Rollup of 5 pull requests

src/liballoc/rc.rs

@@ -2034,7 +2034,7 @@ trait RcBoxPtr<T: ?Sized> {
         // The reference count will never be zero when this is called;
         // nevertheless, we insert an abort here to hint LLVM at
         // an otherwise missed optimization.
-        if strong == 0 || strong == usize::max_value() {
+        if strong == 0 || strong == usize::MAX {
             abort();
         }
         self.inner().strong.set(strong + 1);
@@ -2058,7 +2058,7 @@ trait RcBoxPtr<T: ?Sized> {
         // The reference count will never be zero when this is called;
         // nevertheless, we insert an abort here to hint LLVM at
         // an otherwise missed optimization.
-        if weak == 0 || weak == usize::max_value() {
+        if weak == 0 || weak == usize::MAX {
             abort();
         }
         self.inner().weak.set(weak + 1);

src/liballoc/rc/tests.rs

@@ -407,14 +407,14 @@ fn test_from_vec() {
 fn test_downcast() {
     use std::any::Any;
 
-    let r1: Rc<dyn Any> = Rc::new(i32::max_value());
+    let r1: Rc<dyn Any> = Rc::new(i32::MAX);
     let r2: Rc<dyn Any> = Rc::new("abc");
 
     assert!(r1.clone().downcast::<u32>().is_err());
 
     let r1i32 = r1.downcast::<i32>();
     assert!(r1i32.is_ok());
-    assert_eq!(r1i32.unwrap(), Rc::new(i32::max_value()));
+    assert_eq!(r1i32.unwrap(), Rc::new(i32::MAX));
 
     assert!(r2.clone().downcast::<i32>().is_err());
 

src/liballoc/sync/tests.rs

@@ -465,14 +465,14 @@ fn test_from_vec() {
 fn test_downcast() {
     use std::any::Any;
 
-    let r1: Arc<dyn Any + Send + Sync> = Arc::new(i32::max_value());
+    let r1: Arc<dyn Any + Send + Sync> = Arc::new(i32::MAX);
     let r2: Arc<dyn Any + Send + Sync> = Arc::new("abc");
 
     assert!(r1.clone().downcast::<u32>().is_err());
 
     let r1i32 = r1.downcast::<i32>();
     assert!(r1i32.is_ok());
-    assert_eq!(r1i32.unwrap(), Arc::new(i32::max_value()));
+    assert_eq!(r1i32.unwrap(), Arc::new(i32::MAX));
 
     assert!(r2.clone().downcast::<i32>().is_err());
 

src/liballoc/tests/str.rs

@@ -566,13 +566,13 @@ mod slice_index {
                 data: "hello";
                 // note: using 0 specifically ensures that the result of overflowing is 0..0,
                 //       so that `get` doesn't simply return None for the wrong reason.
-                bad: data[0..=usize::max_value()];
+                bad: data[0..=usize::MAX];
                 message: "maximum usize";
             }
 
             in mod rangetoinclusive {
                 data: "hello";
-                bad: data[..=usize::max_value()];
+                bad: data[..=usize::MAX];
                 message: "maximum usize";
             }
         }

src/liballoc/tests/vec.rs

@@ -68,7 +68,7 @@ fn test_reserve() {
 
 #[test]
 fn test_zst_capacity() {
-    assert_eq!(Vec::<()>::new().capacity(), usize::max_value());
+    assert_eq!(Vec::<()>::new().capacity(), usize::MAX);
 }
 
 #[test]
@@ -563,19 +563,19 @@ fn test_drain_inclusive_range() {
 
 #[test]
 fn test_drain_max_vec_size() {
-    let mut v = Vec::<()>::with_capacity(usize::max_value());
+    let mut v = Vec::<()>::with_capacity(usize::MAX);
     unsafe {
-        v.set_len(usize::max_value());
+        v.set_len(usize::MAX);
     }
-    for _ in v.drain(usize::max_value() - 1..) {}
-    assert_eq!(v.len(), usize::max_value() - 1);
+    for _ in v.drain(usize::MAX - 1..) {}
+    assert_eq!(v.len(), usize::MAX - 1);
 
-    let mut v = Vec::<()>::with_capacity(usize::max_value());
+    let mut v = Vec::<()>::with_capacity(usize::MAX);
     unsafe {
-        v.set_len(usize::max_value());
+        v.set_len(usize::MAX);
     }
-    for _ in v.drain(usize::max_value() - 1..=usize::max_value() - 1) {}
-    assert_eq!(v.len(), usize::max_value() - 1);
+    for _ in v.drain(usize::MAX - 1..=usize::MAX - 1) {}
+    assert_eq!(v.len(), usize::MAX - 1);
 }
 
