 26 deletions(-)
 create mode 100644 src/test/ui/check-cfg/allow-macro-cfg.rs
 create mode 100644 src/test/ui/check-cfg/allow-same-level.rs
 create mode 100644 src/test/ui/check-cfg/allow-same-level.stderr
 create mode 100644 src/test/ui/check-cfg/allow-top-level.rs
 create mode 100644 src/test/ui/check-cfg/allow-upper-level.rs

diff --git a/compiler/rustc_attr/src/builtin.rs b/compiler/rustc_attr/src/builtin.rs
index 68b536da9f70f..846abce9d6a6e 100644
--- a/compiler/rustc_attr/src/builtin.rs
+++ b/compiler/rustc_attr/src/builtin.rs
@@ -1,8 +1,7 @@
 //! Parsing and validation of builtin attributes
 
 use rustc_ast as ast;
-use rustc_ast::node_id::CRATE_NODE_ID;
-use rustc_ast::{Attribute, Lit, LitKind, MetaItem, MetaItemKind, NestedMetaItem};
+use rustc_ast::{Attribute, Lit, LitKind, MetaItem, MetaItemKind, NestedMetaItem, NodeId};
 use rustc_ast_pretty::pprust;
 use rustc_errors::{struct_span_err, Applicability};
 use rustc_feature::{find_gated_cfg, is_builtin_attr_name, Features, GatedCfg};
@@ -436,7 +435,12 @@ pub fn find_crate_name(sess: &Session, attrs: &[Attribute]) -> Option<Symbol> {
 }
 
 /// Tests if a cfg-pattern matches the cfg set
-pub fn cfg_matches(cfg: &ast::MetaItem, sess: &ParseSess, features: Option<&Features>) -> bool {
+pub fn cfg_matches(
+    cfg: &ast::MetaItem,
+    sess: &ParseSess,
+    lint_node_id: NodeId,
+    features: Option<&Features>,
+) -> bool {
     eval_condition(cfg, sess, features, &mut |cfg| {
         try_gate_cfg(cfg, sess, features);
         let error = |span, msg| {
@@ -470,7 +474,7 @@ pub fn cfg_matches(cfg: &ast::MetaItem, sess: &ParseSess, features: Option<&Feat
                         sess.buffer_lint_with_diagnostic(
                             UNEXPECTED_CFGS,
                             cfg.span,
-                            CRATE_NODE_ID,
+                            lint_node_id,
                             "unexpected `cfg` condition name",
                             BuiltinLintDiagnostics::UnexpectedCfg(ident.span, name, None),
                         );
@@ -482,7 +486,7 @@ pub fn cfg_matches(cfg: &ast::MetaItem, sess: &ParseSess, features: Option<&Feat
                             sess.buffer_lint_with_diagnostic(
                                 UNEXPECTED_CFGS,
                                 cfg.span,
-                                CRATE_NODE_ID,
+                                lint_node_id,
                                 "unexpected `cfg` condition value",
                                 BuiltinLintDiagnostics::UnexpectedCfg(
                                     cfg.name_value_literal_span().unwrap(),
diff --git a/compiler/rustc_builtin_macros/src/cfg.rs b/compiler/rustc_builtin_macros/src/cfg.rs
index 1e1cf917c6093..f5ef4765df64f 100644
--- a/compiler/rustc_builtin_macros/src/cfg.rs
+++ b/compiler/rustc_builtin_macros/src/cfg.rs
@@ -19,7 +19,12 @@ pub fn expand_cfg(
 
     match parse_cfg(cx, sp, tts) {
         Ok(cfg) => {
-            let matches_cfg = attr::cfg_matches(&cfg, &cx.sess.parse_sess, cx.ecfg.features);
+            let matches_cfg = attr::cfg_matches(
+                &cfg,
+                &cx.sess.parse_sess,
+                cx.current_expansion.lint_node_id,
+                cx.ecfg.features,
+            );
             MacEager::expr(cx.expr_bool(sp, matches_cfg))
         }
         Err(mut err) => {
diff --git a/compiler/rustc_builtin_macros/src/cfg_eval.rs b/compiler/rustc_builtin_macros/src/cfg_eval.rs
index 31086a2acf8cc..6e7b74d835a90 100644
--- a/compiler/rustc_builtin_macros/src/cfg_eval.rs
+++ b/compiler/rustc_builtin_macros/src/cfg_eval.rs
@@ -5,6 +5,7 @@ use rustc_ast::mut_visit::MutVisitor;
 use rustc_ast::ptr::P;
 use rustc_ast::tokenstream::CanSynthesizeMissingTokens;
 use rustc_ast::visit::Visitor;
+use rustc_ast::NodeId;
 use rustc_ast::{mut_visit, visit};
 use rustc_ast::{AstLike, Attribute};
 use rustc_expand::base::{Annotatable, ExtCtxt};
@@ -26,15 +27,16 @@ crate fn expand(
 ) -> Vec<Annotatable> {
     check_builtin_macro_attribute(ecx, meta_item, sym::cfg_eval);
     warn_on_duplicate_attribute(&ecx, &annotatable, sym::cfg_eval);
-    vec![cfg_eval(ecx.sess, ecx.ecfg.features, annotatable)]
+    vec![cfg_eval(ecx.sess, ecx.ecfg.features, annotatable, ecx.current_expansion.lint_node_id)]
 }
 
 crate fn cfg_eval(
     sess: &Session,
     features: Option<&Features>,
     annotatable: Annotatable,
+    lint_node_id: NodeId,
 ) -> Annotatable {
-    CfgEval { cfg: &mut StripUnconfigured { sess, features, config_tokens: true } }
+    CfgEval { cfg: &mut StripUnconfigured { sess, features, config_tokens: true, lint_node_id } }
         .configure_annotatable(annotatable)
         // Since the item itself has already been configured by the `InvocationCollector`,
         // we know that fold result vector will contain exactly one element.
diff --git a/compiler/rustc_builtin_macros/src/derive.rs b/compiler/rustc_builtin_macros/src/derive.rs
index 47d7b6c259e33..61681ec66a48d 100644
--- a/compiler/rustc_builtin_macros/src/derive.rs
+++ b/compiler/rustc_builtin_macros/src/derive.rs
@@ -64,7 +64,12 @@ impl MultiItemModifier for Expander {
                 match &mut resolutions[..] {
                     [] => {}
                     [(_, first_item, _), others @ ..] => {
-                        *first_item = cfg_eval(sess, features, item.clone());
+                        *first_item = cfg_eval(
+                            sess,
+                            features,
+                            item.clone(),
+                            ecx.current_expansion.lint_node_id,
+                        );
                         for (_, item, _) in others {
                             *item = first_item.clone();
                         }
diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index 587453fd8e8d6..9d4b189486ea2 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -1,4 +1,5 @@
 use rustc_arena::TypedArena;
+use rustc_ast::CRATE_NODE_ID;
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
 use rustc_data_structures::memmap::Mmap;
 use rustc_data_structures::temp_dir::MaybeTempDir;
@@ -2434,7 +2435,7 @@ fn add_upstream_native_libraries(
 
 fn relevant_lib(sess: &Session, lib: &NativeLib) -> bool {
     match lib.cfg {
-        Some(ref cfg) => rustc_attr::cfg_matches(cfg, &sess.parse_sess, None),
+        Some(ref cfg) => rustc_attr::cfg_matches(cfg, &sess.parse_sess, CRATE_NODE_ID, None),
         None => true,
     }
 }
diff --git a/compiler/rustc_expand/src/config.rs b/compiler/rustc_expand/src/config.rs
index c0d7bc359bf44..d43c6fec7d5ad 100644
--- a/compiler/rustc_expand/src/config.rs
+++ b/compiler/rustc_expand/src/config.rs
@@ -5,6 +5,7 @@ use rustc_ast::token::{DelimToken, Token, TokenKind};
 use rustc_ast::tokenstream::{AttrAnnotatedTokenStream, AttrAnnotatedTokenTree};
 use rustc_ast::tokenstream::{DelimSpan, Spacing};
 use rustc_ast::tokenstream::{LazyTokenStream, TokenTree};
+use rustc_ast::NodeId;
 use rustc_ast::{self as ast, AstLike, AttrStyle, Attribute, MetaItem};
 use rustc_attr as attr;
 use rustc_data_structures::fx::FxHashMap;
@@ -29,6 +30,7 @@ pub struct StripUnconfigured<'a> {
     /// This is only used for the input to derive macros,
     /// which needs eager expansion of `cfg` and `cfg_attr`
     pub config_tokens: bool,
+    pub lint_node_id: NodeId,
 }
 
 fn get_features(
@@ -196,8 +198,13 @@ fn get_features(
 }
 
 // `cfg_attr`-process the crate's attributes and compute the crate's features.
-pub fn features(sess: &Session, mut krate: ast::Crate) -> (ast::Crate, Features) {
-    let mut strip_unconfigured = StripUnconfigured { sess, features: None, config_tokens: false };
+pub fn features(
+    sess: &Session,
+    mut krate: ast::Crate,
+    lint_node_id: NodeId,
+) -> (ast::Crate, Features) {
+    let mut strip_unconfigured =
+        StripUnconfigured { sess, features: None, config_tokens: false, lint_node_id };
 
     let unconfigured_attrs = krate.attrs.clone();
     let diag = &sess.parse_sess.span_diagnostic;
@@ -353,7 +360,12 @@ impl<'a> StripUnconfigured<'a> {
             );
         }
 
-        if !attr::cfg_matches(&cfg_predicate, &self.sess.parse_sess, self.features) {
+        if !attr::cfg_matches(
+            &cfg_predicate,
+            &self.sess.parse_sess,
+            self.lint_node_id,
+            self.features,
+        ) {
             return vec![];
         }
 
