Merge ref '3f1552a273e4' from rust-lang/rust

Pull recent changes from https://github.com/rust-lang/rust via Josh.

Upstream ref: 3f1552a
Filtered ref: fbfa7b30a3ad5abd6a5db7e3ef15adc8da1ecc37
Upstream diff: rust-lang/rust@9d82de1...3f1552a

This merge was created using https://github.com/rust-lang/josh-sync.

Author: The Miri Cronjob Bot

alloc/src/vec/peek_mut.rs

@@ -29,9 +29,9 @@ impl<'a, T> PeekMut<'a, T> {
 
     /// Removes the peeked value from the vector and returns it.
     #[unstable(feature = "vec_peek_mut", issue = "122742")]
-    pub fn pop(self) -> T {
+    pub fn pop(this: Self) -> T {
         // SAFETY: PeekMut is only constructed if the vec is non-empty
-        unsafe { self.vec.pop().unwrap_unchecked() }
+        unsafe { this.vec.pop().unwrap_unchecked() }
     }
 }
 

alloctests/tests/vec.rs

@@ -15,7 +15,7 @@ use std::ops::Bound::*;
 use std::panic::{AssertUnwindSafe, catch_unwind};
 use std::rc::Rc;
 use std::sync::atomic::{AtomicU32, Ordering};
-use std::vec::{Drain, IntoIter};
+use std::vec::{Drain, IntoIter, PeekMut};
 
 use crate::testing::macros::struct_with_counted_drop;
 
@@ -2647,7 +2647,7 @@ fn test_peek_mut() {
         assert_eq!(*p, 2);
         *p = 0;
         assert_eq!(*p, 0);
-        p.pop();
+        PeekMut::pop(p);
         assert_eq!(vec.len(), 1);
     } else {
         unreachable!()

core/src/array/mod.rs

@@ -472,6 +472,11 @@ impl<T: Copy> SpecArrayClone for T {
 // The Default impls cannot be done with const generics because `[T; 0]` doesn't
 // require Default to be implemented, and having different impl blocks for
 // different numbers isn't supported yet.
+//
+// Trying to improve the `[T; 0]` situation has proven to be difficult.
+// Please see these issues for more context on past attempts and crater runs:
+// - https://github.com/rust-lang/rust/issues/61415
+// - https://github.com/rust-lang/rust/pull/145457
 
 macro_rules! array_impl_default {
     {$n:expr, $t:ident $($ts:ident)*} => {

core/src/cmp.rs

@@ -334,9 +334,8 @@ pub macro PartialEq($item:item) {
 #[doc(alias = "!=")]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "Eq"]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
-pub trait Eq: [const] PartialEq<Self> + PointeeSized {
+pub const trait Eq: [const] PartialEq<Self> + PointeeSized {
     // this method is used solely by `impl Eq or #[derive(Eq)]` to assert that every component of a
     // type implements `Eq` itself. The current deriving infrastructure means doing this assertion
     // without using a method on this trait is nearly impossible.
@@ -966,9 +965,8 @@ impl<T: Clone> Clone for Reverse<T> {
 #[doc(alias = ">=")]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "Ord"]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
-pub trait Ord: [const] Eq + [const] PartialOrd<Self> + PointeeSized {
+pub const trait Ord: [const] Eq + [const] PartialOrd<Self> + PointeeSized {
     /// This method returns an [`Ordering`] between `self` and `other`.
     ///
     /// By convention, `self.cmp(&other)` returns the ordering matching the expression
@@ -1352,9 +1350,8 @@ pub macro Ord($item:item) {
 )]
 #[rustc_diagnostic_item = "PartialOrd"]
 #[allow(multiple_supertrait_upcastable)] // FIXME(sized_hierarchy): remove this
-#[const_trait]
 #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
-pub trait PartialOrd<Rhs: PointeeSized = Self>: PartialEq<Rhs> + PointeeSized {
+pub const trait PartialOrd<Rhs: PointeeSized = Self>: PartialEq<Rhs> + PointeeSized {
     /// This method returns an ordering between `self` and `other` values if one exists.
     ///
     /// # Examples

