Rollup merge of #108299 - scottmcm:literal-bits, r=Nilstrieb

Require `literal`s for some `(u)int_impl!` parameters

The point of these is to be seen *lexically* in the docs, so they should always be passed as the correct literal, not as an expression.

(Otherwise we could just compute `Min`/`Max` from `BITS`, for example.)

r? Nilstrieb
This commit is contained in:
Matthias Krüger 2023-02-26 12:04:57 +01:00 committed by GitHub
commit 3d2319f1d6
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2 changed files with 46 additions and 36 deletions

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@ -3,21 +3,26 @@ macro_rules! int_impl {
Self = $SelfT:ty,
ActualT = $ActualT:ident,
UnsignedT = $UnsignedT:ty,
BITS = $BITS:expr,
BITS_MINUS_ONE = $BITS_MINUS_ONE:expr,
Min = $Min:expr,
Max = $Max:expr,
rot = $rot:expr,
rot_op = $rot_op:expr,
rot_result = $rot_result:expr,
swap_op = $swap_op:expr,
swapped = $swapped:expr,
reversed = $reversed:expr,
le_bytes = $le_bytes:expr,
be_bytes = $be_bytes:expr,
// There are all for use *only* in doc comments.
// As such, they're all passed as literals -- passing them as a string
// literal is fine if they need to be multiple code tokens.
// In non-comments, use the associated constants rather than these.
BITS = $BITS:literal,
BITS_MINUS_ONE = $BITS_MINUS_ONE:literal,
Min = $Min:literal,
Max = $Max:literal,
rot = $rot:literal,
rot_op = $rot_op:literal,
rot_result = $rot_result:literal,
swap_op = $swap_op:literal,
swapped = $swapped:literal,
reversed = $reversed:literal,
le_bytes = $le_bytes:literal,
be_bytes = $be_bytes:literal,
to_xe_bytes_doc = $to_xe_bytes_doc:expr,
from_xe_bytes_doc = $from_xe_bytes_doc:expr,
bound_condition = $bound_condition:expr,
bound_condition = $bound_condition:literal,
) => {
/// The smallest value that can be represented by this integer type
#[doc = concat!("(&minus;2<sup>", $BITS_MINUS_ONE, "</sup>", $bound_condition, ").")]
@ -30,7 +35,7 @@ macro_rules! int_impl {
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN, ", stringify!($Min), ");")]
/// ```
#[stable(feature = "assoc_int_consts", since = "1.43.0")]
pub const MIN: Self = !0 ^ ((!0 as $UnsignedT) >> 1) as Self;
pub const MIN: Self = !Self::MAX;
/// The largest value that can be represented by this integer type
#[doc = concat!("(2<sup>", $BITS_MINUS_ONE, "</sup> &minus; 1", $bound_condition, ").")]
@ -43,7 +48,7 @@ macro_rules! int_impl {
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX, ", stringify!($Max), ");")]
/// ```
#[stable(feature = "assoc_int_consts", since = "1.43.0")]
pub const MAX: Self = !Self::MIN;
pub const MAX: Self = (<$UnsignedT>::MAX >> 1) as Self;
/// The size of this integer type in bits.
///
@ -53,7 +58,7 @@ macro_rules! int_impl {
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::BITS, ", stringify!($BITS), ");")]
/// ```
#[stable(feature = "int_bits_const", since = "1.53.0")]
pub const BITS: u32 = $BITS;
pub const BITS: u32 = <$UnsignedT>::BITS;
/// Converts a string slice in a given base to an integer.
///
@ -1380,7 +1385,7 @@ pub const fn wrapping_shl(self, rhs: u32) -> Self {
// SAFETY: the masking by the bitsize of the type ensures that we do not shift
// out of bounds
unsafe {
self.unchecked_shl(rhs & ($BITS - 1))
self.unchecked_shl(rhs & (Self::BITS - 1))
}
}
@ -1410,7 +1415,7 @@ pub const fn wrapping_shr(self, rhs: u32) -> Self {
// SAFETY: the masking by the bitsize of the type ensures that we do not shift
// out of bounds
unsafe {
self.unchecked_shr(rhs & ($BITS - 1))
self.unchecked_shr(rhs & (Self::BITS - 1))
}
}
@ -1916,7 +1921,7 @@ pub const fn overflowing_neg(self) -> (Self, bool) {
without modifying the original"]
#[inline]
pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
(self.wrapping_shl(rhs), (rhs > ($BITS - 1)))
(self.wrapping_shl(rhs), rhs >= Self::BITS)
}
/// Shifts self right by `rhs` bits.
@ -1939,7 +1944,7 @@ pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
without modifying the original"]
#[inline]
pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
(self.wrapping_shr(rhs), (rhs > ($BITS - 1)))
(self.wrapping_shr(rhs), rhs >= Self::BITS)
}
/// Computes the absolute value of `self`.

