From 18df8d6e559174700e302369c2fe0d9c7c143e66 Mon Sep 17 00:00:00 2001
From: Kevin Reid <kpreid@google.com>
Date: Mon, 30 Aug 2021 20:20:14 -0700
Subject: [PATCH 01/15] Expand documentation for `FpCategory`.

I intend these changes to be helpful to readers who are not yet familiar
with the quirks of floating-point numbers. Additionally, I felt it was
misleading to describe `Nan` as being the result of division by zero,
since most divisions by zero (except for 0/0) produce `Infinite` floats,
so I moved that remark to the `Infinite` variant with adjustment.

The first sentence of the `Nan` documentation is copied from `f32`;
I followed the example of the `f64` documentation by referring to `f32`
for general concepts, rather than duplicating the text.
---
 library/core/src/num/mod.rs | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/library/core/src/num/mod.rs b/library/core/src/num/mod.rs
index 09b7418bec0d9..360ca9b700b7a 100644
--- a/library/core/src/num/mod.rs
+++ b/library/core/src/num/mod.rs
@@ -778,23 +778,41 @@ impl usize {
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub enum FpCategory {
-    /// "Not a Number", often obtained by dividing by zero.
+    /// NaN (not a number): this value results from calculations like `(-1.0).sqrt()`.
+    ///
+    /// See [the documentation for `f32`](f32) for more information on the unusual properties
+    /// of NaN.
     #[stable(feature = "rust1", since = "1.0.0")]
     Nan,
 
-    /// Positive or negative infinity.
+    /// Positive or negative infinity, which often results from dividing a nonzero number
+    /// by zero.
     #[stable(feature = "rust1", since = "1.0.0")]
     Infinite,
 
     /// Positive or negative zero.
+    ///
+    /// See [the documentation for `f32`](f32) for more information on the signedness of zeroes.
     #[stable(feature = "rust1", since = "1.0.0")]
     Zero,
 
-    /// De-normalized floating point representation (less precise than `Normal`).
+    /// “Subnormal” or “denormal” floating point representation (less precise, relative to
+    /// their magnitude, than [`Normal`]).
+    ///
+    /// Subnormal numbers are larger in magnitude than [`Zero`] but smaller in magnitude than all
+    /// [`Normal`] numbers.
+    ///
+    /// [`Normal`]: Self::Normal
+    /// [`Zero`]: Self::Zero
     #[stable(feature = "rust1", since = "1.0.0")]
     Subnormal,
 
-    /// A regular floating point number.
+    /// A regular floating point number, not any of the exceptional categories.
+    ///
+    /// The smallest positive normal numbers are [`f32::MIN_POSITIVE`] and [`f64::MIN_POSITIVE`],
+    /// and the largest positive normal numbers are [`f32::MAX`] and [`f64::MAX`]. (Unlike signed
+    /// integers, floating point numbers are symmetric in their range, so negating any of these
+    /// constants will produce their negative counterpart.)
     #[stable(feature = "rust1", since = "1.0.0")]
     Normal,
 }

From 25b6f9b68b6ff4bdcce01feaa5259ff2786c4851 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tomasz=20Mi=C4=85sko?= <tomasz.miasko@gmail.com>
Date: Tue, 28 Sep 2021 00:00:00 +0000
Subject: [PATCH 02/15] print-type-sizes: skip field printing for primitives

---
 compiler/rustc_middle/src/ty/layout.rs          | 7 +++++--
 src/test/ui/print_type_sizes/uninhabited.rs     | 2 +-
 src/test/ui/print_type_sizes/uninhabited.stdout | 1 +
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs
index cfbbec374a172..2c3c21e7a393b 100644
--- a/compiler/rustc_middle/src/ty/layout.rs
+++ b/compiler/rustc_middle/src/ty/layout.rs
@@ -1805,8 +1805,11 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
 
         match layout.variants {
             Variants::Single { index } => {
-                debug!("print-type-size `{:#?}` variant {}", layout, adt_def.variants[index].ident);
-                if !adt_def.variants.is_empty() {
+                if !adt_def.variants.is_empty() && layout.fields != FieldsShape::Primitive {
+                    debug!(
+                        "print-type-size `{:#?}` variant {}",
+                        layout, adt_def.variants[index].ident
+                    );
                     let variant_def = &adt_def.variants[index];
                     let fields: Vec<_> = variant_def.fields.iter().map(|f| f.ident.name).collect();
                     record(
diff --git a/src/test/ui/print_type_sizes/uninhabited.rs b/src/test/ui/print_type_sizes/uninhabited.rs
index c234547bd14b1..06a62db4ebb0f 100644
--- a/src/test/ui/print_type_sizes/uninhabited.rs
+++ b/src/test/ui/print_type_sizes/uninhabited.rs
@@ -11,5 +11,5 @@
 fn start(_: isize, _: *const *const u8) -> isize {
     let _x: Option<!> = None;
     let _y: Result<u32, !> = Ok(42);
-    0
+    let _z: Result<!, !> = loop {};
 }
diff --git a/src/test/ui/print_type_sizes/uninhabited.stdout b/src/test/ui/print_type_sizes/uninhabited.stdout
index 2a8706f7ac551..5eb5384bce340 100644
--- a/src/test/ui/print_type_sizes/uninhabited.stdout
+++ b/src/test/ui/print_type_sizes/uninhabited.stdout
@@ -3,3 +3,4 @@ print-type-size     variant `Ok`: 4 bytes
 print-type-size         field `.0`: 4 bytes
 print-type-size type: `std::option::Option<!>`: 0 bytes, alignment: 1 bytes
 print-type-size     variant `None`: 0 bytes
+print-type-size type: `std::result::Result<!, !>`: 0 bytes, alignment: 1 bytes

From fe11483afa90628106971993049b4fd2f0dae6fc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20du=20Garreau?= <bdgdlm@outlook.com>
Date: Thu, 29 Jul 2021 19:39:56 +0200
Subject: [PATCH 03/15] Add functions to add unsigned and signed integers

---
 library/core/src/lib.rs             |   1 +
 library/core/src/num/mod.rs         |  16 ++---
 library/core/src/num/uint_macros.rs | 102 +++++++++++++++++++++++++++-
 library/std/src/io/cursor.rs        |   7 +-
 library/std/src/lib.rs              |   1 +
 5 files changed, 112 insertions(+), 15 deletions(-)

diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 4408b5a3d2088..2e419625d14f6 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -159,6 +159,7 @@
 #![feature(trait_alias)]
 #![feature(transparent_unions)]
 #![feature(try_blocks)]
+#![feature(uint_add_signed)]
 #![feature(unboxed_closures)]
 #![feature(unsized_fn_params)]
 //
diff --git a/library/core/src/num/mod.rs b/library/core/src/num/mod.rs
index 59b68cbe9c0ce..8966a9c11d2b4 100644
--- a/library/core/src/num/mod.rs
+++ b/library/core/src/num/mod.rs
@@ -245,7 +245,7 @@ const ASCII_CASE_MASK: u8 = 0b0010_0000;
 #[lang = "u8"]
 impl u8 {
     widening_impl! { u8, u16, 8 }
-    uint_impl! { u8, u8, 8, 255, 2, "0x82", "0xa", "0x12", "0x12", "0x48", "[0x12]",
+    uint_impl! { u8, u8, i8, 8, 255, 2, "0x82", "0xa", "0x12", "0x12", "0x48", "[0x12]",
     "[0x12]", "", "" }
 
     /// Checks if the value is within the ASCII range.
@@ -779,21 +779,21 @@ impl u8 {
 #[lang = "u16"]
 impl u16 {
     widening_impl! { u16, u32, 16 }
-    uint_impl! { u16, u16, 16, 65535, 4, "0xa003", "0x3a", "0x1234", "0x3412", "0x2c48",
+    uint_impl! { u16, u16, i16, 16, 65535, 4, "0xa003", "0x3a", "0x1234", "0x3412", "0x2c48",
     "[0x34, 0x12]", "[0x12, 0x34]", "", "" }
 }
 
 #[lang = "u32"]
 impl u32 {
     widening_impl! { u32, u64, 32 }
-    uint_impl! { u32, u32, 32, 4294967295, 8, "0x10000b3", "0xb301", "0x12345678",
+    uint_impl! { u32, u32, i32, 32, 4294967295, 8, "0x10000b3", "0xb301", "0x12345678",
     "0x78563412", "0x1e6a2c48", "[0x78, 0x56, 0x34, 0x12]", "[0x12, 0x34, 0x56, 0x78]", "", "" }
 }
 
 #[lang = "u64"]
 impl u64 {
     widening_impl! { u64, u128, 64 }
-    uint_impl! { u64, u64, 64, 18446744073709551615, 12, "0xaa00000000006e1", "0x6e10aa",
+    uint_impl! { u64, u64, i64, 64, 18446744073709551615, 12, "0xaa00000000006e1", "0x6e10aa",
     "0x1234567890123456", "0x5634129078563412", "0x6a2c48091e6a2c48",
     "[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]",
     "[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]",
@@ -802,7 +802,7 @@ impl u64 {
 