 #[test]

src/libcore/cell.rs

@@ -1163,16 +1163,16 @@ impl<'b> BorrowRef<'b> {
             // Incrementing borrow can result in a non-reading value (<= 0) in these cases:
             // 1. It was < 0, i.e. there are writing borrows, so we can't allow a read borrow
             //    due to Rust's reference aliasing rules
-            // 2. It was isize::max_value() (the max amount of reading borrows) and it overflowed
-            //    into isize::min_value() (the max amount of writing borrows) so we can't allow
+            // 2. It was isize::MAX (the max amount of reading borrows) and it overflowed
+            //    into isize::MIN (the max amount of writing borrows) so we can't allow
             //    an additional read borrow because isize can't represent so many read borrows
             //    (this can only happen if you mem::forget more than a small constant amount of
             //    `Ref`s, which is not good practice)
             None
         } else {
             // Incrementing borrow can result in a reading value (> 0) in these cases:
             // 1. It was = 0, i.e. it wasn't borrowed, and we are taking the first read borrow
-            // 2. It was > 0 and < isize::max_value(), i.e. there were read borrows, and isize
+            // 2. It was > 0 and < isize::MAX, i.e. there were read borrows, and isize
             //    is large enough to represent having one more read borrow
             borrow.set(b);
             Some(BorrowRef { borrow })
@@ -1198,7 +1198,7 @@ impl Clone for BorrowRef<'_> {
         debug_assert!(is_reading(borrow));
         // Prevent the borrow counter from overflowing into
         // a writing borrow.
-        assert!(borrow != isize::max_value());
+        assert!(borrow != isize::MAX);
         self.borrow.set(borrow + 1);
         BorrowRef { borrow: self.borrow }
     }
@@ -1489,7 +1489,7 @@ impl<'b> BorrowRefMut<'b> {
         let borrow = self.borrow.get();
         debug_assert!(is_writing(borrow));
         // Prevent the borrow counter from underflowing.
-        assert!(borrow != isize::min_value());
+        assert!(borrow != isize::MIN);
         self.borrow.set(borrow - 1);
         BorrowRefMut { borrow: self.borrow }
     }

src/libcore/convert/num.rs

@@ -217,7 +217,7 @@ macro_rules! try_from_upper_bounded {
             /// is outside of the range of the target type.
             #[inline]
             fn try_from(u: $source) -> Result<Self, Self::Error> {
-                if u > (Self::max_value() as $source) {
+                if u > (Self::MAX as $source) {
                     Err(TryFromIntError(()))
                 } else {
                     Ok(u as Self)
@@ -239,8 +239,8 @@ macro_rules! try_from_both_bounded {
             /// is outside of the range of the target type.
             #[inline]
             fn try_from(u: $source) -> Result<Self, Self::Error> {
-                let min = Self::min_value() as $source;
-                let max = Self::max_value() as $source;
+                let min = Self::MIN as $source;
+                let max = Self::MAX as $source;
                 if u < min || u > max {
                     Err(TryFromIntError(()))
                 } else {

src/libcore/lib.rs

@@ -84,6 +84,8 @@
 #![feature(constctlz)]
 #![feature(const_panic)]
 #![feature(const_fn_union)]
+#![feature(const_float_bits_conv)]
+#![feature(const_float_classify)]
 #![feature(const_generics)]
 #![feature(const_ptr_offset)]
 #![feature(const_ptr_offset_from)]

src/libcore/num/f32.rs

@@ -381,16 +381,18 @@ impl f32 {
     /// assert!(!f.is_nan());
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")]
     #[inline]
-    pub fn is_nan(self) -> bool {
+    pub const fn is_nan(self) -> bool {
         self != self
     }
 
     // FIXME(#50145): `abs` is publicly unavailable in libcore due to
     // concerns about portability, so this implementation is for
     // private use internally.
+    #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")]
     #[inline]
-    fn abs_private(self) -> f32 {
+    const fn abs_private(self) -> f32 {
         f32::from_bits(self.to_bits() & 0x7fff_ffff)
     }
 
@@ -410,8 +412,9 @@ impl f32 {
     /// assert!(neg_inf.is_infinite());
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")]
     #[inline]
-    pub fn is_infinite(self) -> bool {
+    pub const fn is_infinite(self) -> bool {
         self.abs_private() == Self::INFINITY
     }
 
@@ -430,8 +433,9 @@ impl f32 {
     /// assert!(!neg_inf.is_finite());
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")]
     #[inline]
-    pub fn is_finite(self) -> bool {
+    pub const fn is_finite(self) -> bool {
         // There's no need to handle NaN separately: if self is NaN,
         // the comparison is not true, exactly as desired.
         self.abs_private() < Self::INFINITY
@@ -457,9 +461,10 @@ impl f32 {
     /// ```
     /// [subnormal]: https://en.wikipedia.org/wiki/Denormal_number
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")]
     #[inline]
-    pub fn is_normal(self) -> bool {
-        self.classify() == FpCategory::Normal
+    pub const fn is_normal(self) -> bool {
+        matches!(self.classify(), FpCategory::Normal)
     }
 