core/src/marker.rs

@@ -1083,7 +1083,7 @@ pub trait Tuple {}
 // We name this differently than the derive macro so that the `adt_const_params` can
 // be used independently of `unsized_const_params` without requiring a full path
 // to the derive macro every time it is used. This should be renamed on stabilization.
-pub trait ConstParamTy_: UnsizedConstParamTy + StructuralPartialEq + Eq {}
+pub trait ConstParamTy_: StructuralPartialEq + Eq {}
 
 /// Derive macro generating an impl of the trait `ConstParamTy`.
 #[rustc_builtin_macro]
@@ -1093,23 +1093,6 @@ pub macro ConstParamTy($item:item) {
     /* compiler built-in */
 }
 
-#[lang = "unsized_const_param_ty"]
-#[unstable(feature = "unsized_const_params", issue = "95174")]
-#[diagnostic::on_unimplemented(message = "`{Self}` can't be used as a const parameter type")]
-/// A marker for types which can be used as types of `const` generic parameters.
-///
-/// Equivalent to [`ConstParamTy_`] except that this is used by
-/// the `unsized_const_params` to allow for fake unstable impls.
-pub trait UnsizedConstParamTy: StructuralPartialEq + Eq {}
-
-/// Derive macro generating an impl of the trait `ConstParamTy`.
-#[rustc_builtin_macro]
-#[allow_internal_unstable(unsized_const_params)]
-#[unstable(feature = "unsized_const_params", issue = "95174")]
-pub macro UnsizedConstParamTy($item:item) {
-    /* compiler built-in */
-}
-
 // FIXME(adt_const_params): handle `ty::FnDef`/`ty::Closure`
 marker_impls! {
     #[unstable(feature = "adt_const_params", issue = "95174")]
@@ -1124,17 +1107,11 @@ marker_impls! {
 
 marker_impls! {
     #[unstable(feature = "unsized_const_params", issue = "95174")]
-    UnsizedConstParamTy for
-        usize, u8, u16, u32, u64, u128,
-        isize, i8, i16, i32, i64, i128,
-        bool,
-        char,
-        (),
-        {T: UnsizedConstParamTy, const N: usize} [T; N],
-
+    #[unstable_feature_bound(unsized_const_params)]
+    ConstParamTy_ for
         str,
-        {T: UnsizedConstParamTy} [T],
-        {T: UnsizedConstParamTy + ?Sized} &T,
+        {T: ConstParamTy_} [T],
+        {T: ConstParamTy_ + ?Sized} &T,
 }
 
 /// A common trait implemented by all function pointers.

core/src/mem/transmutability.rs

@@ -1,4 +1,4 @@
-use crate::marker::{ConstParamTy_, UnsizedConstParamTy};
+use crate::marker::ConstParamTy_;
 
 /// Marks that `Src` is transmutable into `Self`.
 ///
@@ -83,6 +83,7 @@ use crate::marker::{ConstParamTy_, UnsizedConstParamTy};
 /// Furthermore, stability does not imply portability. For example, the size of
 /// `usize` is stable, but not portable.
 #[unstable(feature = "transmutability", issue = "99571")]
+#[unstable_feature_bound(transmutability)]
 #[lang = "transmute_trait"]
 #[rustc_deny_explicit_impl]
 #[rustc_do_not_implement_via_object]
@@ -288,9 +289,8 @@ pub struct Assume {
 }
 