 #[lang = "u128"]
 impl u128 {
-    uint_impl! { u128, u128, 128, 340282366920938463463374607431768211455, 16,
+    uint_impl! { u128, u128, i128, 128, 340282366920938463463374607431768211455, 16,
     "0x13f40000000000000000000000004f76", "0x4f7613f4", "0x12345678901234567890123456789012",
     "0x12907856341290785634129078563412", "0x48091e6a2c48091e6a2c48091e6a2c48",
     "[0x12, 0x90, 0x78, 0x56, 0x34, 0x12, 0x90, 0x78, \
@@ -816,7 +816,7 @@ impl u128 {
 #[lang = "usize"]
 impl usize {
     widening_impl! { usize, u32, 16 }
-    uint_impl! { usize, u16, 16, 65535, 4, "0xa003", "0x3a", "0x1234", "0x3412", "0x2c48",
+    uint_impl! { usize, u16, isize, 16, 65535, 4, "0xa003", "0x3a", "0x1234", "0x3412", "0x2c48",
     "[0x34, 0x12]", "[0x12, 0x34]",
     usize_isize_to_xe_bytes_doc!(), usize_isize_from_xe_bytes_doc!() }
 }
@@ -824,7 +824,7 @@ impl usize {
 #[lang = "usize"]
 impl usize {
     widening_impl! { usize, u64, 32 }
-    uint_impl! { usize, u32, 32, 4294967295, 8, "0x10000b3", "0xb301", "0x12345678",
+    uint_impl! { usize, u32, isize, 32, 4294967295, 8, "0x10000b3", "0xb301", "0x12345678",
     "0x78563412", "0x1e6a2c48", "[0x78, 0x56, 0x34, 0x12]", "[0x12, 0x34, 0x56, 0x78]",
     usize_isize_to_xe_bytes_doc!(), usize_isize_from_xe_bytes_doc!() }
 }
@@ -833,7 +833,7 @@ impl usize {
 #[lang = "usize"]
 impl usize {
     widening_impl! { usize, u128, 64 }
-    uint_impl! { usize, u64, 64, 18446744073709551615, 12, "0xaa00000000006e1", "0x6e10aa",
+    uint_impl! { usize, u64, isize, 64, 18446744073709551615, 12, "0xaa00000000006e1", "0x6e10aa",
     "0x1234567890123456", "0x5634129078563412", "0x6a2c48091e6a2c48",
     "[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]",
      "[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]",
diff --git a/library/core/src/num/uint_macros.rs b/library/core/src/num/uint_macros.rs
index 8ce8266263091..67d72a171350b 100644
--- a/library/core/src/num/uint_macros.rs
+++ b/library/core/src/num/uint_macros.rs
@@ -1,5 +1,5 @@
 macro_rules! uint_impl {
-    ($SelfT:ty, $ActualT:ident, $BITS:expr, $MaxV:expr,
+    ($SelfT:ty, $ActualT:ident, $SignedT:ident, $BITS:expr, $MaxV:expr,
         $rot:expr, $rot_op:expr, $rot_result:expr, $swap_op:expr, $swapped:expr,
         $reversed:expr, $le_bytes:expr, $be_bytes:expr,
         $to_xe_bytes_doc:expr, $from_xe_bytes_doc:expr) => {
@@ -442,6 +442,29 @@ macro_rules! uint_impl {
             unsafe { intrinsics::unchecked_add(self, rhs) }
         }
 
+        /// Checked addition with a signed integer. Computes `self + rhs`,
+        /// returning `None` if overflow occurred.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        ///
+        /// ```
+        /// # #![feature(uint_add_signed)]
+        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(2), Some(3));")]
+        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(-2), None);")]
+        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);")]
+        /// ```
+        #[unstable(feature = "uint_add_signed", issue = "none")]
+        #[rustc_const_unstable(feature = "uint_add_signed", issue = "none")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline]
+        pub const fn checked_add_signed(self, rhs: $SignedT) -> Option<Self> {
+            let (a, b) = self.overflowing_add_signed(rhs);
+            if unlikely!(b) {None} else {Some(a)}
+        }
+
         /// Checked integer subtraction. Computes `self - rhs`, returning
         /// `None` if overflow occurred.
         ///
@@ -995,6 +1018,32 @@ macro_rules! uint_impl {
             intrinsics::saturating_add(self, rhs)
         }
 
+        /// Saturating addition with a signed integer. Computes `self + rhs`,
+        /// saturating at the numeric bounds instead of overflowing.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        ///
+        /// ```
+        /// # #![feature(uint_add_signed)]
+        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(2), 3);")]
+        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(-2), 0);")]
+        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).saturating_add_signed(4), ", stringify!($SelfT), "::MAX);")]
+        /// ```
+        #[unstable(feature = "uint_add_signed", issue = "none")]
+        #[rustc_const_unstable(feature = "uint_add_signed", issue = "none")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline]
+        pub const fn saturating_add_signed(self, rhs: $SignedT) -> Self {
+            if rhs >= 0 {
+                self.saturating_add(rhs as Self)
+            } else {
+                self.saturating_sub(rhs.unsigned_abs())
+            }
+        }
+
         /// Saturating integer subtraction. Computes `self - rhs`, saturating
         /// at the numeric bounds instead of overflowing.
         ///
@@ -1111,6 +1160,28 @@ macro_rules! uint_impl {
             intrinsics::wrapping_add(self, rhs)
         }
 
+        /// Wrapping (modular) addition with a signed integer. Computes
+        /// `self + rhs`, wrapping around at the boundary of the type.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        ///
+        /// ```
+        /// # #![feature(uint_add_signed)]
+        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(2), 3);")]
+        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(-2), ", stringify!($SelfT), "::MAX);")]
+        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).wrapping_add_signed(4), 1);")]
+        /// ```
+        #[unstable(feature = "uint_add_signed", issue = "none")]
+        #[rustc_const_unstable(feature = "uint_add_signed", issue = "none")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline]
+        pub const fn wrapping_add_signed(self, rhs: $SignedT) -> Self {
+            self.wrapping_add(rhs as Self)
+        }
+
         /// Wrapping (modular) subtraction. Computes `self - rhs`,
         /// wrapping around at the boundary of the type.
         ///
@@ -1435,6 +1506,35 @@ macro_rules! uint_impl {
             (c, b | d)
         }
 
+        /// Calculates `self` + `rhs` with a signed `rhs`
+        ///
+        /// Returns a tuple of the addition along with a boolean indicating
+        /// whether an arithmetic overflow would occur. If an overflow would
+        /// have occurred then the wrapped value is returned.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        ///
+        /// ```
+        /// # #![feature(uint_add_signed)]
+        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(2), (3, false));")]
+        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(-2), (", stringify!($SelfT), "::MAX, true));")]
+        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_add_signed(4), (1, true));")]
+        /// ```
+        #[unstable(feature = "uint_add_signed", issue = "none")]
+        #[rustc_const_unstable(feature = "uint_add_signed", issue = "none")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline]
+        pub const fn overflowing_add_signed(self, rhs: $SignedT) -> (Self, bool) {
+            if rhs >= 0 {
+                self.overflowing_add(rhs as Self)
+            } else {
+                self.overflowing_sub(rhs.unsigned_abs())
+            }
+        }
+
         /// Calculates `self` - `rhs`
         ///
         /// Returns a tuple of the subtraction along with a boolean indicating
diff --git a/library/std/src/io/cursor.rs b/library/std/src/io/cursor.rs
index 25cc5e67ad14e..980b2531192e8 100644
--- a/library/std/src/io/cursor.rs
+++ b/library/std/src/io/cursor.rs
@@ -292,12 +292,7 @@ where
             SeekFrom::End(n) => (self.inner.as_ref().len() as u64, n),
             SeekFrom::Current(n) => (self.pos, n),
         };
-        let new_pos = if offset >= 0 {
-            base_pos.checked_add(offset as u64)
-        } else {
-            base_pos.checked_sub((offset.wrapping_neg()) as u64)
-        };
-        match new_pos {
+        match base_pos.checked_add_signed(offset) {
             Some(n) => {
                 self.pos = n;
                 Ok(self.pos)
diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index b33a3c5d22fe1..e9a1aa41a63db 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -333,6 +333,7 @@
 #![feature(try_blocks)]
 #![feature(try_reserve)]
 #![feature(try_reserve_kind)]
+#![feature(uint_add_signed)]
 #![feature(unboxed_closures)]
 #![feature(unwrap_infallible)]
 #![feature(vec_into_raw_parts)]

From ab9f8a0b593a832f98188cd755bd467eeb9416d4 Mon Sep 17 00:00:00 2001
From: Alphyr <47725341+a1phyr@users.noreply.github.com>
Date: Fri, 30 Jul 2021 12:11:18 +0200
Subject: [PATCH 04/15] Apply suggestion for `overflowing_add_signed`

Co-authored-by: kennytm <kennytm@gmail.com>
---
 library/core/src/num/uint_macros.rs | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/library/core/src/num/uint_macros.rs b/library/core/src/num/uint_macros.rs
index 67d72a171350b..2c4097a30a1e1 100644
--- a/library/core/src/num/uint_macros.rs
+++ b/library/core/src/num/uint_macros.rs
@@ -1528,11 +1528,8 @@ macro_rules! uint_impl {
                       without modifying the original"]
         #[inline]
         pub const fn overflowing_add_signed(self, rhs: $SignedT) -> (Self, bool) {
-            if rhs >= 0 {
-                self.overflowing_add(rhs as Self)
-            } else {
-                self.overflowing_sub(rhs.unsigned_abs())
-            }
+            let (res, overflowed) = self.overflowing_add(rhs as Self);
+            (res, overflowed ^ (rhs < 0))
         }
 
         /// Calculates `self` - `rhs`

From b5dd5227ee7785174f006a5281622c52533c6075 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20du=20Garreau?= <bdgdlm@outlook.com>
Date: Sat, 7 Aug 2021 11:26:34 +0200
Subject: [PATCH 05/15] Fix doc test

---
 library/core/src/num/uint_macros.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/core/src/num/uint_macros.rs b/library/core/src/num/uint_macros.rs
index 2c4097a30a1e1..e6c675edabcc3 100644
--- a/library/core/src/num/uint_macros.rs
+++ b/library/core/src/num/uint_macros.rs
@@ -453,7 +453,7 @@ macro_rules! uint_impl {
         /// # #![feature(uint_add_signed)]
         #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(2), Some(3));")]
         #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(-2), None);")]
-        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);")]
+        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add_signed(3), None);")]
         /// ```
         #[unstable(feature = "uint_add_signed", issue = "none")]
         #[rustc_const_unstable(feature = "uint_add_signed", issue = "none")]

From 9faf6213558c0f0158eff5f2a911dbd6ab804605 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20du=20Garreau?= <bdgdlm@outlook.com>
Date: Sat, 7 Aug 2021 12:11:59 +0200
Subject: [PATCH 06/15] Add methods to add/sub `uX` to/from `iX`