@@ -445,7 +457,7 @@ impl<'a> StripUnconfigured<'a> {
             }
         };
         parse_cfg(&meta_item, &self.sess).map_or(true, |meta_item| {
-            attr::cfg_matches(&meta_item, &self.sess.parse_sess, self.features)
+            attr::cfg_matches(&meta_item, &self.sess.parse_sess, self.lint_node_id, self.features)
         })
     }
 
diff --git a/compiler/rustc_expand/src/expand.rs b/compiler/rustc_expand/src/expand.rs
index bdc9c064a6f9c..36fb14a403e9b 100644
--- a/compiler/rustc_expand/src/expand.rs
+++ b/compiler/rustc_expand/src/expand.rs
@@ -551,11 +551,6 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                 // attribute is expanded. Therefore, we don't need to configure the tokens
                 // Derive macros *can* see the results of cfg-expansion - they are handled
                 // specially in `fully_expand_fragment`
-                cfg: StripUnconfigured {
-                    sess: &self.cx.sess,
-                    features: self.cx.ecfg.features,
-                    config_tokens: false,
-                },
                 cx: self.cx,
                 invocations: Vec::new(),
                 monotonic: self.monotonic,
@@ -1537,12 +1532,20 @@ impl InvocationCollectorNode for AstLikeWrapper<P<ast::Expr>, OptExprTag> {
 
 struct InvocationCollector<'a, 'b> {
     cx: &'a mut ExtCtxt<'b>,
-    cfg: StripUnconfigured<'a>,
     invocations: Vec<(Invocation, Option<Lrc<SyntaxExtension>>)>,
     monotonic: bool,
 }
 
 impl<'a, 'b> InvocationCollector<'a, 'b> {
+    fn cfg(&self) -> StripUnconfigured<'_> {
+        StripUnconfigured {
+            sess: &self.cx.sess,
+            features: self.cx.ecfg.features,
+            config_tokens: false,
+            lint_node_id: self.cx.current_expansion.lint_node_id,
+        }
+    }
+
     fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
         let expn_id = LocalExpnId::fresh_empty();
         let vis = kind.placeholder_visibility();
@@ -1682,7 +1685,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
         attr: ast::Attribute,
         pos: usize,
     ) -> bool {
-        let res = self.cfg.cfg_true(&attr);
+        let res = self.cfg().cfg_true(&attr);
         if res {
             // FIXME: `cfg(TRUE)` attributes do not currently remove themselves during expansion,
             // and some tools like rustdoc and clippy rely on that. Find a way to remove them
@@ -1695,7 +1698,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
 
     fn expand_cfg_attr(&self, node: &mut impl AstLike, attr: ast::Attribute, pos: usize) {
         node.visit_attrs(|attrs| {
-            attrs.splice(pos..pos, self.cfg.expand_cfg_attr(attr, false));
+            attrs.splice(pos..pos, self.cfg().expand_cfg_attr(attr, false));
         });
     }
 
@@ -1717,7 +1720,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
                         continue;
                     }
                     _ => {
-                        Node::pre_flat_map_node_collect_attr(&self.cfg, &attr);
+                        Node::pre_flat_map_node_collect_attr(&self.cfg(), &attr);
                         self.collect_attr((attr, pos, derives), node.to_annotatable(), Node::KIND)
                             .make_ast::<Node>()
                     }
@@ -1881,7 +1884,7 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
     fn visit_expr(&mut self, node: &mut P<ast::Expr>) {
         // FIXME: Feature gating is performed inconsistently between `Expr` and `OptExpr`.
         if let Some(attr) = node.attrs.first() {
-            self.cfg.maybe_emit_expr_attr_err(attr);
+            self.cfg().maybe_emit_expr_attr_err(attr);
         }
         self.visit_node(node)
     }
diff --git a/compiler/rustc_interface/src/passes.rs b/compiler/rustc_interface/src/passes.rs
index c0552fd200be8..951ae0ce2a4c7 100644
--- a/compiler/rustc_interface/src/passes.rs
+++ b/compiler/rustc_interface/src/passes.rs
@@ -2,6 +2,7 @@ use crate::interface::{Compiler, Result};
 use crate::proc_macro_decls;
 use crate::util;
 
+use ast::CRATE_NODE_ID;
 use rustc_ast::mut_visit::MutVisitor;
 use rustc_ast::{self as ast, visit};
 use rustc_borrowck as mir_borrowck;
@@ -188,7 +189,7 @@ pub fn register_plugins<'a>(
         )
     });
 
-    let (krate, features) = rustc_expand::config::features(sess, krate);
+    let (krate, features) = rustc_expand::config::features(sess, krate, CRATE_NODE_ID);
     // these need to be set "early" so that expansion sees `quote` if enabled.
     sess.init_features(features);
 
diff --git a/compiler/rustc_metadata/src/native_libs.rs b/compiler/rustc_metadata/src/native_libs.rs
index dce1b35c6b889..7cdcb6a4ab302 100644
--- a/compiler/rustc_metadata/src/native_libs.rs
+++ b/compiler/rustc_metadata/src/native_libs.rs
@@ -1,3 +1,4 @@
+use rustc_ast::CRATE_NODE_ID;
 use rustc_attr as attr;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::struct_span_err;
@@ -21,7 +22,7 @@ crate fn collect(tcx: TyCtxt<'_>) -> Vec<NativeLib> {
 
 crate fn relevant_lib(sess: &Session, lib: &NativeLib) -> bool {
     match lib.cfg {
-        Some(ref cfg) => attr::cfg_matches(cfg, &sess.parse_sess, None),
+        Some(ref cfg) => attr::cfg_matches(cfg, &sess.parse_sess, CRATE_NODE_ID, None),
         None => true,
     }
 }
diff --git a/src/test/ui/check-cfg/allow-macro-cfg.rs b/src/test/ui/check-cfg/allow-macro-cfg.rs
new file mode 100644
index 0000000000000..8016a4d190cc3
--- /dev/null
+++ b/src/test/ui/check-cfg/allow-macro-cfg.rs
@@ -0,0 +1,14 @@
+// This test check that local #[allow(unexpected_cfgs)] works
+//
+// check-pass
+// compile-flags:--check-cfg=names() -Z unstable-options
+
+#[allow(unexpected_cfgs)]
+fn foo() {
+    if cfg!(FALSE) {}
+}
+
+fn main() {
+    #[allow(unexpected_cfgs)]
+    if cfg!(FALSE) {}
+}
diff --git a/src/test/ui/check-cfg/allow-same-level.rs b/src/test/ui/check-cfg/allow-same-level.rs
new file mode 100644
index 0000000000000..6c869dc420235
--- /dev/null
+++ b/src/test/ui/check-cfg/allow-same-level.rs
@@ -0,0 +1,11 @@
+// This test check that #[allow(unexpected_cfgs)] doesn't work if put on the same level
+//
+// check-pass
+// compile-flags:--check-cfg=names() -Z unstable-options
+
+#[allow(unexpected_cfgs)]
+#[cfg(FALSE)]
+//~^ WARNING unexpected `cfg` condition name
+fn bar() {}
+
+fn main() {}
diff --git a/src/test/ui/check-cfg/allow-same-level.stderr b/src/test/ui/check-cfg/allow-same-level.stderr
new file mode 100644
index 0000000000000..7797de584b9e1
--- /dev/null
+++ b/src/test/ui/check-cfg/allow-same-level.stderr
@@ -0,0 +1,10 @@
+warning: unexpected `cfg` condition name
+  --> $DIR/allow-same-level.rs:7:7
+   |
+LL | #[cfg(FALSE)]
+   |       ^^^^^
+   |
+   = note: `#[warn(unexpected_cfgs)]` on by default
+
+warning: 1 warning emitted
+
diff --git a/src/test/ui/check-cfg/allow-top-level.rs b/src/test/ui/check-cfg/allow-top-level.rs
new file mode 100644
index 0000000000000..d14b0eae5ccdd
--- /dev/null
+++ b/src/test/ui/check-cfg/allow-top-level.rs
@@ -0,0 +1,15 @@
+// This test check that a top-level #![allow(unexpected_cfgs)] works
+//
+// check-pass
+// compile-flags:--check-cfg=names() -Z unstable-options
+
+#![allow(unexpected_cfgs)]
+
+#[cfg(FALSE)]
+fn bar() {}
+
+fn foo() {
+    if cfg!(FALSE) {}
+}
+
+fn main() {}
diff --git a/src/test/ui/check-cfg/allow-upper-level.rs b/src/test/ui/check-cfg/allow-upper-level.rs
new file mode 100644
index 0000000000000..04340694d9c1e
--- /dev/null
+++ b/src/test/ui/check-cfg/allow-upper-level.rs
@@ -0,0 +1,12 @@
+// This test check that #[allow(unexpected_cfgs)] work if put on an upper level
+//
+// check-pass
+// compile-flags:--check-cfg=names() -Z unstable-options
+
+#[allow(unexpected_cfgs)]
+mod aa {
+    #[cfg(FALSE)]
+    fn bar() {}
+}
+
+fn main() {}

From 400d343796065e57e78d92b4cf74c78bec38452a Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Fri, 25 Feb 2022 23:34:25 +0300
Subject: [PATCH 05/16] Suggest adding `Copy` bound when Adt is moved out

Previously we've only suggested adding `Copy` bounds when the type being
moved/copied is a type parameter (generic). With this commit we also
suggest adding bounds when a type
- Can be copy
- All predicates that need to be satisfied for that are based on type
  params

i.e. we will suggest `T: Copy` for `Option<T>`, but won't suggest
anything for `Option<String>`.

Future work: it would be nice to also suggest adding `.clone()` calls
---
 .../src/diagnostics/conflict_errors.rs        | 63 ++++++++++++++++++-
 1 file changed, 62 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
index eb906d5fde7b4..e8ecb3cb6f3e7 100644
--- a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -5,16 +5,21 @@ use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorReported};
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_hir::{AsyncGeneratorKind, GeneratorKind};
+use rustc_infer::infer::TyCtxtInferExt;
+use rustc_infer::traits::ObligationCause;
 use rustc_middle::mir::{
     self, AggregateKind, BindingForm, BorrowKind, ClearCrossCrate, ConstraintCategory,
     FakeReadCause, LocalDecl, LocalInfo, LocalKind, Location, Operand, Place, PlaceRef,
     ProjectionElem, Rvalue, Statement, StatementKind, Terminator, TerminatorKind, VarBindingForm,
 };
-use rustc_middle::ty::{self, suggest_constraining_type_param, Ty};
+use rustc_middle::ty::{
+    self, suggest_constraining_type_param, suggest_constraining_type_params, PredicateKind, Ty,
+};
 use rustc_mir_dataflow::move_paths::{InitKind, MoveOutIndex, MovePathIndex};
 use rustc_span::symbol::sym;
 use rustc_span::{BytePos, MultiSpan, Span, DUMMY_SP};
 use rustc_trait_selection::infer::InferCtxtExt;
+use rustc_trait_selection::traits::TraitEngineExt as _;
 
 use crate::borrow_set::TwoPhaseActivation;
 use crate::borrowck_errors;
@@ -423,7 +428,63 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                             None,
                         );
                     }
+                } else {
+                    // Try to find predicates on *generic params* that would allow copying `ty`
+
+                    let tcx = self.infcx.tcx;
+                    let generics = tcx.generics_of(self.mir_def_id());
+                    if let Some(hir_generics) = tcx
+                        .typeck_root_def_id(self.mir_def_id().to_def_id())
+                        .as_local()
+                        .and_then(|def_id| tcx.hir().get_generics(def_id))
+                    {
+                        let predicates: Result<Vec<_>, _> = tcx.infer_ctxt().enter(|infcx| {
+                            let mut fulfill_cx =
+                                <dyn rustc_infer::traits::TraitEngine<'_>>::new(infcx.tcx);
+
+                            let copy_did = infcx.tcx.lang_items().copy_trait().unwrap();
+                            let cause = ObligationCause::new(
+                                span,
+                                self.mir_hir_id(),
+                                rustc_infer::traits::ObligationCauseCode::MiscObligation,
+                            );
+                            fulfill_cx.register_bound(&infcx, self.param_env, ty, copy_did, cause);
+                            let errors = fulfill_cx.select_where_possible(&infcx);
+
+                            // Only emit suggestion if all required predicates are on generic
+                            errors
+                                .into_iter()
+                                .map(|err| match err.obligation.predicate.kind().skip_binder() {
+                                    PredicateKind::Trait(predicate) => {
+                                        match predicate.self_ty().kind() {
+                                            ty::Param(param_ty) => Ok((
+                                                generics.type_param(param_ty, tcx),
+                                                predicate
+                                                    .trait_ref
+                                                    .print_only_trait_path()
+                                                    .to_string(),
+                                            )),
+                                            _ => Err(()),
+                                        }
+                                    }
+                                    _ => Err(()),
+                                })
+                                .collect()
+                        });
+
+                        if let Ok(predicates) = predicates {
+                            suggest_constraining_type_params(
+                                tcx,
+                                hir_generics,
+                                &mut err,
+                                predicates.iter().map(|(param, constraint)| {
+                                    (param.name.as_str(), &**constraint, None)
+                                }),
+                            );
+                        }
+                    }
                 }
+
                 let span = if let Some(local) = place.as_local() {
                     let decl = &self.body.local_decls[local];
                     Some(decl.source_info.span)