 #[unstable(feature = "transmutability", issue = "99571")]
+#[unstable_feature_bound(transmutability)]
 impl ConstParamTy_ for Assume {}
-#[unstable(feature = "transmutability", issue = "99571")]
-impl UnsizedConstParamTy for Assume {}
 
 impl Assume {
     /// With this, [`TransmuteFrom`] does not assume you have ensured any safety

core/src/num/bignum.rs

@@ -335,43 +335,6 @@ macro_rules! define_bignum {
                 }
                 (self, borrow)
             }
-
-            /// Divide self by another bignum, overwriting `q` with the quotient and `r` with the
-            /// remainder.
-            pub fn div_rem(&self, d: &$name, q: &mut $name, r: &mut $name) {
-                // Stupid slow base-2 long division taken from
-                // https://en.wikipedia.org/wiki/Division_algorithm
-                // FIXME use a greater base ($ty) for the long division.
-                assert!(!d.is_zero());
-                let digitbits = <$ty>::BITS as usize;
-                for digit in &mut q.base[..] {
-                    *digit = 0;
-                }
-                for digit in &mut r.base[..] {
-                    *digit = 0;
-                }
-                r.size = d.size;
-                q.size = 1;
-                let mut q_is_zero = true;
-                let end = self.bit_length();
-                for i in (0..end).rev() {
-                    r.mul_pow2(1);
-                    r.base[0] |= self.get_bit(i) as $ty;
-                    if &*r >= d {
-                        r.sub(d);
-                        // Set bit `i` of q to 1.
-                        let digit_idx = i / digitbits;
-                        let bit_idx = i % digitbits;
-                        if q_is_zero {
-                            q.size = digit_idx + 1;
-                            q_is_zero = false;
-                        }
-                        q.base[digit_idx] |= 1 << bit_idx;
-                    }
-                }
-                debug_assert!(q.base[q.size..].iter().all(|&d| d == 0));
-                debug_assert!(r.base[r.size..].iter().all(|&d| d == 0));
-            }
         }
 
         impl crate::cmp::PartialEq for $name {

core/src/tuple.rs

@@ -1,7 +1,7 @@
 // See core/src/primitive_docs.rs for documentation.
 
 use crate::cmp::Ordering::{self, *};
-use crate::marker::{ConstParamTy_, StructuralPartialEq, UnsizedConstParamTy};
+use crate::marker::{ConstParamTy_, StructuralPartialEq};
 use crate::ops::ControlFlow::{self, Break, Continue};
 
 // Recursive macro for implementing n-ary tuple functions and operations
@@ -47,17 +47,11 @@ macro_rules! tuple_impls {
         maybe_tuple_doc! {
             $($T)+ @
             #[unstable(feature = "adt_const_params", issue = "95174")]
+            #[unstable_feature_bound(unsized_const_params)]
             impl<$($T: ConstParamTy_),+> ConstParamTy_ for ($($T,)+)
             {}
         }
 
-        maybe_tuple_doc! {
-            $($T)+ @
-            #[unstable(feature = "unsized_const_params", issue = "95174")]
-            impl<$($T: UnsizedConstParamTy),+> UnsizedConstParamTy for ($($T,)+)
-            {}
-        }
-
         maybe_tuple_doc! {
             $($T)+ @
             #[unstable(feature = "structural_match", issue = "31434")]

coretests/tests/ascii.rs

@@ -505,3 +505,10 @@ fn test_escape_ascii_iter() {
     let _ = it.advance_back_by(4);
     assert_eq!(it.to_string(), r#"fastpath\xffremainder"#);
 }
+
+#[test]
+fn test_invalid_u8() {
+    for c in 128..=255 {
+        assert_eq!(core::ascii::Char::from_u8(c), None);
+    }
+}

coretests/tests/fmt/builders.rs

@@ -173,6 +173,21 @@ mod debug_struct {
             format!("{Bar:#?}")
         );
     }
+
+    #[test]
+    fn test_field_with() {
+        struct Foo;
+        impl fmt::Debug for Foo {
+            fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+                fmt.debug_struct("Foo")
+                    .field_with("bar", |f| f.write_str("true"))
+                    .field_with("baz", |f| f.write_str("false"))
+                    .finish()
+            }
+        }
+
+        assert_eq!("Foo {\n    bar: true,\n    baz: false,\n}", format!("{Foo:#?}"))
+    }
 }
 
 mod debug_tuple {