---
 library/core/src/lib.rs             |   2 +-
 library/core/src/num/int_macros.rs  | 190 ++++++++++++++++++++++++++++
 library/core/src/num/uint_macros.rs |  24 ++--
 library/std/src/lib.rs              |   2 +-
 4 files changed, 204 insertions(+), 14 deletions(-)

diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 2e419625d14f6..f41eeae9cc1fa 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -142,6 +142,7 @@
 #![feature(link_llvm_intrinsics)]
 #![feature(llvm_asm)]
 #![feature(min_specialization)]
+#![feature(mixed_integer_ops)]
 #![cfg_attr(not(bootstrap), feature(must_not_suspend))]
 #![feature(negative_impls)]
 #![feature(never_type)]
@@ -159,7 +160,6 @@
 #![feature(trait_alias)]
 #![feature(transparent_unions)]
 #![feature(try_blocks)]
-#![feature(uint_add_signed)]
 #![feature(unboxed_closures)]
 #![feature(unsized_fn_params)]
 //
diff --git a/library/core/src/num/int_macros.rs b/library/core/src/num/int_macros.rs
index daef5c98967cc..5f299687780ef 100644
--- a/library/core/src/num/int_macros.rs
+++ b/library/core/src/num/int_macros.rs
@@ -433,6 +433,28 @@ macro_rules! int_impl {
             unsafe { intrinsics::unchecked_add(self, rhs) }
         }
 
+        /// Checked addition with an unsigned integer. Computes `self + rhs`,
+        /// returning `None` if overflow occurred.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        ///
+        /// ```
+        /// # #![feature(mixed_integer_ops)]
+        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_unsigned(2), Some(3));")]
+        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add_unsigned(3), None);")]
+        /// ```
+        #[unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[rustc_const_unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline]
+        pub const fn checked_add_unsigned(self, rhs: $UnsignedT) -> Option<Self> {
+            let (a, b) = self.overflowing_add_unsigned(rhs);
+            if unlikely!(b) {None} else {Some(a)}
+        }
+
         /// Checked integer subtraction. Computes `self - rhs`, returning `None` if
         /// overflow occurred.
         ///
@@ -479,6 +501,28 @@ macro_rules! int_impl {
             unsafe { intrinsics::unchecked_sub(self, rhs) }
         }
 
+        /// Checked addition with an unsigned integer. Computes `self + rhs`,
+        /// returning `None` if overflow occurred.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        ///
+        /// ```
+        /// # #![feature(mixed_integer_ops)]
+        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_unsigned(2), Some(-1));")]
+        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).checked_sub_unsigned(3), None);")]
+        /// ```
+        #[unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[rustc_const_unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline]
+        pub const fn checked_sub_unsigned(self, rhs: $UnsignedT) -> Option<Self> {
+            let (a, b) = self.overflowing_sub_unsigned(rhs);
+            if unlikely!(b) {None} else {Some(a)}
+        }
+
         /// Checked integer multiplication. Computes `self * rhs`, returning `None` if
         /// overflow occurred.
         ///
@@ -822,6 +866,31 @@ macro_rules! int_impl {
             intrinsics::saturating_add(self, rhs)
         }
 
+        /// Saturating addition with an unsigned integer. Computes `self + rhs`,
+        /// saturating at the numeric bounds instead of overflowing.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        ///
+        /// ```
+        /// # #![feature(mixed_integer_ops)]
+        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_unsigned(2), 3);")]
+        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add_unsigned(100), ", stringify!($SelfT), "::MAX);")]
+        /// ```
+        #[unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[rustc_const_unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline]
+        pub const fn saturating_add_unsigned(self, rhs: $UnsignedT) -> Self {
+            // Overflow can only happen at the upper bound
+            match self.checked_add_unsigned(rhs) {
+                Some(x) => x,
+                None => Self::MAX,
+            }
+        }
+
         /// Saturating integer subtraction. Computes `self - rhs`, saturating at the
         /// numeric bounds instead of overflowing.
         ///
@@ -843,6 +912,31 @@ macro_rules! int_impl {
             intrinsics::saturating_sub(self, rhs)
         }
 
+        /// Saturating substraction with an unsigned integer. Computes `self - rhs`,
+        /// saturating at the numeric bounds instead of overflowing.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        ///
+        /// ```
+        /// # #![feature(mixed_integer_ops)]
+        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub_unsigned(127), -27);")]
+        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_sub_unsigned(100), ", stringify!($SelfT), "::MIN);")]
+        /// ```
+        #[unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[rustc_const_unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline]
+        pub const fn saturating_sub_unsigned(self, rhs: $UnsignedT) -> Self {
+            // Overflow can only happen at the lower bound
+            match self.checked_sub_unsigned(rhs) {
+                Some(x) => x,
+                None => Self::MIN,
+            }
+        }
+
         /// Saturating integer negation. Computes `-self`, returning `MAX` if `self == MIN`
         /// instead of overflowing.
         ///
@@ -998,6 +1092,27 @@ macro_rules! int_impl {
             intrinsics::wrapping_add(self, rhs)
         }
 
+        /// Wrapping (modular) addition with an unsigned integer. Computes
+        /// `self + rhs`, wrapping around at the boundary of the type.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        ///
+        /// ```
+        /// # #![feature(mixed_integer_ops)]
+        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_add_unsigned(27), 127);")]
+        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_add_unsigned(2), ", stringify!($SelfT), "::MIN + 1);")]
+        /// ```
+        #[unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[rustc_const_unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline(always)]
+        pub const fn wrapping_add_unsigned(self, rhs: $UnsignedT) -> Self {
+            self.wrapping_add(rhs as Self)
+        }
+
         /// Wrapping (modular) subtraction. Computes `self - rhs`, wrapping around at the
         /// boundary of the type.
         ///
@@ -1018,6 +1133,27 @@ macro_rules! int_impl {
             intrinsics::wrapping_sub(self, rhs)
         }
 
+        /// Wrapping (modular) substraction with an unsigned integer. Computes
+        /// `self - rhs`, wrapping around at the boundary of the type.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        ///
+        /// ```
+        /// # #![feature(mixed_integer_ops)]
+        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".wrapping_sub_unsigned(127), -127);")]
+        #[doc = concat!("assert_eq!((-2", stringify!($SelfT), ").wrapping_sub_unsigned(", stringify!($UnsignedT), "::MAX), -1);")]
+        /// ```
+        #[unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[rustc_const_unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline(always)]
+        pub const fn wrapping_sub_unsigned(self, rhs: $UnsignedT) -> Self {
+            self.wrapping_sub(rhs as Self)
+        }
+
         /// Wrapping (modular) multiplication. Computes `self * rhs`, wrapping around at
         /// the boundary of the type.
         ///
@@ -1368,6 +1504,33 @@ macro_rules! int_impl {
             (sum as $SelfT, carry)
         }
 
+        /// Calculates `self` + `rhs` with an unsigned `rhs`
+        ///
+        /// Returns a tuple of the addition along with a boolean indicating
+        /// whether an arithmetic overflow would occur. If an overflow would
+        /// have occurred then the wrapped value is returned.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        ///
+        /// ```
+        /// # #![feature(mixed_integer_ops)]
+        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_unsigned(2), (3, false));")]
+        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN).overflowing_add_unsigned(", stringify!($UnsignedT), "::MAX), (", stringify!($SelfT), "::MAX, false));")]
+        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_add_unsigned(3), (", stringify!($SelfT), "::MIN, true));")]
+        /// ```
+        #[unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[rustc_const_unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline]
+        pub const fn overflowing_add_unsigned(self, rhs: $UnsignedT) -> (Self, bool) {
+            let rhs = rhs as Self;
+            let (res, overflowed) = self.overflowing_add(rhs);
+            (res, overflowed ^ (rhs < 0))
+        }
+
         /// Calculates `self` - `rhs`
         ///
         /// Returns a tuple of the subtraction along with a boolean indicating whether an arithmetic overflow
@@ -1419,6 +1582,33 @@ macro_rules! int_impl {
             (sum as $SelfT, borrow)
         }
 
+        /// Calculates `self` - `rhs` with an unsigned `rhs`
+        ///
+        /// Returns a tuple of the substraction along with a boolean indicating
+        /// whether an arithmetic overflow would occur. If an overflow would
+        /// have occurred then the wrapped value is returned.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        ///
+        /// ```
+        /// # #![feature(mixed_integer_ops)]
+        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_unsigned(2), (-1, false));")]
+        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX).overflowing_sub_unsigned(", stringify!($UnsignedT), "::MAX), (", stringify!($SelfT), "::MIN, false));")]
+        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).overflowing_sub_unsigned(3), (", stringify!($SelfT), "::MAX, true));")]
+        /// ```
+        #[unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[rustc_const_unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline]
+        pub const fn overflowing_sub_unsigned(self, rhs: $UnsignedT) -> (Self, bool) {
+            let rhs = rhs as Self;
+            let (res, overflowed) = self.overflowing_sub(rhs);
+            (res, overflowed ^ (rhs < 0))
+        }
+
         /// Calculates the multiplication of `self` and `rhs`.
         ///
         /// Returns a tuple of the multiplication along with a boolean indicating whether an arithmetic overflow
diff --git a/library/core/src/num/uint_macros.rs b/library/core/src/num/uint_macros.rs
index e6c675edabcc3..5a65f77a87993 100644
--- a/library/core/src/num/uint_macros.rs
+++ b/library/core/src/num/uint_macros.rs
@@ -450,13 +450,13 @@ macro_rules! uint_impl {
         /// Basic usage:
         ///
         /// ```
-        /// # #![feature(uint_add_signed)]
+        /// # #![feature(mixed_integer_ops)]
         #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(2), Some(3));")]
         #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(-2), None);")]
         #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add_signed(3), None);")]
         /// ```
-        #[unstable(feature = "uint_add_signed", issue = "none")]
-        #[rustc_const_unstable(feature = "uint_add_signed", issue = "none")]
+        #[unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[rustc_const_unstable(feature = "mixed_integer_ops", issue = "87840")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -1026,13 +1026,13 @@ macro_rules! uint_impl {
         /// Basic usage:
         ///
         /// ```
-        /// # #![feature(uint_add_signed)]
+        /// # #![feature(mixed_integer_ops)]
         #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(2), 3);")]
         #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(-2), 0);")]
         #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).saturating_add_signed(4), ", stringify!($SelfT), "::MAX);")]
         /// ```
-        #[unstable(feature = "uint_add_signed", issue = "none")]
-        #[rustc_const_unstable(feature = "uint_add_signed", issue = "none")]
+        #[unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[rustc_const_unstable(feature = "mixed_integer_ops", issue = "87840")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -1168,13 +1168,13 @@ macro_rules! uint_impl {
         /// Basic usage:
         ///
         /// ```
-        /// # #![feature(uint_add_signed)]
+        /// # #![feature(mixed_integer_ops)]
         #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(2), 3);")]
         #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(-2), ", stringify!($SelfT), "::MAX);")]
         #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).wrapping_add_signed(4), 1);")]
         /// ```
-        #[unstable(feature = "uint_add_signed", issue = "none")]
-        #[rustc_const_unstable(feature = "uint_add_signed", issue = "none")]
+        #[unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[rustc_const_unstable(feature = "mixed_integer_ops", issue = "87840")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -1517,13 +1517,13 @@ macro_rules! uint_impl {
         /// Basic usage:
         ///
         /// ```
-        /// # #![feature(uint_add_signed)]
+        /// # #![feature(mixed_integer_ops)]
         #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(2), (3, false));")]
         #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(-2), (", stringify!($SelfT), "::MAX, true));")]
         #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_add_signed(4), (1, true));")]
         /// ```
-        #[unstable(feature = "uint_add_signed", issue = "none")]
-        #[rustc_const_unstable(feature = "uint_add_signed", issue = "none")]
+        #[unstable(feature = "mixed_integer_ops", issue = "87840")]
+        #[rustc_const_unstable(feature = "mixed_integer_ops", issue = "87840")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index e9a1aa41a63db..1781a3cb7c402 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -297,6 +297,7 @@
 #![feature(maybe_uninit_slice)]
 #![feature(maybe_uninit_uninit_array)]
 #![feature(min_specialization)]
+#![feature(mixed_integer_ops)]
 #![cfg_attr(not(bootstrap), feature(must_not_suspend))]
 #![feature(needs_panic_runtime)]
 #![feature(negative_impls)]
@@ -333,7 +334,6 @@
 #![feature(try_blocks)]
 #![feature(try_reserve)]
 #![feature(try_reserve_kind)]
-#![feature(uint_add_signed)]
 #![feature(unboxed_closures)]
 #![feature(unwrap_infallible)]
 #![feature(vec_into_raw_parts)]