From 879efa84516da086e7461d65fff6797c8ae1cff9 Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Fri, 25 Feb 2022 23:38:00 +0300
Subject: [PATCH 06/16] Add a test for Adt copy suggestions

---
 .../use_of_moved_value_copy_suggestions.rs    |  65 ++++++++
 ...use_of_moved_value_copy_suggestions.stderr | 151 ++++++++++++++++++
 2 files changed, 216 insertions(+)
 create mode 100644 src/test/ui/moves/use_of_moved_value_copy_suggestions.rs
 create mode 100644 src/test/ui/moves/use_of_moved_value_copy_suggestions.stderr

diff --git a/src/test/ui/moves/use_of_moved_value_copy_suggestions.rs b/src/test/ui/moves/use_of_moved_value_copy_suggestions.rs
new file mode 100644
index 0000000000000..0930927c49d66
--- /dev/null
+++ b/src/test/ui/moves/use_of_moved_value_copy_suggestions.rs
@@ -0,0 +1,65 @@
+fn duplicate_t<T>(t: T) -> (T, T) {
+    (t, t) //~ use of moved value: `t`
+}
+
+fn duplicate_opt<T>(t: Option<T>) -> (Option<T>, Option<T>) {
+    (t, t) //~ use of moved value: `t`
+}
+
+fn duplicate_tup1<T>(t: (T,)) -> ((T,), (T,)) {
+    (t, t) //~ use of moved value: `t`
+}
+
+fn duplicate_tup2<A, B>(t: (A, B)) -> ((A, B), (A, B)) {
+    (t, t) //~ use of moved value: `t`
+}
+
+fn duplicate_custom<T>(t: S<T>) -> (S<T>, S<T>) {
+    (t, t) //~ use of moved value: `t`
+}
+
+struct S<T>(T);
+trait Trait {}
+impl<T: Trait + Clone> Clone for S<T> {
+    fn clone(&self) -> Self {
+        Self(self.0.clone())
+    }
+}
+impl<T: Trait + Copy> Copy for S<T> {}
+
+trait A {}
+trait B {}
+
+// Test where bounds are added with different bound placements
+fn duplicate_custom_1<T>(t: S<T>) -> (S<T>, S<T>) where {
+    (t, t) //~ use of moved value: `t`
+}
+
+fn duplicate_custom_2<T>(t: S<T>) -> (S<T>, S<T>)
+where
+    T: A,
+{
+    (t, t) //~ use of moved value: `t`
+}
+
+fn duplicate_custom_3<T>(t: S<T>) -> (S<T>, S<T>)
+where
+    T: A,
+    T: B,
+{
+    (t, t) //~ use of moved value: `t`
+}
+
+fn duplicate_custom_4<T: A>(t: S<T>) -> (S<T>, S<T>)
+where
+    T: B,
+{
+    (t, t) //~ use of moved value: `t`
+}
+
+// `Rc` is not ever `Copy`, we should not suggest adding `T: Copy` constraint
+fn duplicate_rc<T>(t: std::rc::Rc<T>) -> (std::rc::Rc<T>, std::rc::Rc<T>) {
+    (t, t) //~ use of moved value: `t`
+}
+
+fn main() {}
diff --git a/src/test/ui/moves/use_of_moved_value_copy_suggestions.stderr b/src/test/ui/moves/use_of_moved_value_copy_suggestions.stderr
new file mode 100644
index 0000000000000..c32ac2cd78aa0
--- /dev/null
+++ b/src/test/ui/moves/use_of_moved_value_copy_suggestions.stderr
@@ -0,0 +1,151 @@
+error[E0382]: use of moved value: `t`
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:2:9
+   |
+LL | fn duplicate_t<T>(t: T) -> (T, T) {
+   |                   - move occurs because `t` has type `T`, which does not implement the `Copy` trait
+LL |     (t, t)
+   |      -  ^ value used here after move
+   |      |
+   |      value moved here
+   |
+help: consider restricting type parameter `T`
+   |
+LL | fn duplicate_t<T: Copy>(t: T) -> (T, T) {
+   |                 ++++++
+
+error[E0382]: use of moved value: `t`
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:6:9
+   |
+LL | fn duplicate_opt<T>(t: Option<T>) -> (Option<T>, Option<T>) {
+   |                     - move occurs because `t` has type `Option<T>`, which does not implement the `Copy` trait
+LL |     (t, t)
+   |      -  ^ value used here after move
+   |      |
+   |      value moved here
+   |
+help: consider restricting type parameter `T`
+   |
+LL | fn duplicate_opt<T: Copy>(t: Option<T>) -> (Option<T>, Option<T>) {
+   |                   ++++++
+
+error[E0382]: use of moved value: `t`
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:10:9
+   |
+LL | fn duplicate_tup1<T>(t: (T,)) -> ((T,), (T,)) {
+   |                      - move occurs because `t` has type `(T,)`, which does not implement the `Copy` trait
+LL |     (t, t)
+   |      -  ^ value used here after move
+   |      |
+   |      value moved here
+   |
+help: consider restricting type parameter `T`
+   |
+LL | fn duplicate_tup1<T: Copy>(t: (T,)) -> ((T,), (T,)) {
+   |                    ++++++
+
+error[E0382]: use of moved value: `t`
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:14:9
+   |
+LL | fn duplicate_tup2<A, B>(t: (A, B)) -> ((A, B), (A, B)) {
+   |                         - move occurs because `t` has type `(A, B)`, which does not implement the `Copy` trait
+LL |     (t, t)
+   |      -  ^ value used here after move
+   |      |
+   |      value moved here
+   |
+help: consider restricting type parameters
+   |
+LL | fn duplicate_tup2<A: Copy, B: Copy>(t: (A, B)) -> ((A, B), (A, B)) {
+   |                    ++++++   ++++++
+
+error[E0382]: use of moved value: `t`
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:18:9
+   |
+LL | fn duplicate_custom<T>(t: S<T>) -> (S<T>, S<T>) {
+   |                        - move occurs because `t` has type `S<T>`, which does not implement the `Copy` trait
+LL |     (t, t)
+   |      -  ^ value used here after move
+   |      |
+   |      value moved here
+   |
+help: consider restricting type parameter `T`
+   |
+LL | fn duplicate_custom<T: Trait + Copy>(t: S<T>) -> (S<T>, S<T>) {
+   |                      ++++++++++++++
+
+error[E0382]: use of moved value: `t`
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:35:9
+   |
+LL | fn duplicate_custom_1<T>(t: S<T>) -> (S<T>, S<T>) where {
+   |                          - move occurs because `t` has type `S<T>`, which does not implement the `Copy` trait
+LL |     (t, t)
+   |      -  ^ value used here after move
+   |      |
+   |      value moved here
+   |
+help: consider restricting type parameter `T`
+   |
+LL | fn duplicate_custom_1<T: Trait + Copy>(t: S<T>) -> (S<T>, S<T>) where {
+   |                        ++++++++++++++
+
+error[E0382]: use of moved value: `t`
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:42:9
+   |
+LL | fn duplicate_custom_2<T>(t: S<T>) -> (S<T>, S<T>)
+   |                          - move occurs because `t` has type `S<T>`, which does not implement the `Copy` trait
+...
+LL |     (t, t)
+   |      -  ^ value used here after move
+   |      |
+   |      value moved here
+   |
+help: consider further restricting this bound
+   |
+LL |     T: A + Trait + Copy,
+   |          ++++++++++++++
+
+error[E0382]: use of moved value: `t`
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:50:9
+   |
+LL | fn duplicate_custom_3<T>(t: S<T>) -> (S<T>, S<T>)
+   |                          - move occurs because `t` has type `S<T>`, which does not implement the `Copy` trait
+...
+LL |     (t, t)
+   |      -  ^ value used here after move
+   |      |
+   |      value moved here
+   |
+help: consider further restricting type parameter `T`
+   |
+LL |     T: B, T: Trait, T: Copy
+   |         ~~~~~~~~~~~~~~~~~~~
+
+error[E0382]: use of moved value: `t`
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:57:9
+   |
+LL | fn duplicate_custom_4<T: A>(t: S<T>) -> (S<T>, S<T>)
+   |                             - move occurs because `t` has type `S<T>`, which does not implement the `Copy` trait
+...
+LL |     (t, t)
+   |      -  ^ value used here after move
+   |      |
+   |      value moved here
+   |
+help: consider further restricting this bound
+   |
+LL |     T: B + Trait + Copy,
+   |          ++++++++++++++
+
+error[E0382]: use of moved value: `t`
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:62:9
+   |
+LL | fn duplicate_rc<T>(t: std::rc::Rc<T>) -> (std::rc::Rc<T>, std::rc::Rc<T>) {
+   |                    - move occurs because `t` has type `Rc<T>`, which does not implement the `Copy` trait
+LL |     (t, t)
+   |      -  ^ value used here after move
+   |      |
+   |      value moved here
+
+error: aborting due to 10 previous errors
+
+For more information about this error, try `rustc --explain E0382`.