     /// Returns the floating point category of the number. If only one property
@@ -476,7 +481,8 @@ impl f32 {
     /// assert_eq!(inf.classify(), FpCategory::Infinite);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn classify(self) -> FpCategory {
+    #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")]
+    pub const fn classify(self) -> FpCategory {
         const EXP_MASK: u32 = 0x7f800000;
         const MAN_MASK: u32 = 0x007fffff;
 
@@ -501,8 +507,9 @@ impl f32 {
     /// assert!(!g.is_sign_positive());
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")]
     #[inline]
-    pub fn is_sign_positive(self) -> bool {
+    pub const fn is_sign_positive(self) -> bool {
         !self.is_sign_negative()
     }
 
@@ -517,8 +524,9 @@ impl f32 {
     /// assert!(g.is_sign_negative());
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")]
     #[inline]
-    pub fn is_sign_negative(self) -> bool {
+    pub const fn is_sign_negative(self) -> bool {
         // IEEE754 says: isSignMinus(x) is true if and only if x has negative sign. isSignMinus
         // applies to zeros and NaNs as well.
         self.to_bits() & 0x8000_0000 != 0
@@ -650,8 +658,9 @@ impl f32 {
     ///
     /// ```
     #[stable(feature = "float_bits_conv", since = "1.20.0")]
+    #[rustc_const_unstable(feature = "const_float_bits_conv", issue = "72447")]
     #[inline]
-    pub fn to_bits(self) -> u32 {
+    pub const fn to_bits(self) -> u32 {
         // SAFETY: `u32` is a plain old datatype so we can always transmute to it
         unsafe { mem::transmute(self) }
     }
@@ -693,8 +702,9 @@ impl f32 {
     /// assert_eq!(v, 12.5);
     /// ```
     #[stable(feature = "float_bits_conv", since = "1.20.0")]
+    #[rustc_const_unstable(feature = "const_float_bits_conv", issue = "72447")]
     #[inline]
-    pub fn from_bits(v: u32) -> Self {
+    pub const fn from_bits(v: u32) -> Self {
         // SAFETY: `u32` is a plain old datatype so we can always transmute from it
         // It turns out the safety issues with sNaN were overblown! Hooray!
         unsafe { mem::transmute(v) }
@@ -710,8 +720,9 @@ impl f32 {
     /// assert_eq!(bytes, [0x41, 0x48, 0x00, 0x00]);
     /// ```
     #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
+    #[rustc_const_unstable(feature = "const_float_bits_conv", issue = "72447")]
     #[inline]
-    pub fn to_be_bytes(self) -> [u8; 4] {
+    pub const fn to_be_bytes(self) -> [u8; 4] {
         self.to_bits().to_be_bytes()
     }
 
@@ -725,8 +736,9 @@ impl f32 {
     /// assert_eq!(bytes, [0x00, 0x00, 0x48, 0x41]);
     /// ```
     #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
+    #[rustc_const_unstable(feature = "const_float_bits_conv", issue = "72447")]
     #[inline]
-    pub fn to_le_bytes(self) -> [u8; 4] {
+    pub const fn to_le_bytes(self) -> [u8; 4] {
         self.to_bits().to_le_bytes()
     }
 
@@ -753,8 +765,9 @@ impl f32 {
     /// );
     /// ```
     #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
+    #[rustc_const_unstable(feature = "const_float_bits_conv", issue = "72447")]
     #[inline]
-    pub fn to_ne_bytes(self) -> [u8; 4] {
+    pub const fn to_ne_bytes(self) -> [u8; 4] {
         self.to_bits().to_ne_bytes()
     }
 
@@ -767,8 +780,9 @@ impl f32 {
     /// assert_eq!(value, 12.5);
     /// ```
     #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
+    #[rustc_const_unstable(feature = "const_float_bits_conv", issue = "72447")]
     #[inline]
-    pub fn from_be_bytes(bytes: [u8; 4]) -> Self {
+    pub const fn from_be_bytes(bytes: [u8; 4]) -> Self {
         Self::from_bits(u32::from_be_bytes(bytes))
     }
 
@@ -781,8 +795,9 @@ impl f32 {
     /// assert_eq!(value, 12.5);
     /// ```
     #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
+    #[rustc_const_unstable(feature = "const_float_bits_conv", issue = "72447")]
     #[inline]
-    pub fn from_le_bytes(bytes: [u8; 4]) -> Self {
+    pub const fn from_le_bytes(bytes: [u8; 4]) -> Self {
         Self::from_bits(u32::from_le_bytes(bytes))
     }
 
@@ -806,8 +821,9 @@ impl f32 {
     /// assert_eq!(value, 12.5);
     /// ```
     #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
+    #[rustc_const_unstable(feature = "const_float_bits_conv", issue = "72447")]
     #[inline]
-    pub fn from_ne_bytes(bytes: [u8; 4]) -> Self {
+    pub const fn from_ne_bytes(bytes: [u8; 4]) -> Self {
         Self::from_bits(u32::from_ne_bytes(bytes))
     }