From 70e55a8938bb84542f73a127edd5c91f2c8bd0aa Mon Sep 17 00:00:00 2001
From: Alphyr <47725341+a1phyr@users.noreply.github.com>
Date: Sun, 3 Oct 2021 22:44:07 +0200
Subject: [PATCH 07/15] Apply suggestions

Co-authored-by: kennytm <kennytm@gmail.com>
---
 library/core/src/num/int_macros.rs | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/library/core/src/num/int_macros.rs b/library/core/src/num/int_macros.rs
index 5f299687780ef..540b7d36625af 100644
--- a/library/core/src/num/int_macros.rs
+++ b/library/core/src/num/int_macros.rs
@@ -501,7 +501,7 @@ macro_rules! int_impl {
             unsafe { intrinsics::unchecked_sub(self, rhs) }
         }
 
-        /// Checked addition with an unsigned integer. Computes `self + rhs`,
+        /// Checked subtraction with an unsigned integer. Computes `self - rhs`,
         /// returning `None` if overflow occurred.
         ///
         /// # Examples
@@ -885,10 +885,7 @@ macro_rules! int_impl {
         #[inline]
         pub const fn saturating_add_unsigned(self, rhs: $UnsignedT) -> Self {
             // Overflow can only happen at the upper bound
-            match self.checked_add_unsigned(rhs) {
-                Some(x) => x,
-                None => Self::MAX,
-            }
+            self.checked_add_unsigned(rhs).unwrap_or(Self::MAX)
         }
 
         /// Saturating integer subtraction. Computes `self - rhs`, saturating at the
@@ -912,7 +909,7 @@ macro_rules! int_impl {
             intrinsics::saturating_sub(self, rhs)
         }
 
-        /// Saturating substraction with an unsigned integer. Computes `self - rhs`,
+        /// Saturating subtraction with an unsigned integer. Computes `self - rhs`,
         /// saturating at the numeric bounds instead of overflowing.
         ///
         /// # Examples
@@ -931,10 +928,7 @@ macro_rules! int_impl {
         #[inline]
         pub const fn saturating_sub_unsigned(self, rhs: $UnsignedT) -> Self {
             // Overflow can only happen at the lower bound
-            match self.checked_sub_unsigned(rhs) {
-                Some(x) => x,
-                None => Self::MIN,
-            }
+            self.checked_sub_unsigned(rhs).unwrap_or(Self::MIN)
         }
 
         /// Saturating integer negation. Computes `-self`, returning `MAX` if `self == MIN`
@@ -1133,7 +1127,7 @@ macro_rules! int_impl {
             intrinsics::wrapping_sub(self, rhs)
         }
 
-        /// Wrapping (modular) substraction with an unsigned integer. Computes
+        /// Wrapping (modular) subtraction with an unsigned integer. Computes
         /// `self - rhs`, wrapping around at the boundary of the type.
         ///
         /// # Examples
@@ -1584,7 +1578,7 @@ macro_rules! int_impl {
 
         /// Calculates `self` - `rhs` with an unsigned `rhs`
         ///
-        /// Returns a tuple of the substraction along with a boolean indicating
+        /// Returns a tuple of the subtraction along with a boolean indicating
         /// whether an arithmetic overflow would occur. If an overflow would
         /// have occurred then the wrapped value is returned.
         ///

From 4846fd92c0cc82545c5fd33c9ab3007f03f0f9f7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20du=20Garreau?= <bdgdlm@outlook.com>
Date: Sun, 3 Oct 2021 22:56:34 +0200
Subject: [PATCH 08/15] Revert suggested use of `unwrap_or`

---
 library/core/src/num/int_macros.rs | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/library/core/src/num/int_macros.rs b/library/core/src/num/int_macros.rs
index 540b7d36625af..5bdb6ed91761f 100644
--- a/library/core/src/num/int_macros.rs
+++ b/library/core/src/num/int_macros.rs
@@ -885,7 +885,11 @@ macro_rules! int_impl {
         #[inline]
         pub const fn saturating_add_unsigned(self, rhs: $UnsignedT) -> Self {
             // Overflow can only happen at the upper bound
-            self.checked_add_unsigned(rhs).unwrap_or(Self::MAX)
+            // We cannot use `unwrap_or` here because it is not `const`
+            match self.checked_add_unsigned(rhs) {
+                Some(x) => x,
+                None => Self::MAX,
+            }
         }
 
         /// Saturating integer subtraction. Computes `self - rhs`, saturating at the
@@ -928,7 +932,11 @@ macro_rules! int_impl {
         #[inline]
         pub const fn saturating_sub_unsigned(self, rhs: $UnsignedT) -> Self {
             // Overflow can only happen at the lower bound
-            self.checked_sub_unsigned(rhs).unwrap_or(Self::MIN)
+            // We cannot use `unwrap_or` here because it is not `const`
+            match self.checked_sub_unsigned(rhs) {
+                Some(x) => x,
+                None => Self::MIN,
+            }
         }
 
         /// Saturating integer negation. Computes `-self`, returning `MAX` if `self == MIN`

From 47edde1086412b36e9efd6098b191ec15a2a760a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20du=20Garreau?= <bdgdlm@outlook.com>
Date: Mon, 4 Oct 2021 18:52:17 +0200
Subject: [PATCH 09/15] Optimize `saturating_add_signed`

---
 library/core/src/num/uint_macros.rs | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/library/core/src/num/uint_macros.rs b/library/core/src/num/uint_macros.rs
index 5a65f77a87993..96375b82582ed 100644
--- a/library/core/src/num/uint_macros.rs
+++ b/library/core/src/num/uint_macros.rs
@@ -1037,10 +1037,13 @@ macro_rules! uint_impl {
                       without modifying the original"]
         #[inline]
         pub const fn saturating_add_signed(self, rhs: $SignedT) -> Self {
-            if rhs >= 0 {
-                self.saturating_add(rhs as Self)
+            let (res, overflow) = self.overflowing_add(rhs as Self);
+            if overflow == (rhs < 0) {
+                res
+            } else if overflow {
+                Self::MAX
             } else {
-                self.saturating_sub(rhs.unsigned_abs())
+                0
             }
         }
 

From 388bcc1cb086c567f17a4933bfb1d3f14eb19fb7 Mon Sep 17 00:00:00 2001
From: Fabian Wolff <fabian.wolff@alumni.ethz.ch>
Date: Mon, 4 Oct 2021 21:15:02 +0200
Subject: [PATCH 10/15] Fix suggestion to borrow when casting from pointer to
 reference

---
 compiler/rustc_typeck/src/check/cast.rs       | 44 +++++++++++++++----
 src/test/ui/cast/issue-89497.fixed            | 10 +++++
 src/test/ui/cast/issue-89497.rs               | 10 +++++
 src/test/ui/cast/issue-89497.stderr           | 15 +++++++
 src/test/ui/error-codes/E0605.stderr          |  5 ++-
 src/test/ui/issues/issue-2995.stderr          |  5 ++-
 .../ui/mismatched_types/cast-rfc0401.stderr   |  5 ++-
 7 files changed, 80 insertions(+), 14 deletions(-)
 create mode 100644 src/test/ui/cast/issue-89497.fixed
 create mode 100644 src/test/ui/cast/issue-89497.rs
 create mode 100644 src/test/ui/cast/issue-89497.stderr