From f0a16b856011c8e63fac98fd6c127c2a0bbd532e Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Tue, 1 Mar 2022 14:11:42 +0300
Subject: [PATCH 07/16] Use rustfix in copy suggestion test

---
 .../use_of_moved_value_clone_suggestions.rs   |  6 ++
 ...se_of_moved_value_clone_suggestions.stderr | 13 ++++
 .../use_of_moved_value_copy_suggestions.fixed | 72 +++++++++++++++++++
 .../use_of_moved_value_copy_suggestions.rs    | 17 +++--
 ...use_of_moved_value_copy_suggestions.stderr | 36 +++++-----
 5 files changed, 119 insertions(+), 25 deletions(-)
 create mode 100644 src/test/ui/moves/use_of_moved_value_clone_suggestions.rs
 create mode 100644 src/test/ui/moves/use_of_moved_value_clone_suggestions.stderr
 create mode 100644 src/test/ui/moves/use_of_moved_value_copy_suggestions.fixed

diff --git a/src/test/ui/moves/use_of_moved_value_clone_suggestions.rs b/src/test/ui/moves/use_of_moved_value_clone_suggestions.rs
new file mode 100644
index 0000000000000..d5c8d4e6bdf2b
--- /dev/null
+++ b/src/test/ui/moves/use_of_moved_value_clone_suggestions.rs
@@ -0,0 +1,6 @@
+// `Rc` is not ever `Copy`, we should not suggest adding `T: Copy` constraint
+fn duplicate_rc<T>(t: std::rc::Rc<T>) -> (std::rc::Rc<T>, std::rc::Rc<T>) {
+    (t, t) //~ use of moved value: `t`
+}
+
+fn main() {}
diff --git a/src/test/ui/moves/use_of_moved_value_clone_suggestions.stderr b/src/test/ui/moves/use_of_moved_value_clone_suggestions.stderr
new file mode 100644
index 0000000000000..c25981e6f8063
--- /dev/null
+++ b/src/test/ui/moves/use_of_moved_value_clone_suggestions.stderr
@@ -0,0 +1,13 @@
+error[E0382]: use of moved value: `t`
+  --> $DIR/use_of_moved_value_clone_suggestions.rs:3:9
+   |
+LL | fn duplicate_rc<T>(t: std::rc::Rc<T>) -> (std::rc::Rc<T>, std::rc::Rc<T>) {
+   |                    - move occurs because `t` has type `Rc<T>`, which does not implement the `Copy` trait
+LL |     (t, t)
+   |      -  ^ value used here after move
+   |      |
+   |      value moved here
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0382`.
diff --git a/src/test/ui/moves/use_of_moved_value_copy_suggestions.fixed b/src/test/ui/moves/use_of_moved_value_copy_suggestions.fixed
new file mode 100644
index 0000000000000..d31046c77006e
--- /dev/null
+++ b/src/test/ui/moves/use_of_moved_value_copy_suggestions.fixed
@@ -0,0 +1,72 @@
+// run-rustfix
+#![allow(dead_code)]
+
+fn duplicate_t<T: Copy>(t: T) -> (T, T) {
+    //~^ HELP consider restricting type parameter `T`
+    (t, t) //~ use of moved value: `t`
+}
+
+fn duplicate_opt<T: Copy>(t: Option<T>) -> (Option<T>, Option<T>) {
+    //~^ HELP consider restricting type parameter `T`
+    (t, t) //~ use of moved value: `t`
+}
+
+fn duplicate_tup1<T: Copy>(t: (T,)) -> ((T,), (T,)) {
+    //~^ HELP consider restricting type parameter `T`
+    (t, t) //~ use of moved value: `t`
+}
+
+fn duplicate_tup2<A: Copy, B: Copy>(t: (A, B)) -> ((A, B), (A, B)) {
+    //~^ HELP consider restricting type parameters
+    (t, t) //~ use of moved value: `t`
+}
+
+fn duplicate_custom<T: Trait + Copy>(t: S<T>) -> (S<T>, S<T>) {
+    //~^ HELP consider restricting type parameter `T`
+    (t, t) //~ use of moved value: `t`
+}
+
+struct S<T>(T);
+trait Trait {}
+impl<T: Trait + Clone> Clone for S<T> {
+    fn clone(&self) -> Self {
+        Self(self.0.clone())
+    }
+}
+impl<T: Trait + Copy> Copy for S<T> {}
+
+trait A {}
+trait B {}
+
+// Test where bounds are added with different bound placements
+fn duplicate_custom_1<T: Trait + Copy>(t: S<T>) -> (S<T>, S<T>) where {
+    //~^ HELP consider restricting type parameter `T`
+    (t, t) //~ use of moved value: `t`
+}
+
+fn duplicate_custom_2<T>(t: S<T>) -> (S<T>, S<T>)
+where
+    T: A + Trait + Copy,
+    //~^ HELP consider further restricting this bound
+{
+    (t, t) //~ use of moved value: `t`
+}
+
+fn duplicate_custom_3<T>(t: S<T>) -> (S<T>, S<T>)
+where
+    T: A,
+    T: B, T: Trait, T: Copy
+    //~^ HELP consider further restricting type parameter `T`
+{
+    (t, t) //~ use of moved value: `t`
+}
+
+fn duplicate_custom_4<T: A>(t: S<T>) -> (S<T>, S<T>)
+where
+    T: B + Trait + Copy,
+    //~^ HELP consider further restricting this bound
+{
+    (t, t) //~ use of moved value: `t`
+}
+
+fn main() {}
diff --git a/src/test/ui/moves/use_of_moved_value_copy_suggestions.rs b/src/test/ui/moves/use_of_moved_value_copy_suggestions.rs
index 0930927c49d66..7cc5189fac017 100644
--- a/src/test/ui/moves/use_of_moved_value_copy_suggestions.rs
+++ b/src/test/ui/moves/use_of_moved_value_copy_suggestions.rs
@@ -1,20 +1,28 @@
+// run-rustfix
+#![allow(dead_code)]
+
 fn duplicate_t<T>(t: T) -> (T, T) {
+    //~^ HELP consider restricting type parameter `T`
     (t, t) //~ use of moved value: `t`
 }
 
 fn duplicate_opt<T>(t: Option<T>) -> (Option<T>, Option<T>) {
+    //~^ HELP consider restricting type parameter `T`
     (t, t) //~ use of moved value: `t`
 }
 
 fn duplicate_tup1<T>(t: (T,)) -> ((T,), (T,)) {
+    //~^ HELP consider restricting type parameter `T`
     (t, t) //~ use of moved value: `t`
 }
 
 fn duplicate_tup2<A, B>(t: (A, B)) -> ((A, B), (A, B)) {
+    //~^ HELP consider restricting type parameters
     (t, t) //~ use of moved value: `t`
 }
 
 fn duplicate_custom<T>(t: S<T>) -> (S<T>, S<T>) {
+    //~^ HELP consider restricting type parameter `T`
     (t, t) //~ use of moved value: `t`
 }
 
@@ -32,12 +40,14 @@ trait B {}
 
 // Test where bounds are added with different bound placements
 fn duplicate_custom_1<T>(t: S<T>) -> (S<T>, S<T>) where {
+    //~^ HELP consider restricting type parameter `T`
     (t, t) //~ use of moved value: `t`
 }
 
 fn duplicate_custom_2<T>(t: S<T>) -> (S<T>, S<T>)
 where
     T: A,
+    //~^ HELP consider further restricting this bound
 {
     (t, t) //~ use of moved value: `t`
 }
@@ -46,6 +56,7 @@ fn duplicate_custom_3<T>(t: S<T>) -> (S<T>, S<T>)
 where
     T: A,
     T: B,
+    //~^ HELP consider further restricting type parameter `T`
 {
     (t, t) //~ use of moved value: `t`
 }
@@ -53,13 +64,9 @@ where
 fn duplicate_custom_4<T: A>(t: S<T>) -> (S<T>, S<T>)
 where
     T: B,
+    //~^ HELP consider further restricting this bound
 {
     (t, t) //~ use of moved value: `t`
 }
 
-// `Rc` is not ever `Copy`, we should not suggest adding `T: Copy` constraint
-fn duplicate_rc<T>(t: std::rc::Rc<T>) -> (std::rc::Rc<T>, std::rc::Rc<T>) {
-    (t, t) //~ use of moved value: `t`
-}
-
 fn main() {}
diff --git a/src/test/ui/moves/use_of_moved_value_copy_suggestions.stderr b/src/test/ui/moves/use_of_moved_value_copy_suggestions.stderr
index c32ac2cd78aa0..8e72697ca30bb 100644
--- a/src/test/ui/moves/use_of_moved_value_copy_suggestions.stderr
+++ b/src/test/ui/moves/use_of_moved_value_copy_suggestions.stderr
@@ -1,8 +1,9 @@
 error[E0382]: use of moved value: `t`
-  --> $DIR/use_of_moved_value_copy_suggestions.rs:2:9
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:6:9
    |
 LL | fn duplicate_t<T>(t: T) -> (T, T) {
    |                   - move occurs because `t` has type `T`, which does not implement the `Copy` trait
+LL |
 LL |     (t, t)
    |      -  ^ value used here after move
    |      |
@@ -14,10 +15,11 @@ LL | fn duplicate_t<T: Copy>(t: T) -> (T, T) {
    |                 ++++++
 
 error[E0382]: use of moved value: `t`
-  --> $DIR/use_of_moved_value_copy_suggestions.rs:6:9
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:11:9
    |
 LL | fn duplicate_opt<T>(t: Option<T>) -> (Option<T>, Option<T>) {
    |                     - move occurs because `t` has type `Option<T>`, which does not implement the `Copy` trait
+LL |
 LL |     (t, t)
    |      -  ^ value used here after move
    |      |
@@ -29,10 +31,11 @@ LL | fn duplicate_opt<T: Copy>(t: Option<T>) -> (Option<T>, Option<T>) {
    |                   ++++++
 
 error[E0382]: use of moved value: `t`
-  --> $DIR/use_of_moved_value_copy_suggestions.rs:10:9
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:16:9
    |
 LL | fn duplicate_tup1<T>(t: (T,)) -> ((T,), (T,)) {
    |                      - move occurs because `t` has type `(T,)`, which does not implement the `Copy` trait
+LL |
 LL |     (t, t)
    |      -  ^ value used here after move
    |      |
@@ -44,10 +47,11 @@ LL | fn duplicate_tup1<T: Copy>(t: (T,)) -> ((T,), (T,)) {
    |                    ++++++
 
 error[E0382]: use of moved value: `t`
-  --> $DIR/use_of_moved_value_copy_suggestions.rs:14:9
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:21:9
    |
 LL | fn duplicate_tup2<A, B>(t: (A, B)) -> ((A, B), (A, B)) {
    |                         - move occurs because `t` has type `(A, B)`, which does not implement the `Copy` trait
+LL |
 LL |     (t, t)
    |      -  ^ value used here after move
    |      |
@@ -59,10 +63,11 @@ LL | fn duplicate_tup2<A: Copy, B: Copy>(t: (A, B)) -> ((A, B), (A, B)) {
    |                    ++++++   ++++++
 
 error[E0382]: use of moved value: `t`
-  --> $DIR/use_of_moved_value_copy_suggestions.rs:18:9
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:26:9
    |
 LL | fn duplicate_custom<T>(t: S<T>) -> (S<T>, S<T>) {
    |                        - move occurs because `t` has type `S<T>`, which does not implement the `Copy` trait
+LL |
 LL |     (t, t)
    |      -  ^ value used here after move
    |      |
@@ -74,10 +79,11 @@ LL | fn duplicate_custom<T: Trait + Copy>(t: S<T>) -> (S<T>, S<T>) {
    |                      ++++++++++++++
 
 error[E0382]: use of moved value: `t`
-  --> $DIR/use_of_moved_value_copy_suggestions.rs:35:9
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:44:9
    |
 LL | fn duplicate_custom_1<T>(t: S<T>) -> (S<T>, S<T>) where {
    |                          - move occurs because `t` has type `S<T>`, which does not implement the `Copy` trait
+LL |
 LL |     (t, t)
    |      -  ^ value used here after move
    |      |
@@ -89,7 +95,7 @@ LL | fn duplicate_custom_1<T: Trait + Copy>(t: S<T>) -> (S<T>, S<T>) where {
    |                        ++++++++++++++
 
 error[E0382]: use of moved value: `t`
-  --> $DIR/use_of_moved_value_copy_suggestions.rs:42:9
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:52:9
    |
 LL | fn duplicate_custom_2<T>(t: S<T>) -> (S<T>, S<T>)
    |                          - move occurs because `t` has type `S<T>`, which does not implement the `Copy` trait
@@ -105,7 +111,7 @@ LL |     T: A + Trait + Copy,
    |          ++++++++++++++
 
 error[E0382]: use of moved value: `t`
-  --> $DIR/use_of_moved_value_copy_suggestions.rs:50:9
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:61:9
    |
 LL | fn duplicate_custom_3<T>(t: S<T>) -> (S<T>, S<T>)
    |                          - move occurs because `t` has type `S<T>`, which does not implement the `Copy` trait
@@ -121,7 +127,7 @@ LL |     T: B, T: Trait, T: Copy
    |         ~~~~~~~~~~~~~~~~~~~
 
 error[E0382]: use of moved value: `t`
-  --> $DIR/use_of_moved_value_copy_suggestions.rs:57:9
+  --> $DIR/use_of_moved_value_copy_suggestions.rs:69:9
    |
 LL | fn duplicate_custom_4<T: A>(t: S<T>) -> (S<T>, S<T>)
    |                             - move occurs because `t` has type `S<T>`, which does not implement the `Copy` trait
@@ -136,16 +142,6 @@ help: consider further restricting this bound
 LL |     T: B + Trait + Copy,
    |          ++++++++++++++
 