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@ -4,19 +4,24 @@ macro_rules! uint_impl {
ActualT = $ActualT:ident,
SignedT = $SignedT:ident,
NonZeroT = $NonZeroT:ident,
BITS = $BITS:expr,
MAX = $MaxV:expr,
rot = $rot:expr,
rot_op = $rot_op:expr,
rot_result = $rot_result:expr,
swap_op = $swap_op:expr,
swapped = $swapped:expr,
reversed = $reversed:expr,
le_bytes = $le_bytes:expr,
be_bytes = $be_bytes:expr,
// There are all for use *only* in doc comments.
// As such, they're all passed as literals -- passing them as a string
// literal is fine if they need to be multiple code tokens.
// In non-comments, use the associated constants rather than these.
BITS = $BITS:literal,
MAX = $MaxV:literal,
rot = $rot:literal,
rot_op = $rot_op:literal,
rot_result = $rot_result:literal,
swap_op = $swap_op:literal,
swapped = $swapped:literal,
reversed = $reversed:literal,
le_bytes = $le_bytes:literal,
be_bytes = $be_bytes:literal,
to_xe_bytes_doc = $to_xe_bytes_doc:expr,
from_xe_bytes_doc = $from_xe_bytes_doc:expr,
bound_condition = $bound_condition:expr,
bound_condition = $bound_condition:literal,
) => {
/// The smallest value that can be represented by this integer type.
///
@ -51,7 +56,7 @@ macro_rules! uint_impl {
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::BITS, ", stringify!($BITS), ");")]
/// ```
#[stable(feature = "int_bits_const", since = "1.53.0")]
pub const BITS: u32 = $BITS;
pub const BITS: u32 = Self::MAX.count_ones();
/// Converts a string slice in a given base to an integer.
///
@ -1403,7 +1408,7 @@ pub const fn wrapping_shl(self, rhs: u32) -> Self {
// SAFETY: the masking by the bitsize of the type ensures that we do not shift
// out of bounds
unsafe {
self.unchecked_shl(rhs & ($BITS - 1))
self.unchecked_shl(rhs & (Self::BITS - 1))
}
}
@ -1436,7 +1441,7 @@ pub const fn wrapping_shr(self, rhs: u32) -> Self {
// SAFETY: the masking by the bitsize of the type ensures that we do not shift
// out of bounds
unsafe {
self.unchecked_shr(rhs & ($BITS - 1))
self.unchecked_shr(rhs & (Self::BITS - 1))
}
}
@ -1860,7 +1865,7 @@ pub const fn overflowing_neg(self) -> (Self, bool) {
without modifying the original"]
#[inline(always)]
pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
(self.wrapping_shl(rhs), (rhs > ($BITS - 1)))
(self.wrapping_shl(rhs), rhs >= Self::BITS)
}
/// Shifts self right by `rhs` bits.
@ -1885,7 +1890,7 @@ pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
without modifying the original"]
#[inline(always)]
pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
(self.wrapping_shr(rhs), (rhs > ($BITS - 1)))
(self.wrapping_shr(rhs), rhs >= Self::BITS)
}
/// Raises self to the power of `exp`, using exponentiation by squaring.