diff --git a/compiler/rustc_typeck/src/check/cast.rs b/compiler/rustc_typeck/src/check/cast.rs
index 4ea7a8694c075..fe0de61ab89e2 100644
--- a/compiler/rustc_typeck/src/check/cast.rs
+++ b/compiler/rustc_typeck/src/check/cast.rs
@@ -351,7 +351,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                 );
                 let mut sugg = None;
                 let mut sugg_mutref = false;
-                if let ty::Ref(reg, _, mutbl) = *self.cast_ty.kind() {
+                if let ty::Ref(reg, cast_ty, mutbl) = *self.cast_ty.kind() {
                     if let ty::RawPtr(TypeAndMut { ty: expr_ty, .. }) = *self.expr_ty.kind() {
                         if fcx
                             .try_coerce(
@@ -366,7 +366,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                             )
                             .is_ok()
                         {
-                            sugg = Some(format!("&{}*", mutbl.prefix_str()));
+                            sugg = Some((format!("&{}*", mutbl.prefix_str()), cast_ty == expr_ty));
                         }
                     } else if let ty::Ref(expr_reg, expr_ty, expr_mutbl) = *self.expr_ty.kind() {
                         if expr_mutbl == Mutability::Not
@@ -400,7 +400,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                             )
                             .is_ok()
                     {
-                        sugg = Some(format!("&{}", mutbl.prefix_str()));
+                        sugg = Some((format!("&{}", mutbl.prefix_str()), false));
                     }
                 } else if let ty::RawPtr(TypeAndMut { mutbl, .. }) = *self.cast_ty.kind() {
                     if fcx
@@ -416,19 +416,47 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                         )
                         .is_ok()
                     {
-                        sugg = Some(format!("&{}", mutbl.prefix_str()));
+                        sugg = Some((format!("&{}", mutbl.prefix_str()), false));
                     }
                 }
                 if sugg_mutref {
                     err.span_label(self.span, "invalid cast");
                     err.span_note(self.expr.span, "this reference is immutable");
                     err.span_note(self.cast_span, "trying to cast to a mutable reference type");
-                } else if let Some(sugg) = sugg {
+                } else if let Some((sugg, remove_cast)) = sugg {
                     err.span_label(self.span, "invalid cast");
-                    err.span_suggestion_verbose(
-                        self.expr.span.shrink_to_lo(),
+
+                    let has_parens = fcx
+                        .tcx
+                        .sess
+                        .source_map()
+                        .span_to_snippet(self.expr.span)
+                        .map_or(false, |snip| snip.starts_with("("));
+
+                    // Very crude check to see whether the expression must be wrapped
+                    // in parentheses for the suggestion to work (issue #89497).
+                    // Can/should be extended in the future.
+                    let needs_parens = !has_parens
+                        && match self.expr.kind {
+                            hir::ExprKind::Cast(..) => true,
+                            _ => false,
+                        };
+
+                    let mut suggestion = vec![(self.expr.span.shrink_to_lo(), sugg)];
+                    if needs_parens {
+                        suggestion[0].1 += "(";
+                        suggestion.push((self.expr.span.shrink_to_hi(), ")".to_string()));
+                    }
+                    if remove_cast {
+                        suggestion.push((
+                            self.expr.span.shrink_to_hi().to(self.cast_span),
+                            String::new(),
+                        ));
+                    }
+
+                    err.multipart_suggestion_verbose(
                         "consider borrowing the value",
-                        sugg,
+                        suggestion,
                         Applicability::MachineApplicable,
                     );
                 } else if !matches!(
diff --git a/src/test/ui/cast/issue-89497.fixed b/src/test/ui/cast/issue-89497.fixed
new file mode 100644
index 0000000000000..04c10a5f79ed4
--- /dev/null
+++ b/src/test/ui/cast/issue-89497.fixed
@@ -0,0 +1,10 @@
+// Regression test for issue #89497.
+
+// run-rustfix
+
+fn main() {
+    let pointer: usize = &1_i32 as *const i32 as usize;
+    let _reference: &'static i32 = unsafe { &*(pointer as *const i32) };
+    //~^ ERROR: non-primitive cast
+    //~| HELP: consider borrowing the value
+}
diff --git a/src/test/ui/cast/issue-89497.rs b/src/test/ui/cast/issue-89497.rs
new file mode 100644
index 0000000000000..76301b704c81c
--- /dev/null
+++ b/src/test/ui/cast/issue-89497.rs
@@ -0,0 +1,10 @@
+// Regression test for issue #89497.
+
+// run-rustfix
+
+fn main() {
+    let pointer: usize = &1_i32 as *const i32 as usize;
+    let _reference: &'static i32 = unsafe { pointer as *const i32 as &'static i32 };
+    //~^ ERROR: non-primitive cast
+    //~| HELP: consider borrowing the value
+}
diff --git a/src/test/ui/cast/issue-89497.stderr b/src/test/ui/cast/issue-89497.stderr
new file mode 100644
index 0000000000000..3726f8a41015e
--- /dev/null
+++ b/src/test/ui/cast/issue-89497.stderr
@@ -0,0 +1,15 @@
+error[E0605]: non-primitive cast: `*const i32` as `&'static i32`
+  --> $DIR/issue-89497.rs:7:45
+   |
+LL |     let _reference: &'static i32 = unsafe { pointer as *const i32 as &'static i32 };
+   |                                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ invalid cast
+   |
+help: consider borrowing the value
+   |
+LL -     let _reference: &'static i32 = unsafe { pointer as *const i32 as &'static i32 };
+LL +     let _reference: &'static i32 = unsafe { &*(pointer as *const i32) };
+   | 
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0605`.
diff --git a/src/test/ui/error-codes/E0605.stderr b/src/test/ui/error-codes/E0605.stderr
index e5647ee6d0968..d082b6c10cc2a 100644
--- a/src/test/ui/error-codes/E0605.stderr
+++ b/src/test/ui/error-codes/E0605.stderr
@@ -12,8 +12,9 @@ LL |     v as &u8;
    |
 help: consider borrowing the value
    |
-LL |     &*v as &u8;
-   |     ++
+LL -     v as &u8;
+LL +     &*v;
+   | 
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/issues/issue-2995.stderr b/src/test/ui/issues/issue-2995.stderr
index 455d32e233ab9..7616f987d7312 100644
--- a/src/test/ui/issues/issue-2995.stderr
+++ b/src/test/ui/issues/issue-2995.stderr
@@ -6,8 +6,9 @@ LL |     let _q: &isize = p as &isize;
    |
 help: consider borrowing the value
    |
-LL |     let _q: &isize = &*p as &isize;
-   |                      ++
+LL -     let _q: &isize = p as &isize;
+LL +     let _q: &isize = &*p;
+   | 
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/mismatched_types/cast-rfc0401.stderr b/src/test/ui/mismatched_types/cast-rfc0401.stderr
index a47eb87cff06c..7f91d5ed42ce4 100644
--- a/src/test/ui/mismatched_types/cast-rfc0401.stderr
+++ b/src/test/ui/mismatched_types/cast-rfc0401.stderr
@@ -28,8 +28,9 @@ LL |     let _ = v as &u8;
    |
 help: consider borrowing the value
    |
-LL |     let _ = &*v as &u8;
-   |             ++
+LL -     let _ = v as &u8;
+LL +     let _ = &*v;
+   | 
 
 error[E0605]: non-primitive cast: `*const u8` as `E`
   --> $DIR/cast-rfc0401.rs:30:13

From c79447e708541abda1e5075385c9ef8810ebc715 Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen@gmail.com>
Date: Mon, 4 Oct 2021 22:11:53 +0100
Subject: [PATCH 11/15] library std, libc dependency update

to solve #87528 build.
---
 Cargo.lock             | 4 ++--
 library/std/Cargo.toml | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index a4e1ab6c1e4a8..b596e09828afa 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1892,9 +1892,9 @@ checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"
 
 [[package]]
 name = "libc"
-version = "0.2.99"
+version = "0.2.103"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a7f823d141fe0a24df1e23b4af4e3c7ba9e5966ec514ea068c93024aa7deb765"
+checksum = "dd8f7255a17a627354f321ef0055d63b898c6fb27eff628af4d1b66b7331edf6"
 dependencies = [
  "rustc-std-workspace-core",
 ]
diff --git a/library/std/Cargo.toml b/library/std/Cargo.toml
index 2b77dc54ab35c..6bc445c6f2b07 100644
--- a/library/std/Cargo.toml
+++ b/library/std/Cargo.toml
@@ -15,7 +15,7 @@ cfg-if = { version = "0.1.8", features = ['rustc-dep-of-std'] }
 panic_unwind = { path = "../panic_unwind", optional = true }
 panic_abort = { path = "../panic_abort" }
 core = { path = "../core" }
-libc = { version = "0.2.99", default-features = false, features = ['rustc-dep-of-std'] }
+libc = { version = "0.2.103", default-features = false, features = ['rustc-dep-of-std'] }
 compiler_builtins = { version = "0.1.44" }
 profiler_builtins = { path = "../profiler_builtins", optional = true }
 unwind = { path = "../unwind" }

From b2e4e59fbe201ff23fd2911f2650827ad46902b9 Mon Sep 17 00:00:00 2001
From: DeveloperC286 <DeveloperC@protonmail.com>
Date: Fri, 17 Sep 2021 18:25:21 +0100
Subject: [PATCH 12/15] refactor: VecDeques Drain fields to private

---
 .../alloc/src/collections/vec_deque/drain.rs  | 19 +++++++++++----
 .../alloc/src/collections/vec_deque/mod.rs    | 24 +++++++++----------
 2 files changed, 26 insertions(+), 17 deletions(-)

diff --git a/library/alloc/src/collections/vec_deque/drain.rs b/library/alloc/src/collections/vec_deque/drain.rs
index dfa0227dea3b8..05f94da6de70d 100644
--- a/library/alloc/src/collections/vec_deque/drain.rs
+++ b/library/alloc/src/collections/vec_deque/drain.rs
@@ -18,10 +18,21 @@ pub struct Drain<
     T: 'a,
     #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
 > {
-    pub(crate) after_tail: usize,
-    pub(crate) after_head: usize,
-    pub(crate) iter: Iter<'a, T>,
-    pub(crate) deque: NonNull<VecDeque<T, A>>,
+    after_tail: usize,
+    after_head: usize,
+    iter: Iter<'a, T>,
+    deque: NonNull<VecDeque<T, A>>,
+}
+
+impl<'a, T, A: Allocator> Drain<'a, T, A> {
+    pub(super) unsafe fn new(
+        after_tail: usize,
+        after_head: usize,
+        iter: Iter<'a, T>,
+        deque: NonNull<VecDeque<T, A>>,
+    ) -> Self {
+        Drain { after_tail, after_head, iter, deque }
+    }
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
diff --git a/library/alloc/src/collections/vec_deque/mod.rs b/library/alloc/src/collections/vec_deque/mod.rs
index f4de2b2ebe5dc..ea3136cae42b5 100644
--- a/library/alloc/src/collections/vec_deque/mod.rs
+++ b/library/alloc/src/collections/vec_deque/mod.rs
@@ -1269,19 +1269,17 @@ impl<T, A: Allocator> VecDeque<T, A> {
         // the drain is complete and the Drain destructor is run.
         self.head = drain_tail;
 
-        Drain {
-            deque: NonNull::from(&mut *self),
-            after_tail: drain_head,
-            after_head: head,
-            iter: Iter {
-                tail: drain_tail,
-                head: drain_head,
-                // Crucially, we only create shared references from `self` here and read from
-                // it.  We do not write to `self` nor reborrow to a mutable reference.
-                // Hence the raw pointer we created above, for `deque`, remains valid.
-                ring: unsafe { self.buffer_as_slice() },
-            },
-        }
+        let deque = NonNull::from(&mut *self);
+        let iter = Iter {
+            tail: drain_tail,
+            head: drain_head,
+            // Crucially, we only create shared references from `self` here and read from
+            // it.  We do not write to `self` nor reborrow to a mutable reference.
+            // Hence the raw pointer we created above, for `deque`, remains valid.
+            ring: unsafe { self.buffer_as_slice() },
+        };
+
+        unsafe { Drain::new(drain_head, head, iter, deque) }
     }
 
     /// Clears the `VecDeque`, removing all values.