-error[E0382]: use of moved value: `t`
-  --> $DIR/use_of_moved_value_copy_suggestions.rs:62:9
-   |
-LL | fn duplicate_rc<T>(t: std::rc::Rc<T>) -> (std::rc::Rc<T>, std::rc::Rc<T>) {
-   |                    - move occurs because `t` has type `Rc<T>`, which does not implement the `Copy` trait
-LL |     (t, t)
-   |      -  ^ value used here after move
-   |      |
-   |      value moved here
-
-error: aborting due to 10 previous errors
+error: aborting due to 9 previous errors
 
 For more information about this error, try `rustc --explain E0382`.

From 723d33462c79a3628ca4cf357044b3d5809e7a96 Mon Sep 17 00:00:00 2001
From: Josh Stone <jistone@redhat.com>
Date: Tue, 1 Mar 2022 11:42:10 -0800
Subject: [PATCH 08/16] Restore the local filter on mono item sorting

In `CodegenUnit::items_in_deterministic_order`, there's a comment that
only local HirIds should be taken into account, but #90408 removed the
`as_local` call that sets others to None. Restoring that check fixes the
s390x hangs seen in [RHBZ 2058803].

[RHBZ 2058803]: https://bugzilla.redhat.com/show_bug.cgi?id=2058803
---
 compiler/rustc_middle/src/mir/mono.rs | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/compiler/rustc_middle/src/mir/mono.rs b/compiler/rustc_middle/src/mir/mono.rs
index 892808386deef..13c325a14e402 100644
--- a/compiler/rustc_middle/src/mir/mono.rs
+++ b/compiler/rustc_middle/src/mir/mono.rs
@@ -7,6 +7,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
 use rustc_hir::ItemId;
+use rustc_index::vec::Idx;
 use rustc_query_system::ich::{NodeIdHashingMode, StableHashingContext};
 use rustc_session::config::OptLevel;
 use rustc_span::source_map::Span;
@@ -380,7 +381,7 @@ impl<'tcx> CodegenUnit<'tcx> {
                             // instances into account. The others don't matter for
                             // the codegen tests and can even make item order
                             // unstable.
-                            InstanceDef::Item(def) => Some(def.did.index.as_usize()),
+                            InstanceDef::Item(def) => def.did.as_local().map(Idx::index),
                             InstanceDef::VtableShim(..)
                             | InstanceDef::ReifyShim(..)
                             | InstanceDef::Intrinsic(..)
@@ -391,10 +392,8 @@ impl<'tcx> CodegenUnit<'tcx> {
                             | InstanceDef::CloneShim(..) => None,
                         }
                     }
-                    MonoItem::Static(def_id) => Some(def_id.index.as_usize()),
-                    MonoItem::GlobalAsm(item_id) => {
-                        Some(item_id.def_id.to_def_id().index.as_usize())
-                    }
+                    MonoItem::Static(def_id) => def_id.as_local().map(Idx::index),
+                    MonoItem::GlobalAsm(item_id) => Some(item_id.def_id.index()),
                 },
                 item.symbol_name(tcx),
             )

From f28786643e6ce7ec3104f96cd40a0baa8f8d3cac Mon Sep 17 00:00:00 2001
From: Edwin Amsler <EdwinGuy@GMail.com>
Date: Tue, 1 Mar 2022 15:47:11 -0600
Subject: [PATCH 09/16] Demote Windows XP to no_std only

Modify the tier 3 non-ARM targets to show the standard library will no longer build for these and there is no work being done to change that.
---
 src/doc/rustc/src/platform-support.md | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/doc/rustc/src/platform-support.md b/src/doc/rustc/src/platform-support.md
index d7e0b9d50f084..4c05818440b09 100644
--- a/src/doc/rustc/src/platform-support.md
+++ b/src/doc/rustc/src/platform-support.md
@@ -139,7 +139,7 @@ target | std | notes
 `armv7r-none-eabi` | * | Bare ARMv7-R
 `armv7r-none-eabihf` | * | Bare ARMv7-R, hardfloat
 `asmjs-unknown-emscripten` | ✓ | asm.js via Emscripten
-`i586-pc-windows-msvc` | ✓ | 32-bit Windows w/o SSE
+`i586-pc-windows-msvc` | * | 32-bit Windows w/o SSE
 `i586-unknown-linux-gnu` | ✓ | 32-bit Linux w/o SSE (kernel 4.4, glibc 2.23)
 `i586-unknown-linux-musl` | ✓ | 32-bit Linux w/o SSE, MUSL
 `i686-linux-android` | ✓ | 32-bit x86 Android
@@ -236,7 +236,7 @@ target | std | host | notes
 `hexagon-unknown-linux-musl` | ? |  |
 `i386-apple-ios` | ✓ |  | 32-bit x86 iOS
 `i686-apple-darwin` | ✓ | ✓ | 32-bit macOS (10.7+, Lion+)
-`i686-pc-windows-msvc` | ✓ |  | 32-bit Windows XP support
+`i686-pc-windows-msvc` | * |  | 32-bit Windows XP support
 `i686-unknown-haiku` | ✓ | ✓ | 32-bit Haiku
 `i686-unknown-netbsd` | ✓ | ✓ | NetBSD/i386 with SSE2
 [`i686-unknown-openbsd`](platform-support/openbsd.md) | ✓ | ✓ | 32-bit OpenBSD
@@ -283,7 +283,7 @@ target | std | host | notes
 [`wasm64-unknown-unknown`](platform-support/wasm64-unknown-unknown.md) | ? |  | WebAssembly
 `x86_64-apple-ios-macabi` | ✓ |  | Apple Catalyst on x86_64
 `x86_64-apple-tvos` | * | | x86 64-bit tvOS
-`x86_64-pc-windows-msvc` | ✓ |  | 64-bit Windows XP support
+`x86_64-pc-windows-msvc` | * |  | 64-bit Windows XP support
 `x86_64-sun-solaris` | ? |  | Deprecated target for 64-bit Solaris 10/11, illumos
 `x86_64-unknown-dragonfly` | ✓ | ✓ | 64-bit DragonFlyBSD
 `x86_64-unknown-haiku` | ✓ | ✓ | 64-bit Haiku

From 6a838e41bb9d8c24a621cb69efab4c99948fdcf1 Mon Sep 17 00:00:00 2001
From: Josh Stone <jistone@redhat.com>
Date: Tue, 1 Mar 2022 15:53:22 -0800
Subject: [PATCH 10/16] Use CHECK-DAG in
 codegen/debuginfo-generic-closure-env-names.rs

---
 .../debuginfo-generic-closure-env-names.rs     | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/test/codegen/debuginfo-generic-closure-env-names.rs b/src/test/codegen/debuginfo-generic-closure-env-names.rs
index ad59f740b567f..b29f8b4a029d0 100644
--- a/src/test/codegen/debuginfo-generic-closure-env-names.rs
+++ b/src/test/codegen/debuginfo-generic-closure-env-names.rs
@@ -3,7 +3,7 @@
 // of the enclosing functions don't get lost.
 //
 // Unfortunately, the order that debuginfo gets emitted into LLVM IR becomes a bit hard
-// to predict once async fns are involved.
+// to predict once async fns are involved, so DAG allows any order.
 //
 // Note that the test does not check async-fns when targeting MSVC because debuginfo for
 // those does not follow the enum-fallback encoding yet and thus is incomplete.
@@ -27,24 +27,24 @@
 // CHECK: ![[generic_async_block_NAMESPACE:[0-9]+]] = !DINamespace(name: "generic_async_block"
 
 // function_containing_closure<u32>()
-// NONMSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "{closure_env#0}<u32>", scope: ![[function_containing_closure_NAMESPACE]]
-// MSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "closure_env$0<u32>", scope: ![[function_containing_closure_NAMESPACE]]
+// NONMSVC-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: "{closure_env#0}<u32>", scope: ![[function_containing_closure_NAMESPACE]]
+// MSVC-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: "closure_env$0<u32>", scope: ![[function_containing_closure_NAMESPACE]]
 
 // generic_async_function<Foo>()
-// NONMSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "{async_fn_env#0}<debuginfo_generic_closure_env_names::Foo>", scope: ![[generic_async_function_NAMESPACE]]
+// NONMSVC-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: "{async_fn_env#0}<debuginfo_generic_closure_env_names::Foo>", scope: ![[generic_async_function_NAMESPACE]]
 
 // generic_async_function<u32>()
-// NONMSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "{async_fn_env#0}<u32>", scope: ![[generic_async_function_NAMESPACE]]
+// NONMSVC-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: "{async_fn_env#0}<u32>", scope: ![[generic_async_function_NAMESPACE]]
 
 // generic_async_block<Foo>()
-// NONMSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "{async_block_env#0}<debuginfo_generic_closure_env_names::Foo>", scope: ![[generic_async_block_NAMESPACE]]
+// NONMSVC-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: "{async_block_env#0}<debuginfo_generic_closure_env_names::Foo>", scope: ![[generic_async_block_NAMESPACE]]
 
 // generic_async_block<u32>()
-// NONMSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "{async_block_env#0}<u32>", scope: ![[generic_async_block_NAMESPACE]]
+// NONMSVC-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: "{async_block_env#0}<u32>", scope: ![[generic_async_block_NAMESPACE]]
 
 // function_containing_closure<Foo>()
-// NONMSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "{closure_env#0}<debuginfo_generic_closure_env_names::Foo>", scope: ![[function_containing_closure_NAMESPACE]]
-// MSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "closure_env$0<debuginfo_generic_closure_env_names::Foo>", scope: ![[function_containing_closure_NAMESPACE]]
+// NONMSVC-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: "{closure_env#0}<debuginfo_generic_closure_env_names::Foo>", scope: ![[function_containing_closure_NAMESPACE]]
+// MSVC-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: "closure_env$0<debuginfo_generic_closure_env_names::Foo>", scope: ![[function_containing_closure_NAMESPACE]]
 
 
 #![crate_type = "lib"]

From 6739299d18a16851140bc6b24b8eeae31e3d5878 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Tue, 1 Mar 2022 20:02:59 -0500
Subject: [PATCH 11/16] Miri/CTFE: properly treat overflow in (signed)
 division/rem as UB

---
 .../src/interpret/intrinsics.rs               | 12 ++------
 .../src/interpret/operator.rs                 | 18 +++++++-----
 .../rustc_middle/src/mir/interpret/error.rs   |  6 ++++
 .../rustc_mir_transform/src/const_prop.rs     | 11 +++++++-
 library/core/tests/num/wrapping.rs            | 10 +++++++
 src/test/ui/consts/const-int-unchecked.stderr |  4 +--
 .../issue-8460-const.noopt.stderr             | 28 +++++++++----------
 .../issue-8460-const.opt.stderr               | 28 +++++++++----------
 ...8460-const.opt_with_overflow_checks.stderr | 28 +++++++++----------
 .../ui/numbers-arithmetic/issue-8460-const.rs | 24 ++++++++--------
 10 files changed, 93 insertions(+), 76 deletions(-)

diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics.rs b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
index d6f856a6f0a70..bf7e811c76f8e 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
@@ -500,15 +500,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         // `x % y != 0` or `y == 0` or `x == T::MIN && y == -1`.
         // First, check x % y != 0 (or if that computation overflows).
         let (res, overflow, _ty) = self.overflowing_binary_op(BinOp::Rem, &a, &b)?;
-        if overflow || res.assert_bits(a.layout.size) != 0 {
-            // Then, check if `b` is -1, which is the "MIN / -1" case.
-            let minus1 = Scalar::from_int(-1, dest.layout.size);
-            let b_scalar = b.to_scalar().unwrap();
-            if b_scalar == minus1 {
-                throw_ub_format!("exact_div: result of dividing MIN by -1 cannot be represented")
-            } else {
-                throw_ub_format!("exact_div: {} cannot be divided by {} without remainder", a, b,)
-            }
+        assert!(!overflow); // All overflow is UB, so this should never return on overflow.
+        if res.assert_bits(a.layout.size) != 0 {
+            throw_ub_format!("exact_div: {} cannot be divided by {} without remainder", a, b)
         }
         // `Rem` says this is all right, so we can let `Div` do its job.
         self.binop_ignore_overflow(BinOp::Div, &a, &b, dest)
diff --git a/compiler/rustc_const_eval/src/interpret/operator.rs b/compiler/rustc_const_eval/src/interpret/operator.rs
index 48c90e1881a9a..079ce9f07b8e1 100644
--- a/compiler/rustc_const_eval/src/interpret/operator.rs
+++ b/compiler/rustc_const_eval/src/interpret/operator.rs
@@ -196,16 +196,20 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 _ => None,
             };
             if let Some(op) = op {
+                let l = self.sign_extend(l, left_layout) as i128;
                 let r = self.sign_extend(r, right_layout) as i128;
-                // We need a special check for overflowing remainder:
-                // "int_min % -1" overflows and returns 0, but after casting things to a larger int
-                // type it does *not* overflow nor give an unrepresentable result!
-                if bin_op == Rem {
-                    if r == -1 && l == (1 << (size.bits() - 1)) {
-                        return Ok((Scalar::from_int(0, size), true, left_layout.ty));
+
+                // We need a special check for overflowing Rem and Div since they are *UB*
+                // on overflow, which can happen with "int_min $OP -1".
+                if matches!(bin_op, Rem | Div) {
+                    if l == size.signed_int_min() && r == -1 {
+                        if bin_op == Rem {
+                            throw_ub!(RemainderOverflow)
+                        } else {
+                            throw_ub!(DivisionOverflow)
+                        }
                     }
                 }
-                let l = self.sign_extend(l, left_layout) as i128;
 
                 let (result, oflo) = op(l, r);
                 // This may be out-of-bounds for the result type, so we have to truncate ourselves.
diff --git a/compiler/rustc_middle/src/mir/interpret/error.rs b/compiler/rustc_middle/src/mir/interpret/error.rs
index 31468ce73bfc5..389d31ea0c472 100644
--- a/compiler/rustc_middle/src/mir/interpret/error.rs
+++ b/compiler/rustc_middle/src/mir/interpret/error.rs
@@ -233,6 +233,10 @@ pub enum UndefinedBehaviorInfo<'tcx> {
     DivisionByZero,
     /// Something was "remainded" by 0 (x % 0).
     RemainderByZero,
+    /// Signed division overflowed (INT_MIN / -1).
+    DivisionOverflow,
+    /// Signed remainder overflowed (INT_MIN % -1).
+    RemainderOverflow,
     /// Overflowing inbounds pointer arithmetic.
     PointerArithOverflow,
     /// Invalid metadata in a wide pointer (using `str` to avoid allocations).
@@ -310,6 +314,8 @@ impl fmt::Display for UndefinedBehaviorInfo<'_> {
             }
             DivisionByZero => write!(f, "dividing by zero"),
             RemainderByZero => write!(f, "calculating the remainder with a divisor of zero"),
+            DivisionOverflow => write!(f, "overflow in signed division (dividing MIN by -1)"),
+            RemainderOverflow => write!(f, "overflow in signed remainder (dividing MIN by -1)"),
             PointerArithOverflow => write!(f, "overflowing in-bounds pointer arithmetic"),
             InvalidMeta(msg) => write!(f, "invalid metadata in wide pointer: {}", msg),
             InvalidVtableDropFn(sig) => write!(
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index 6075f572a651c..b724b527c7dfb 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -1200,12 +1200,21 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
                             AssertKind::RemainderByZero(op) => {
                                 Some(AssertKind::RemainderByZero(eval_to_int(op)))
                             }
+                            AssertKind::Overflow(bin_op @ (BinOp::Div | BinOp::Rem), op1, op2) => {
+                                // Division overflow is *UB* in the MIR, and different than the
+                                // other overflow checks.
+                                Some(AssertKind::Overflow(
+                                    *bin_op,
+                                    eval_to_int(op1),
+                                    eval_to_int(op2),
+                                ))
+                            }
                             AssertKind::BoundsCheck { ref len, ref index } => {
                                 let len = eval_to_int(len);
                                 let index = eval_to_int(index);
                                 Some(AssertKind::BoundsCheck { len, index })
                             }
-                            // Overflow is are already covered by checks on the binary operators.
+                            // Remaining overflow errors are already covered by checks on the binary operators.
                             AssertKind::Overflow(..) | AssertKind::OverflowNeg(_) => None,
                             // Need proper const propagator for these.
                             _ => None,
diff --git a/library/core/tests/num/wrapping.rs b/library/core/tests/num/wrapping.rs
index c4fb321ef26cf..8ded139a1809f 100644
--- a/library/core/tests/num/wrapping.rs
+++ b/library/core/tests/num/wrapping.rs
@@ -308,3 +308,13 @@ fn wrapping_int_api() {
         }
     }
 }
+
+#[test]
+fn wrapping_const() {
+    // Specifically the wrapping behavior of division and remainder is subtle,
+    // see https://github.com/rust-lang/rust/pull/94512.
+    const _: () = {
+        assert!(i32::MIN.wrapping_div(-1) == i32::MIN);
+        assert!(i32::MIN.wrapping_rem(-1) == 0);
+    };
+}
diff --git a/src/test/ui/consts/const-int-unchecked.stderr b/src/test/ui/consts/const-int-unchecked.stderr
index 22e8c8dabc970..ad880d56d904d 100644
--- a/src/test/ui/consts/const-int-unchecked.stderr
+++ b/src/test/ui/consts/const-int-unchecked.stderr
@@ -266,7 +266,7 @@ error[E0080]: evaluation of constant value failed
   --> $DIR/const-int-unchecked.rs:134:25
    |
 LL | const _: i32 = unsafe { std::intrinsics::unchecked_div(i32::MIN, -1) };
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow executing `unchecked_div`
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow in signed division (dividing MIN by -1)
 
 error[E0080]: evaluation of constant value failed
   --> $DIR/const-int-unchecked.rs:137:25
@@ -278,7 +278,7 @@ error[E0080]: evaluation of constant value failed
   --> $DIR/const-int-unchecked.rs:139:25
    |
 LL | const _: i32 = unsafe { std::intrinsics::unchecked_rem(i32::MIN, -1) };
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow executing `unchecked_rem`
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow in signed remainder (dividing MIN by -1)
 
 error[E0080]: evaluation of constant value failed
   --> $DIR/const-int-unchecked.rs:144:25
diff --git a/src/test/ui/numbers-arithmetic/issue-8460-const.noopt.stderr b/src/test/ui/numbers-arithmetic/issue-8460-const.noopt.stderr
index d94c7742de301..e2eee1ccdc98c 100644
--- a/src/test/ui/numbers-arithmetic/issue-8460-const.noopt.stderr
+++ b/src/test/ui/numbers-arithmetic/issue-8460-const.noopt.stderr
@@ -1,36 +1,36 @@
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:13:36
    |
 LL |     assert!(thread::spawn(move|| { isize::MIN / -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^^^ attempt to compute `isize::MIN / -1_isize`, which would overflow
    |
-   = note: `#[deny(arithmetic_overflow)]` on by default
+   = note: `#[deny(unconditional_panic)]` on by default
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:15:36
    |
 LL |     assert!(thread::spawn(move|| { i8::MIN / -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^ attempt to compute `i8::MIN / -1_i8`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:17:36
    |
 LL |     assert!(thread::spawn(move|| { i16::MIN / -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute `i16::MIN / -1_i16`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:19:36
    |
 LL |     assert!(thread::spawn(move|| { i32::MIN / -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute `i32::MIN / -1_i32`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:21:36
    |
 LL |     assert!(thread::spawn(move|| { i64::MIN / -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute `i64::MIN / -1_i64`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:23:36
    |
 LL |     assert!(thread::spawn(move|| { i128::MIN / -1; }).join().is_err());
@@ -41,8 +41,6 @@ error: this operation will panic at runtime
    |
 LL |     assert!(thread::spawn(move|| { 1isize / 0; }).join().is_err());
    |                                    ^^^^^^^^^^ attempt to divide `1_isize` by zero
-   |
-   = note: `#[deny(unconditional_panic)]` on by default
 