From 5af61cb114e4af46e5c1c6c97b4556d5f007536f Mon Sep 17 00:00:00 2001
From: DeveloperC <DeveloperC@protonmail.com>
Date: Sat, 25 Sep 2021 13:55:45 +0100
Subject: [PATCH 13/15] refactor: VecDeques IterMut fields to private

Made the fields of VecDeque's IterMut private by creating a IterMut::new(...) function to create a new instance of IterMut and migrating usage to use IterMut::new(...).
---
 .../src/collections/vec_deque/iter_mut.rs     | 19 +++++++++++++++----
 .../alloc/src/collections/vec_deque/mod.rs    | 18 ++++++------------
 2 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/library/alloc/src/collections/vec_deque/iter_mut.rs b/library/alloc/src/collections/vec_deque/iter_mut.rs
index 7700b31cf5b46..31e6e3b06af5f 100644
--- a/library/alloc/src/collections/vec_deque/iter_mut.rs
+++ b/library/alloc/src/collections/vec_deque/iter_mut.rs
@@ -13,10 +13,21 @@ use super::{count, wrap_index, RingSlices};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct IterMut<'a, T: 'a> {
     // Internal safety invariant: the entire slice is dereferencable.
-    pub(crate) ring: *mut [T],
-    pub(crate) tail: usize,
-    pub(crate) head: usize,
-    pub(crate) phantom: PhantomData<&'a mut [T]>,
+    ring: *mut [T],
+    tail: usize,
+    head: usize,
+    phantom: PhantomData<&'a mut [T]>,
+}
+
+impl<'a, T> IterMut<'a, T> {
+    pub(super) unsafe fn new(
+        ring: *mut [T],
+        tail: usize,
+        head: usize,
+        phantom: PhantomData<&'a mut [T]>,
+    ) -> Self {
+        IterMut { ring, tail, head, phantom }
+    }
 }
 
 // SAFETY: we do nothing thread-local and there is no interior mutability,
diff --git a/library/alloc/src/collections/vec_deque/mod.rs b/library/alloc/src/collections/vec_deque/mod.rs
index f4de2b2ebe5dc..54fcb358ede1b 100644
--- a/library/alloc/src/collections/vec_deque/mod.rs
+++ b/library/alloc/src/collections/vec_deque/mod.rs
@@ -1000,12 +1000,9 @@ impl<T, A: Allocator> VecDeque<T, A> {
     pub fn iter_mut(&mut self) -> IterMut<'_, T> {
         // SAFETY: The internal `IterMut` safety invariant is established because the
         // `ring` we create is a dereferencable slice for lifetime '_.
-        IterMut {
-            tail: self.tail,
-            head: self.head,
-            ring: ptr::slice_from_raw_parts_mut(self.ptr(), self.cap()),
-            phantom: PhantomData,
-        }
+        let ring = ptr::slice_from_raw_parts_mut(self.ptr(), self.cap());
+
+        unsafe { IterMut::new(ring, self.tail, self.head, PhantomData) }
     }
 
     /// Returns a pair of slices which contain, in order, the contents of the
@@ -1192,12 +1189,9 @@ impl<T, A: Allocator> VecDeque<T, A> {
 
         // SAFETY: The internal `IterMut` safety invariant is established because the
         // `ring` we create is a dereferencable slice for lifetime '_.
-        IterMut {
-            tail,
-            head,
-            ring: ptr::slice_from_raw_parts_mut(self.ptr(), self.cap()),
-            phantom: PhantomData,
-        }
+        let ring = ptr::slice_from_raw_parts_mut(self.ptr(), self.cap());
+
+        unsafe { IterMut::new(ring, tail, head, PhantomData) }
     }
 
     /// Creates a draining iterator that removes the specified range in the

From 3c974adb4c4c6de497a36dec362af6c0928c7367 Mon Sep 17 00:00:00 2001
From: Aaron Hill <aa1ronham@gmail.com>
Date: Sun, 3 Oct 2021 15:25:26 -0500
Subject: [PATCH 14/15] Note specific regions involved in 'borrowed data
 escapes' error

Fixes #67007

Currently, a 'borrowed data escapes' error does not mention
the specific lifetime involved (except indirectly through a suggestion
about adding a lifetime bound). We now explain the specific lifetime
relationship that failed to hold, which improves otherwise vague
error messages.
---
 .../src/diagnostics/region_errors.rs          | 21 +++++++++++
 .../async-await/issues/issue-62097.nll.stderr | 10 ++++--
 .../dyn-trait.nll.stderr                      |  9 +++--
 src/test/ui/issues/issue-16683.nll.stderr     | 13 +++++--
 src/test/ui/issues/issue-17758.nll.stderr     | 13 +++++--
 ...etime-bound-will-change-warning.nll.stderr | 18 +++++++---
 ...oximated-shorter-to-static-no-bound.stderr |  9 +++--
 ...mated-shorter-to-static-wrong-bound.stderr |  9 +++--
 src/test/ui/nll/issue-67007-escaping-data.rs  | 26 ++++++++++++++
 .../ui/nll/issue-67007-escaping-data.stderr   | 21 +++++++++++
 .../ui/nll/outlives-suggestion-simple.stderr  |  9 ++++-
 .../user-annotations/closure-substs.stderr    |  9 +++--
 .../object-lifetime-default-mybox.nll.stderr  |  9 +++--
 src/test/ui/regions/issue-78262.nll.stderr    |  7 ++--
 .../ui/regions/issue-78262.polonius.stderr    |  7 ++--
 ...nvariant-static-error-reporting.nll.stderr |  9 +++--
 ...hod-type-parameters-trait-bound.nll.stderr | 13 ++++---
 ...rait-with-implicit-static-bound.nll.stderr | 36 ++++++++++++++-----
 18 files changed, 209 insertions(+), 39 deletions(-)
 create mode 100644 src/test/ui/nll/issue-67007-escaping-data.rs
 create mode 100644 src/test/ui/nll/issue-67007-escaping-data.stderr

diff --git a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
index d05cfebc5f02e..11cdbe84accb7 100644
--- a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
@@ -498,6 +498,27 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             diag.span_label(*span, format!("`{}` escapes the {} body here", fr_name, escapes_from));
         }
 
+        // Only show an extra note if we can find an 'error region' for both of the region
+        // variables. This avoids showing a noisy note that just mentions 'synthetic' regions
+        // that don't help the user understand the error.
+        if self.to_error_region(errci.fr).is_some()
+            && self.to_error_region(errci.outlived_fr).is_some()
+        {
+            let fr_region_name = self.give_region_a_name(errci.fr).unwrap();
+            fr_region_name.highlight_region_name(&mut diag);
+            let outlived_fr_region_name = self.give_region_a_name(errci.outlived_fr).unwrap();
+            outlived_fr_region_name.highlight_region_name(&mut diag);
+
+            diag.span_label(
+                *span,
+                format!(
+                    "{}requires that `{}` must outlive `{}`",
+                    category.description(),
+                    fr_region_name,
+                    outlived_fr_region_name,
+                ),
+            );
+        }
         diag
     }
 
diff --git a/src/test/ui/async-await/issues/issue-62097.nll.stderr b/src/test/ui/async-await/issues/issue-62097.nll.stderr
index e71bcf5822808..786f621326049 100644
--- a/src/test/ui/async-await/issues/issue-62097.nll.stderr
+++ b/src/test/ui/async-await/issues/issue-62097.nll.stderr
@@ -20,9 +20,15 @@ error[E0521]: borrowed data escapes outside of associated function
   --> $DIR/issue-62097.rs:13:9
    |
 LL |     pub async fn run_dummy_fn(&self) {
-   |                               ----- `self` is a reference that is only valid in the associated function body
+   |                               -----
+   |                               |
+   |                               `self` is a reference that is only valid in the associated function body
+   |                               let's call the lifetime of this reference `'1`
 LL |         foo(|| self.bar()).await;
-   |         ^^^^^^^^^^^^^^^^^^ `self` escapes the associated function body here
+   |         ^^^^^^^^^^^^^^^^^^
+   |         |
+   |         `self` escapes the associated function body here
+   |         argument requires that `'1` must outlive `'static`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/impl-header-lifetime-elision/dyn-trait.nll.stderr b/src/test/ui/impl-header-lifetime-elision/dyn-trait.nll.stderr
index e49bd9da754d6..88c260b18cbb0 100644
--- a/src/test/ui/impl-header-lifetime-elision/dyn-trait.nll.stderr
+++ b/src/test/ui/impl-header-lifetime-elision/dyn-trait.nll.stderr
@@ -2,9 +2,14 @@ error[E0521]: borrowed data escapes outside of function
   --> $DIR/dyn-trait.rs:20:5
    |
 LL | fn with_dyn_debug_static<'a>(x: Box<dyn Debug + 'a>) {
-   |                              - `x` is a reference that is only valid in the function body
+   |                          --  - `x` is a reference that is only valid in the function body
+   |                          |
+   |                          lifetime `'a` defined here
 LL |     static_val(x);
-   |     ^^^^^^^^^^^^^ `x` escapes the function body here
+   |     ^^^^^^^^^^^^^
+   |     |
+   |     `x` escapes the function body here
+   |     argument requires that `'a` must outlive `'static`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-16683.nll.stderr b/src/test/ui/issues/issue-16683.nll.stderr
index 51d86eaf9e60c..0e8f520353fba 100644
--- a/src/test/ui/issues/issue-16683.nll.stderr
+++ b/src/test/ui/issues/issue-16683.nll.stderr
@@ -1,10 +1,19 @@
 error[E0521]: borrowed data escapes outside of associated function
   --> $DIR/issue-16683.rs:4:9
    |
+LL | trait T<'a> {
+   |         -- lifetime `'a` defined here
+LL |     fn a(&'a self) -> &'a bool;
 LL |     fn b(&self) {
-   |          ----- `self` is a reference that is only valid in the associated function body
+   |          -----
+   |          |
+   |          `self` is a reference that is only valid in the associated function body
+   |          let's call the lifetime of this reference `'1`
 LL |         self.a();
-   |         ^^^^^^^^ `self` escapes the associated function body here
+   |         ^^^^^^^^
+   |         |
+   |         `self` escapes the associated function body here
+   |         argument requires that `'1` must outlive `'a`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-17758.nll.stderr b/src/test/ui/issues/issue-17758.nll.stderr
index 075c141ed7af6..b929fdbf3687a 100644
--- a/src/test/ui/issues/issue-17758.nll.stderr
+++ b/src/test/ui/issues/issue-17758.nll.stderr
@@ -1,10 +1,19 @@
 error[E0521]: borrowed data escapes outside of associated function
   --> $DIR/issue-17758.rs:7:9
    |
+LL | trait Foo<'a> {
+   |           -- lifetime `'a` defined here
+LL |     fn foo(&'a self);
 LL |     fn bar(&self) {
-   |            ----- `self` is a reference that is only valid in the associated function body
+   |            -----
+   |            |
+   |            `self` is a reference that is only valid in the associated function body
+   |            let's call the lifetime of this reference `'1`
 LL |         self.foo();
-   |         ^^^^^^^^^^ `self` escapes the associated function body here
+   |         ^^^^^^^^^^
+   |         |
+   |         `self` escapes the associated function body here
+   |         argument requires that `'1` must outlive `'a`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/lifetimes/lifetime-bound-will-change-warning.nll.stderr b/src/test/ui/lifetimes/lifetime-bound-will-change-warning.nll.stderr
index 050d5fcf05ef4..6f3f84096e400 100644
--- a/src/test/ui/lifetimes/lifetime-bound-will-change-warning.nll.stderr
+++ b/src/test/ui/lifetimes/lifetime-bound-will-change-warning.nll.stderr
@@ -2,19 +2,29 @@ error[E0521]: borrowed data escapes outside of function
   --> $DIR/lifetime-bound-will-change-warning.rs:34:5
    |
 LL | fn test2<'a>(x: &'a Box<dyn Fn() + 'a>) {
-   |              - `x` is a reference that is only valid in the function body
+   |          --  - `x` is a reference that is only valid in the function body
+   |          |
+   |          lifetime `'a` defined here
 LL |     // but ref_obj will not, so warn.
 LL |     ref_obj(x)
-   |     ^^^^^^^^^^ `x` escapes the function body here
+   |     ^^^^^^^^^^
+   |     |
+   |     `x` escapes the function body here
+   |     argument requires that `'a` must outlive `'static`
 
 error[E0521]: borrowed data escapes outside of function
   --> $DIR/lifetime-bound-will-change-warning.rs:39:5
    |
 LL | fn test2cc<'a>(x: &'a Box<dyn Fn() + 'a>) {
-   |                - `x` is a reference that is only valid in the function body
+   |            --  - `x` is a reference that is only valid in the function body
+   |            |
+   |            lifetime `'a` defined here
 LL |     // same as test2, but cross crate
 LL |     lib::ref_obj(x)
-   |     ^^^^^^^^^^^^^^^ `x` escapes the function body here
+   |     ^^^^^^^^^^^^^^^
+   |     |
+   |     `x` escapes the function body here
+   |     argument requires that `'a` must outlive `'static`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr
index d17a40a95c1b8..d77793291c5c5 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr
@@ -38,14 +38,19 @@ error[E0521]: borrowed data escapes outside of function
   --> $DIR/propagate-approximated-shorter-to-static-no-bound.rs:32:5
    |
 LL |   fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
-   |                     ------ `cell_a` is a reference that is only valid in the function body
+   |             --      ------ `cell_a` is a reference that is only valid in the function body
+   |             |
+   |             lifetime `'a` defined here
 LL | /     establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
 LL | |
 LL | |
 LL | |         // Only works if 'x: 'y:
 LL | |         demand_y(x, y, x.get())
 LL | |     });
-   | |______^ `cell_a` escapes the function body here
+   | |      ^
+   | |      |
+   | |______`cell_a` escapes the function body here
+   |        argument requires that `'a` must outlive `'static`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr
index 06c46ec8259a0..cc67270ad20c1 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr
@@ -38,14 +38,19 @@ error[E0521]: borrowed data escapes outside of function
   --> $DIR/propagate-approximated-shorter-to-static-wrong-bound.rs:35:5
    |
 LL |   fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
-   |                     ------ `cell_a` is a reference that is only valid in the function body
+   |             --      ------ `cell_a` is a reference that is only valid in the function body
+   |             |
+   |             lifetime `'a` defined here
 LL | /     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y| {
 LL | |
 LL | |
 LL | |         // Only works if 'x: 'y:
 LL | |         demand_y(x, y, x.get())
 LL | |     });
-   | |______^ `cell_a` escapes the function body here
+   | |      ^
+   | |      |
+   | |______`cell_a` escapes the function body here
+   |        argument requires that `'a` must outlive `'static`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/nll/issue-67007-escaping-data.rs b/src/test/ui/nll/issue-67007-escaping-data.rs
new file mode 100644
index 0000000000000..8c21737e05fe8
--- /dev/null
+++ b/src/test/ui/nll/issue-67007-escaping-data.rs
@@ -0,0 +1,26 @@
+// Regression test for issue #67007
+// Ensures that we show information about the specific regions involved
+
+#![feature(nll)]
+
+// Covariant over 'a, invariant over 'tcx
+struct FnCtxt<'a, 'tcx: 'a>(&'a (), *mut &'tcx ());
+
+impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
+    fn use_it(&self, _: &'tcx ()) {}
+}
+
+struct Consumer<'tcx>(&'tcx ());
+
+impl<'tcx> Consumer<'tcx> {
+    fn bad_method<'a>(&self, fcx: &FnCtxt<'a, 'tcx>) {
+        let other = self.use_fcx(fcx); //~ ERROR borrowed data
+        fcx.use_it(other);
+    }
+
+    fn use_fcx<'a>(&self, _: &FnCtxt<'a, 'tcx>) -> &'a () {
+        &()
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/nll/issue-67007-escaping-data.stderr b/src/test/ui/nll/issue-67007-escaping-data.stderr
new file mode 100644
index 0000000000000..2834d6fb0d214
--- /dev/null
+++ b/src/test/ui/nll/issue-67007-escaping-data.stderr
@@ -0,0 +1,21 @@
+error[E0521]: borrowed data escapes outside of associated function
+  --> $DIR/issue-67007-escaping-data.rs:17:21
+   |
+LL | impl<'tcx> Consumer<'tcx> {
+   |      ---- lifetime `'tcx` defined here
+LL |     fn bad_method<'a>(&self, fcx: &FnCtxt<'a, 'tcx>) {
+   |                   --  -----  --- `fcx` is a reference that is only valid in the associated function body
+   |                   |   |
+   |                   |   `self` declared here, outside of the associated function body
+   |                   lifetime `'a` defined here
+LL |         let other = self.use_fcx(fcx);
+   |                     ^^^^^^^^^^^^^^^^^
+   |                     |
+   |                     `fcx` escapes the associated function body here
+   |                     argument requires that `'a` must outlive `'tcx`
+   |
+   = help: consider adding the following bound: `'a: 'tcx`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/nll/outlives-suggestion-simple.stderr b/src/test/ui/nll/outlives-suggestion-simple.stderr
index fa85ce2799083..3b2017d2d03a1 100644
--- a/src/test/ui/nll/outlives-suggestion-simple.stderr
+++ b/src/test/ui/nll/outlives-suggestion-simple.stderr
@@ -92,13 +92,20 @@ LL |         self.x
 error[E0521]: borrowed data escapes outside of associated function
   --> $DIR/outlives-suggestion-simple.rs:73:9
    |
+LL | impl<'a> Foo2<'a> {
+   |      -- lifetime `'a` defined here
+LL |     // should not produce outlives suggestions to name 'self
 LL |     fn get_bar(&self) -> Bar2 {
    |                -----
    |                |
    |                `self` declared here, outside of the associated function body
    |                `self` is a reference that is only valid in the associated function body
+   |                let's call the lifetime of this reference `'1`
 LL |         Bar2::new(&self)
-   |         ^^^^^^^^^^^^^^^^ `self` escapes the associated function body here
+   |         ^^^^^^^^^^^^^^^^
+   |         |
+   |         `self` escapes the associated function body here
+   |         argument requires that `'1` must outlive `'a`
 