 error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:27:36
@@ -74,37 +72,37 @@ error: this operation will panic at runtime
 LL |     assert!(thread::spawn(move|| { 1i128 / 0; }).join().is_err());
    |                                    ^^^^^^^^^ attempt to divide `1_i128` by zero
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:37:36
    |
 LL |     assert!(thread::spawn(move|| { isize::MIN % -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^^^ attempt to compute the remainder of `isize::MIN % -1_isize`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:39:36
    |
 LL |     assert!(thread::spawn(move|| { i8::MIN % -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^ attempt to compute the remainder of `i8::MIN % -1_i8`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:41:36
    |
 LL |     assert!(thread::spawn(move|| { i16::MIN % -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute the remainder of `i16::MIN % -1_i16`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:43:36
    |
 LL |     assert!(thread::spawn(move|| { i32::MIN % -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute the remainder of `i32::MIN % -1_i32`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:45:36
    |
 LL |     assert!(thread::spawn(move|| { i64::MIN % -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute the remainder of `i64::MIN % -1_i64`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:47:36
    |
 LL |     assert!(thread::spawn(move|| { i128::MIN % -1; }).join().is_err());
diff --git a/src/test/ui/numbers-arithmetic/issue-8460-const.opt.stderr b/src/test/ui/numbers-arithmetic/issue-8460-const.opt.stderr
index d94c7742de301..e2eee1ccdc98c 100644
--- a/src/test/ui/numbers-arithmetic/issue-8460-const.opt.stderr
+++ b/src/test/ui/numbers-arithmetic/issue-8460-const.opt.stderr
@@ -1,36 +1,36 @@
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:13:36
    |
 LL |     assert!(thread::spawn(move|| { isize::MIN / -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^^^ attempt to compute `isize::MIN / -1_isize`, which would overflow
    |
-   = note: `#[deny(arithmetic_overflow)]` on by default
+   = note: `#[deny(unconditional_panic)]` on by default
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:15:36
    |
 LL |     assert!(thread::spawn(move|| { i8::MIN / -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^ attempt to compute `i8::MIN / -1_i8`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:17:36
    |
 LL |     assert!(thread::spawn(move|| { i16::MIN / -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute `i16::MIN / -1_i16`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:19:36
    |
 LL |     assert!(thread::spawn(move|| { i32::MIN / -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute `i32::MIN / -1_i32`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:21:36
    |
 LL |     assert!(thread::spawn(move|| { i64::MIN / -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute `i64::MIN / -1_i64`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:23:36
    |
 LL |     assert!(thread::spawn(move|| { i128::MIN / -1; }).join().is_err());
@@ -41,8 +41,6 @@ error: this operation will panic at runtime
    |
 LL |     assert!(thread::spawn(move|| { 1isize / 0; }).join().is_err());
    |                                    ^^^^^^^^^^ attempt to divide `1_isize` by zero
-   |
-   = note: `#[deny(unconditional_panic)]` on by default
 
 error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:27:36
@@ -74,37 +72,37 @@ error: this operation will panic at runtime
 LL |     assert!(thread::spawn(move|| { 1i128 / 0; }).join().is_err());
    |                                    ^^^^^^^^^ attempt to divide `1_i128` by zero
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:37:36
    |
 LL |     assert!(thread::spawn(move|| { isize::MIN % -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^^^ attempt to compute the remainder of `isize::MIN % -1_isize`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:39:36
    |
 LL |     assert!(thread::spawn(move|| { i8::MIN % -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^ attempt to compute the remainder of `i8::MIN % -1_i8`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:41:36
    |
 LL |     assert!(thread::spawn(move|| { i16::MIN % -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute the remainder of `i16::MIN % -1_i16`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:43:36
    |
 LL |     assert!(thread::spawn(move|| { i32::MIN % -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute the remainder of `i32::MIN % -1_i32`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:45:36
    |
 LL |     assert!(thread::spawn(move|| { i64::MIN % -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute the remainder of `i64::MIN % -1_i64`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:47:36
    |
 LL |     assert!(thread::spawn(move|| { i128::MIN % -1; }).join().is_err());
diff --git a/src/test/ui/numbers-arithmetic/issue-8460-const.opt_with_overflow_checks.stderr b/src/test/ui/numbers-arithmetic/issue-8460-const.opt_with_overflow_checks.stderr
index d94c7742de301..e2eee1ccdc98c 100644
--- a/src/test/ui/numbers-arithmetic/issue-8460-const.opt_with_overflow_checks.stderr
+++ b/src/test/ui/numbers-arithmetic/issue-8460-const.opt_with_overflow_checks.stderr
@@ -1,36 +1,36 @@
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:13:36
    |
 LL |     assert!(thread::spawn(move|| { isize::MIN / -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^^^ attempt to compute `isize::MIN / -1_isize`, which would overflow
    |
-   = note: `#[deny(arithmetic_overflow)]` on by default
+   = note: `#[deny(unconditional_panic)]` on by default
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:15:36
    |
 LL |     assert!(thread::spawn(move|| { i8::MIN / -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^ attempt to compute `i8::MIN / -1_i8`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:17:36
    |
 LL |     assert!(thread::spawn(move|| { i16::MIN / -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute `i16::MIN / -1_i16`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:19:36
    |
 LL |     assert!(thread::spawn(move|| { i32::MIN / -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute `i32::MIN / -1_i32`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:21:36
    |
 LL |     assert!(thread::spawn(move|| { i64::MIN / -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute `i64::MIN / -1_i64`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:23:36
    |
 LL |     assert!(thread::spawn(move|| { i128::MIN / -1; }).join().is_err());
@@ -41,8 +41,6 @@ error: this operation will panic at runtime
    |
 LL |     assert!(thread::spawn(move|| { 1isize / 0; }).join().is_err());
    |                                    ^^^^^^^^^^ attempt to divide `1_isize` by zero
-   |
-   = note: `#[deny(unconditional_panic)]` on by default
 
 error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:27:36
@@ -74,37 +72,37 @@ error: this operation will panic at runtime
 LL |     assert!(thread::spawn(move|| { 1i128 / 0; }).join().is_err());
    |                                    ^^^^^^^^^ attempt to divide `1_i128` by zero
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:37:36
    |
 LL |     assert!(thread::spawn(move|| { isize::MIN % -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^^^ attempt to compute the remainder of `isize::MIN % -1_isize`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:39:36
    |
 LL |     assert!(thread::spawn(move|| { i8::MIN % -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^ attempt to compute the remainder of `i8::MIN % -1_i8`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:41:36
    |
 LL |     assert!(thread::spawn(move|| { i16::MIN % -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute the remainder of `i16::MIN % -1_i16`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:43:36
    |
 LL |     assert!(thread::spawn(move|| { i32::MIN % -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute the remainder of `i32::MIN % -1_i32`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:45:36
    |
 LL |     assert!(thread::spawn(move|| { i64::MIN % -1; }).join().is_err());
    |                                    ^^^^^^^^^^^^^ attempt to compute the remainder of `i64::MIN % -1_i64`, which would overflow
 
-error: this arithmetic operation will overflow
+error: this operation will panic at runtime
   --> $DIR/issue-8460-const.rs:47:36
    |
 LL |     assert!(thread::spawn(move|| { i128::MIN % -1; }).join().is_err());
diff --git a/src/test/ui/numbers-arithmetic/issue-8460-const.rs b/src/test/ui/numbers-arithmetic/issue-8460-const.rs
index dc754666c8e1f..8cad6deb3db5e 100644
--- a/src/test/ui/numbers-arithmetic/issue-8460-const.rs
+++ b/src/test/ui/numbers-arithmetic/issue-8460-const.rs
@@ -11,17 +11,17 @@ use std::thread;
 
 fn main() {
     assert!(thread::spawn(move|| { isize::MIN / -1; }).join().is_err());
-    //~^ ERROR arithmetic operation will overflow
+    //~^ ERROR operation will panic
     assert!(thread::spawn(move|| { i8::MIN / -1; }).join().is_err());
-    //~^ ERROR arithmetic operation will overflow
+    //~^ ERROR operation will panic
     assert!(thread::spawn(move|| { i16::MIN / -1; }).join().is_err());
-    //~^ ERROR arithmetic operation will overflow
+    //~^ ERROR operation will panic
     assert!(thread::spawn(move|| { i32::MIN / -1; }).join().is_err());
-    //~^ ERROR arithmetic operation will overflow
+    //~^ ERROR operation will panic
     assert!(thread::spawn(move|| { i64::MIN / -1; }).join().is_err());
-    //~^ ERROR arithmetic operation will overflow
+    //~^ ERROR operation will panic
     assert!(thread::spawn(move|| { i128::MIN / -1; }).join().is_err());
-    //~^ ERROR arithmetic operation will overflow
+    //~^ ERROR operation will panic
     assert!(thread::spawn(move|| { 1isize / 0; }).join().is_err());
     //~^ ERROR operation will panic
     assert!(thread::spawn(move|| { 1i8 / 0; }).join().is_err());
@@ -35,17 +35,17 @@ fn main() {
     assert!(thread::spawn(move|| { 1i128 / 0; }).join().is_err());
     //~^ ERROR operation will panic
     assert!(thread::spawn(move|| { isize::MIN % -1; }).join().is_err());
-    //~^ ERROR arithmetic operation will overflow
+    //~^ ERROR operation will panic
     assert!(thread::spawn(move|| { i8::MIN % -1; }).join().is_err());
-    //~^ ERROR arithmetic operation will overflow
+    //~^ ERROR operation will panic
     assert!(thread::spawn(move|| { i16::MIN % -1; }).join().is_err());
-    //~^ ERROR arithmetic operation will overflow
+    //~^ ERROR operation will panic
     assert!(thread::spawn(move|| { i32::MIN % -1; }).join().is_err());
-    //~^ ERROR arithmetic operation will overflow
+    //~^ ERROR operation will panic
     assert!(thread::spawn(move|| { i64::MIN % -1; }).join().is_err());
-    //~^ ERROR arithmetic operation will overflow
+    //~^ ERROR operation will panic
     assert!(thread::spawn(move|| { i128::MIN % -1; }).join().is_err());
-    //~^ ERROR arithmetic operation will overflow
+    //~^ ERROR operation will panic
     assert!(thread::spawn(move|| { 1isize % 0; }).join().is_err());
     //~^ ERROR operation will panic
     assert!(thread::spawn(move|| { 1i8 % 0; }).join().is_err());

From 3768f0b813cd6944b0893b76bc0add776eb8cae0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Marie?= <semarie@online.fr>
Date: Wed, 2 Mar 2022 10:33:50 +0000
Subject: [PATCH 12/16] update char signess for openbsd

adds more archs for openbsd: arm, mips64, powerpc, powerpc64, and riscv64.
---
 library/core/src/ffi/mod.rs | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/library/core/src/ffi/mod.rs b/library/core/src/ffi/mod.rs
index e5255686ff984..81f04994c6f8d 100644
--- a/library/core/src/ffi/mod.rs
+++ b/library/core/src/ffi/mod.rs
@@ -130,7 +130,16 @@ mod c_char_definition {
                 target_os = "netbsd",
                 any(target_arch = "aarch64", target_arch = "arm", target_arch = "powerpc")
             ),
-            all(target_os = "openbsd", target_arch = "aarch64"),
+            all(
+                target_os = "openbsd",
+                any(
+                    target_arch = "aarch64",
+                    target_arch = "arm",
+                    target_arch = "powerpc",
+                    target_arch = "powerpc64",
+                    target_arch = "riscv64",
+                ),
+            ),
             all(
                 target_os = "vxworks",
                 any(

From fa8e1bedd34d85d4cbe83b8c61a53d080a83e72d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Marie?= <semarie@online.fr>
Date: Wed, 2 Mar 2022 12:12:28 +0000
Subject: [PATCH 13/16] merge the char signess list of archs with freebsd as it
 is the same

---
 library/core/src/ffi/mod.rs | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/library/core/src/ffi/mod.rs b/library/core/src/ffi/mod.rs
index 81f04994c6f8d..2b611e5aae276 100644
--- a/library/core/src/ffi/mod.rs
+++ b/library/core/src/ffi/mod.rs
@@ -117,7 +117,7 @@ mod c_char_definition {
             all(target_os = "android", any(target_arch = "aarch64", target_arch = "arm")),
             all(target_os = "l4re", target_arch = "x86_64"),
             all(
-                target_os = "freebsd",
+                any(target_os = "freebsd", target_os = "openbsd"),
                 any(
                     target_arch = "aarch64",
                     target_arch = "arm",
@@ -130,16 +130,6 @@ mod c_char_definition {
                 target_os = "netbsd",
                 any(target_arch = "aarch64", target_arch = "arm", target_arch = "powerpc")
             ),
-            all(
-                target_os = "openbsd",
-                any(
-                    target_arch = "aarch64",
-                    target_arch = "arm",
-                    target_arch = "powerpc",
-                    target_arch = "powerpc64",
-                    target_arch = "riscv64",
-                ),
-            ),
             all(
                 target_os = "vxworks",
                 any(

From 003c892f9f5bdb8b19f27e75e9d89d148ce030e8 Mon Sep 17 00:00:00 2001
From: Mara Bos <m-ou.se@m-ou.se>
Date: Wed, 19 Jan 2022 13:11:26 +0100
Subject: [PATCH 14/16] Fix Ok(()) suggestion when desugaring is involved.

---
 compiler/rustc_typeck/src/check/demand.rs | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/compiler/rustc_typeck/src/check/demand.rs b/compiler/rustc_typeck/src/check/demand.rs
index 3b644099ecf04..501ff2e3850be 100644
--- a/compiler/rustc_typeck/src/check/demand.rs
+++ b/compiler/rustc_typeck/src/check/demand.rs
@@ -276,11 +276,28 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // we suggest adding a separate return expression instead.
             // (To avoid things like suggesting `Ok(while .. { .. })`.)
             if expr_ty.is_unit() {
+                let mut id = expr.hir_id;
+                let mut parent;
+
+                // Unroll desugaring, to make sure this works for `for` loops etc.
+                loop {
+                    parent = self.tcx.hir().get_parent_node(id);
+                    if let Some(parent_span) = self.tcx.hir().opt_span(parent) {
+                        if parent_span.find_ancestor_inside(expr.span).is_some() {
+                            // The parent node is part of the same span, so is the result of the
+                            // same expansion/desugaring and not the 'real' parent node.
+                            id = parent;
+                            continue;
+                        }
+                    }
+                    break;
+                }
+
                 if let Some(hir::Node::Block(&hir::Block {
                     span: block_span, expr: Some(e), ..
-                })) = self.tcx.hir().find(self.tcx.hir().get_parent_node(expr.hir_id))
+                })) = self.tcx.hir().find(parent)
                 {
-                    if e.hir_id == expr.hir_id {
+                    if e.hir_id == id {
                         if let Some(span) = expr.span.find_ancestor_inside(block_span) {
                             let return_suggestions =
                                 if self.tcx.is_diagnostic_item(sym::Result, expected_adt.did) {

From 85cc4710efe60ce52781a40fab82860c1b81070b Mon Sep 17 00:00:00 2001
From: Mara Bos <m-ou.se@m-ou.se>
Date: Wed, 19 Jan 2022 13:11:48 +0100
Subject: [PATCH 15/16] Add more tests for mismatched Option/Result return
 types.

---
 .../ui/did_you_mean/compatible-variants.rs    | 15 +++++
 .../did_you_mean/compatible-variants.stderr   | 61 ++++++++++++++++---
 2 files changed, 68 insertions(+), 8 deletions(-)

diff --git a/src/test/ui/did_you_mean/compatible-variants.rs b/src/test/ui/did_you_mean/compatible-variants.rs
index a70dda8386f08..b078064b26745 100644
--- a/src/test/ui/did_you_mean/compatible-variants.rs
+++ b/src/test/ui/did_you_mean/compatible-variants.rs
@@ -23,6 +23,21 @@ fn b() -> Result<(), ()> {
     //~| HELP try adding an expression
 }
 
+fn c() -> Option<()> {
+    for _ in [1, 2] {
+        //~^ ERROR mismatched types
+        f();
+    }
+    //~^ HELP try adding an expression
+}
+
+fn d() -> Option<()> {
+    c()?
+    //~^ ERROR incompatible types
+    //~| HELP try removing this `?`
+    //~| HELP try adding an expression
+}
+
 fn main() {
     let _: Option<()> = while false {};
     //~^ ERROR mismatched types
diff --git a/src/test/ui/did_you_mean/compatible-variants.stderr b/src/test/ui/did_you_mean/compatible-variants.stderr
index 0dfd8f5c128f6..51c1bf97c4e2c 100644
--- a/src/test/ui/did_you_mean/compatible-variants.stderr
+++ b/src/test/ui/did_you_mean/compatible-variants.stderr
@@ -37,7 +37,52 @@ LL +     Ok(())
    |
 
 error[E0308]: mismatched types
-  --> $DIR/compatible-variants.rs:27:25
+  --> $DIR/compatible-variants.rs:27:5
+   |
+LL |   fn c() -> Option<()> {
+   |             ---------- expected `Option<()>` because of return type
+LL | /     for _ in [1, 2] {
+LL | |
+LL | |         f();
+LL | |     }
+   | |_____^ expected enum `Option`, found `()`
+   |
+   = note:   expected enum `Option<()>`
+           found unit type `()`
+help: try adding an expression at the end of the block
+   |
+LL ~     }
+LL +     None
+   |
+LL ~     }
+LL +     Some(())
+   |
+
+error[E0308]: `?` operator has incompatible types
+  --> $DIR/compatible-variants.rs:35:5
+   |
+LL |     c()?
+   |     ^^^^ expected enum `Option`, found `()`
+   |
+   = note: `?` operator cannot convert from `()` to `Option<()>`
+   = note:   expected enum `Option<()>`
+           found unit type `()`
+help: try removing this `?`
+   |
+LL -     c()?
+LL +     c()
+   | 
+help: try adding an expression at the end of the block
+   |
+LL ~     c()?;
+LL +     None
+   |
+LL ~     c()?;
+LL +     Some(())
+   |
+
+error[E0308]: mismatched types
+  --> $DIR/compatible-variants.rs:42:25
    |
 LL |     let _: Option<()> = while false {};
    |            ----------   ^^^^^^^^^^^^^^ expected enum `Option`, found `()`
@@ -52,7 +97,7 @@ LL |     let _: Option<()> = Some(while false {});
    |                         +++++              +
 
 error[E0308]: mismatched types
-  --> $DIR/compatible-variants.rs:31:9
+  --> $DIR/compatible-variants.rs:46:9
    |
 LL |         while false {}
    |         ^^^^^^^^^^^^^^ expected enum `Option`, found `()`
@@ -69,7 +114,7 @@ LL +         Some(())
    |
 
 error[E0308]: mismatched types
-  --> $DIR/compatible-variants.rs:35:31
+  --> $DIR/compatible-variants.rs:50:31
    |
 LL |     let _: Result<i32, i32> = 1;
    |            ----------------   ^ expected enum `Result`, found integer
@@ -86,7 +131,7 @@ LL |     let _: Result<i32, i32> = Err(1);
    |                               ++++ +
 
 error[E0308]: mismatched types
-  --> $DIR/compatible-variants.rs:38:26
+  --> $DIR/compatible-variants.rs:53:26
    |
 LL |     let _: Option<i32> = 1;
    |            -----------   ^ expected enum `Option`, found integer
@@ -101,7 +146,7 @@ LL |     let _: Option<i32> = Some(1);
    |                          +++++ +
 
 error[E0308]: mismatched types
-  --> $DIR/compatible-variants.rs:41:28
+  --> $DIR/compatible-variants.rs:56:28
    |
 LL |     let _: Hey<i32, i32> = 1;
    |            -------------   ^ expected enum `Hey`, found integer
@@ -118,7 +163,7 @@ LL |     let _: Hey<i32, i32> = Hey::B(1);
    |                            +++++++ +
 
 error[E0308]: mismatched types
-  --> $DIR/compatible-variants.rs:44:29
+  --> $DIR/compatible-variants.rs:59:29
    |
 LL |     let _: Hey<i32, bool> = false;
    |            --------------   ^^^^^ expected enum `Hey`, found `bool`
@@ -133,7 +178,7 @@ LL |     let _: Hey<i32, bool> = Hey::B(false);
    |                             +++++++     +
 
 error[E0308]: mismatched types
-  --> $DIR/compatible-variants.rs:48:19
+  --> $DIR/compatible-variants.rs:63:19
    |
 LL |     let _ = Foo { bar };
    |                   ^^^ expected enum `Option`, found `i32`
@@ -145,6 +190,6 @@ help: try wrapping the expression in `Some`
 LL |     let _ = Foo { bar: Some(bar) };
    |                   ++++++++++   +
 
-error: aborting due to 9 previous errors
+error: aborting due to 11 previous errors
 
 For more information about this error, try `rustc --explain E0308`.

From b32cabf458a67bdf6b511d385a315d23547dd157 Mon Sep 17 00:00:00 2001
From: Mara Bos <m-ou.se@m-ou.se>
Date: Wed, 2 Mar 2022 19:30:25 +0100
Subject: [PATCH 16/16] Update test output.

---
 src/test/ui/async-await/proper-span-for-type-error.fixed  | 3 ++-
 src/test/ui/async-await/proper-span-for-type-error.stderr | 7 ++++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/test/ui/async-await/proper-span-for-type-error.fixed b/src/test/ui/async-await/proper-span-for-type-error.fixed
index 1f1e1184dcc02..7d43b575d2f66 100644
--- a/src/test/ui/async-await/proper-span-for-type-error.fixed
+++ b/src/test/ui/async-await/proper-span-for-type-error.fixed
@@ -5,7 +5,8 @@
 async fn a() {}
 
 async fn foo() -> Result<(), i32> {
-    Ok(a().await) //~ ERROR mismatched types
+    a().await;
+    Ok(()) //~ ERROR mismatched types
 }
 
 fn main() {}
diff --git a/src/test/ui/async-await/proper-span-for-type-error.stderr b/src/test/ui/async-await/proper-span-for-type-error.stderr
index 611dc0407bf96..25f05156ce2bc 100644
--- a/src/test/ui/async-await/proper-span-for-type-error.stderr
+++ b/src/test/ui/async-await/proper-span-for-type-error.stderr
@@ -6,10 +6,11 @@ LL |     a().await
    |
    = note:   expected enum `Result<(), i32>`
            found unit type `()`
-help: try wrapping the expression in `Ok`
+help: try adding an expression at the end of the block
+   |
+LL ~     a().await;
+LL ~     Ok(())
    |
-LL |     Ok(a().await)
-   |     +++         +
 
 error: aborting due to previous error