 error: aborting due to 9 previous errors
 
diff --git a/src/test/ui/nll/user-annotations/closure-substs.stderr b/src/test/ui/nll/user-annotations/closure-substs.stderr
index 55bb3a6090c01..20002e4591d1a 100644
--- a/src/test/ui/nll/user-annotations/closure-substs.stderr
+++ b/src/test/ui/nll/user-annotations/closure-substs.stderr
@@ -28,9 +28,14 @@ error[E0521]: borrowed data escapes outside of closure
   --> $DIR/closure-substs.rs:29:9
    |
 LL |     |x: &i32, b: fn(&'static i32)| {
-   |      - `x` is a reference that is only valid in the closure body
+   |      -  - let's call the lifetime of this reference `'1`
+   |      |
+   |      `x` is a reference that is only valid in the closure body
 LL |         b(x);
-   |         ^^^^ `x` escapes the closure body here
+   |         ^^^^
+   |         |
+   |         `x` escapes the closure body here
+   |         argument requires that `'1` must outlive `'static`
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/object-lifetime/object-lifetime-default-mybox.nll.stderr b/src/test/ui/object-lifetime/object-lifetime-default-mybox.nll.stderr
index 6ce1b2eed85d2..af20c5e5fc0da 100644
--- a/src/test/ui/object-lifetime/object-lifetime-default-mybox.nll.stderr
+++ b/src/test/ui/object-lifetime/object-lifetime-default-mybox.nll.stderr
@@ -15,9 +15,14 @@ error[E0521]: borrowed data escapes outside of function
   --> $DIR/object-lifetime-default-mybox.rs:31:5
    |
 LL | fn load2<'a>(ss: &MyBox<dyn SomeTrait + 'a>) -> MyBox<dyn SomeTrait + 'a> {
-   |              -- `ss` is a reference that is only valid in the function body
+   |          --  -- `ss` is a reference that is only valid in the function body
+   |          |
+   |          lifetime `'a` defined here
 LL |     load0(ss)
-   |     ^^^^^^^^^ `ss` escapes the function body here
+   |     ^^^^^^^^^
+   |     |
+   |     `ss` escapes the function body here
+   |     argument requires that `'a` must outlive `'static`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/regions/issue-78262.nll.stderr b/src/test/ui/regions/issue-78262.nll.stderr
index a35d6fd9bf885..721dafac0be76 100644
--- a/src/test/ui/regions/issue-78262.nll.stderr
+++ b/src/test/ui/regions/issue-78262.nll.stderr
@@ -2,8 +2,11 @@ error[E0521]: borrowed data escapes outside of closure
   --> $DIR/issue-78262.rs:14:26
    |
 LL |     let f = |x: &dyn TT| x.func();
-   |              -           ^^^^^^^^ `x` escapes the closure body here
-   |              |
+   |              -  -        ^^^^^^^^
+   |              |  |        |
+   |              |  |        `x` escapes the closure body here
+   |              |  |        argument requires that `'1` must outlive `'static`
+   |              |  let's call the lifetime of this reference `'1`
    |              `x` is a reference that is only valid in the closure body
 
 error: aborting due to previous error
diff --git a/src/test/ui/regions/issue-78262.polonius.stderr b/src/test/ui/regions/issue-78262.polonius.stderr
index a35d6fd9bf885..721dafac0be76 100644
--- a/src/test/ui/regions/issue-78262.polonius.stderr
+++ b/src/test/ui/regions/issue-78262.polonius.stderr
@@ -2,8 +2,11 @@ error[E0521]: borrowed data escapes outside of closure
   --> $DIR/issue-78262.rs:14:26
    |
 LL |     let f = |x: &dyn TT| x.func();
-   |              -           ^^^^^^^^ `x` escapes the closure body here
-   |              |
+   |              -  -        ^^^^^^^^
+   |              |  |        |
+   |              |  |        `x` escapes the closure body here
+   |              |  |        argument requires that `'1` must outlive `'static`
+   |              |  let's call the lifetime of this reference `'1`
    |              `x` is a reference that is only valid in the closure body
 
 error: aborting due to previous error
diff --git a/src/test/ui/regions/region-invariant-static-error-reporting.nll.stderr b/src/test/ui/regions/region-invariant-static-error-reporting.nll.stderr
index 7221759dbd450..e220cbf555956 100644
--- a/src/test/ui/regions/region-invariant-static-error-reporting.nll.stderr
+++ b/src/test/ui/regions/region-invariant-static-error-reporting.nll.stderr
@@ -2,10 +2,15 @@ error[E0521]: borrowed data escapes outside of function
   --> $DIR/region-invariant-static-error-reporting.rs:15:9
    |
 LL | fn unify<'a>(x: Option<Invariant<'a>>, f: fn(Invariant<'a>)) {
-   |              - `x` is a reference that is only valid in the function body
+   |          --  - `x` is a reference that is only valid in the function body
+   |          |
+   |          lifetime `'a` defined here
 LL |     let bad = if x.is_some() {
 LL |         x.unwrap()
-   |         ^^^^^^^^^^ `x` escapes the function body here
+   |         ^^^^^^^^^^
+   |         |
+   |         `x` escapes the function body here
+   |         argument requires that `'a` must outlive `'static`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/regions/regions-bounded-method-type-parameters-trait-bound.nll.stderr b/src/test/ui/regions/regions-bounded-method-type-parameters-trait-bound.nll.stderr
index ed7b17c207c30..83d6e13dc0a68 100644
--- a/src/test/ui/regions/regions-bounded-method-type-parameters-trait-bound.nll.stderr
+++ b/src/test/ui/regions/regions-bounded-method-type-parameters-trait-bound.nll.stderr
@@ -2,12 +2,17 @@ error[E0521]: borrowed data escapes outside of function
   --> $DIR/regions-bounded-method-type-parameters-trait-bound.rs:20:5
    |
 LL | fn caller2<'a,'b,F:Foo<'a>>(a: Inv<'a>, b: Inv<'b>, f: F) {
-   |                             -           - `b` is a reference that is only valid in the function body
-   |                             |
-   |                             `a` declared here, outside of the function body
+   |            -- --            -           - `b` is a reference that is only valid in the function body
+   |            |  |             |
+   |            |  |             `a` declared here, outside of the function body
+   |            |  lifetime `'b` defined here
+   |            lifetime `'a` defined here
 LL |     // Here the value provided for 'y is 'b, and hence 'b:'a does not hold.
 LL |     f.method(b);
-   |     ^^^^^^^^^^^ `b` escapes the function body here
+   |     ^^^^^^^^^^^
+   |     |
+   |     `b` escapes the function body here
+   |     argument requires that `'b` must outlive `'a`
    |
    = help: consider adding the following bound: `'b: 'a`
 
diff --git a/src/test/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound.nll.stderr b/src/test/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound.nll.stderr
index 32a2de1e84d8f..a1ef32c5445b5 100644
--- a/src/test/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound.nll.stderr
+++ b/src/test/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound.nll.stderr
@@ -2,33 +2,53 @@ error[E0521]: borrowed data escapes outside of function
   --> $DIR/impl-on-dyn-trait-with-implicit-static-bound.rs:20:9
    |
 LL |     fn use_it<'a, T>(val: &'a dyn ObjectTrait<T>) -> impl OtherTrait<'a> + 'a {
-   |                      --- `val` is a reference that is only valid in the function body
+   |               --     --- `val` is a reference that is only valid in the function body
+   |               |
+   |               lifetime `'a` defined here
 LL |         val.use_self::<T>()
-   |         ^^^^^^^^^^^^^^^^^^^ `val` escapes the function body here
+   |         ^^^^^^^^^^^^^^^^^^^
+   |         |
+   |         `val` escapes the function body here
+   |         argument requires that `'a` must outlive `'static`
 
 error[E0521]: borrowed data escapes outside of function
   --> $DIR/impl-on-dyn-trait-with-implicit-static-bound.rs:69:9
    |
 LL |     fn use_it<'a>(val: &'a dyn ObjectTrait) -> impl OtherTrait<'a> + 'a {
-   |                   --- `val` is a reference that is only valid in the function body
+   |               --  --- `val` is a reference that is only valid in the function body
+   |               |
+   |               lifetime `'a` defined here
 LL |         val.use_self()
-   |         ^^^^^^^^^^^^^^ `val` escapes the function body here
+   |         ^^^^^^^^^^^^^^
+   |         |
+   |         `val` escapes the function body here
+   |         argument requires that `'a` must outlive `'static`
 
 error[E0521]: borrowed data escapes outside of function
   --> $DIR/impl-on-dyn-trait-with-implicit-static-bound.rs:88:9
    |
 LL |     fn use_it<'a>(val: &'a dyn ObjectTrait) -> impl OtherTrait<'a> {
-   |                   --- `val` is a reference that is only valid in the function body
+   |               --  --- `val` is a reference that is only valid in the function body
+   |               |
+   |               lifetime `'a` defined here
 LL |         val.use_self()
-   |         ^^^^^^^^^^^^^^ `val` escapes the function body here
+   |         ^^^^^^^^^^^^^^
+   |         |
+   |         `val` escapes the function body here
+   |         argument requires that `'a` must outlive `'static`
 
 error[E0521]: borrowed data escapes outside of function
   --> $DIR/impl-on-dyn-trait-with-implicit-static-bound.rs:108:9
    |
 LL |     fn use_it<'a>(val: &'a dyn ObjectTrait) -> impl OtherTrait<'a> + 'a {
-   |                   --- `val` is a reference that is only valid in the function body
+   |               --  --- `val` is a reference that is only valid in the function body
+   |               |
+   |               lifetime `'a` defined here
 LL |         MyTrait::use_self(val)
-   |         ^^^^^^^^^^^^^^^^^^^^^^ `val` escapes the function body here
+   |         ^^^^^^^^^^^^^^^^^^^^^^
+   |         |
+   |         `val` escapes the function body here
+   |         argument requires that `'a` must outlive `'static`
 
 error: aborting due to 4 previous errors
 

From edfd6d591b51da089b65c68ece0aecd1e9b8a42b Mon Sep 17 00:00:00 2001
From: Ellen <supbscripter@gmail.com>
Date: Wed, 6 Oct 2021 04:37:07 +0100
Subject: [PATCH 15/15] test

---
 .../const_eval_resolve_canonical.rs           | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 src/test/ui/const-generics/generic_const_exprs/const_eval_resolve_canonical.rs

diff --git a/src/test/ui/const-generics/generic_const_exprs/const_eval_resolve_canonical.rs b/src/test/ui/const-generics/generic_const_exprs/const_eval_resolve_canonical.rs
new file mode 100644
index 0000000000000..b79bc262d2bac
--- /dev/null
+++ b/src/test/ui/const-generics/generic_const_exprs/const_eval_resolve_canonical.rs
@@ -0,0 +1,29 @@
+// run-pass
+#![feature(generic_const_exprs)]
+#![allow(incomplete_features)]
+
+trait Foo<const N: usize> {
+    type Assoc: Default;
+}
+
+impl Foo<0> for () {
+    type Assoc = u32;
+}
+
+impl Foo<3> for () {
+    type Assoc = i64;
+}
+
+fn foo<T, const N: usize>(_: T) -> <() as Foo<{ N + 1 }>>::Assoc
+where
+    (): Foo<{ N + 1 }>,
+{
+    Default::default()
+}
+
+fn main() {
+    // Test that we can correctly infer `T` which requires evaluating
+    // `{ N + 1 }` which has substs containing an inference var
+    let mut _q = Default::default();
+    _q = foo::<_, 2>(_q);
+}