library/core/src/convert/num.rs

   1 use super::{From, TryFrom};
   2 use crate::num::TryFromIntError;
   3
   4 mod private {
   5     /// This trait being unreachable from outside the crate
   6     /// prevents other implementations of the `FloatToInt` trait,
   7     /// which allows potentially adding more trait methods after the trait is `#[stable]`.
   8     #[unstable(feature = "convert_float_to_int", issue = "67057")]
   9     pub trait Sealed {}
  10 }
  11
  12 /// Supporting trait for inherent methods of `f32` and `f64` such as `to_int_unchecked`.
  13 /// Typically doesn’t need to be used directly.
  14 #[unstable(feature = "convert_float_to_int", issue = "67057")]
  15 pub trait FloatToInt<Int>: private::Sealed + Sized {
  16     #[unstable(feature = "convert_float_to_int", issue = "67057")]
  17     #[doc(hidden)]
  18     unsafe fn to_int_unchecked(self) -> Int;
  19 }
  20
  21 macro_rules! impl_float_to_int {
  22     ( $Float: ident => $( $Int: ident )+ ) => {
  23         #[unstable(feature = "convert_float_to_int", issue = "67057")]
  24         impl private::Sealed for $Float {}
  25         $(
  26             #[unstable(feature = "convert_float_to_int", issue = "67057")]
  27             impl FloatToInt<$Int> for $Float {
  28                 #[doc(hidden)]
  29                 #[inline]
  30                 unsafe fn to_int_unchecked(self) -> $Int {
  31                     // SAFETY: the safety contract must be upheld by the caller.
  32                     unsafe { crate::intrinsics::float_to_int_unchecked(self) }
  33                 }
  34             }
  35         )+
  36     }
  37 }
  38
  39 impl_float_to_int!(f32 => u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize);
  40 impl_float_to_int!(f64 => u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize);
  41
  42 // Conversion traits for primitive integer and float types
  43 // Conversions T -> T are covered by a blanket impl and therefore excluded
  44 // Some conversions from and to usize/isize are not implemented due to portability concerns
  45 macro_rules! impl_from {
  46     ($Small: ty, $Large: ty, #[$attr:meta], $doc: expr) => {
  47         #[$attr]
  48         #[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
  49         impl const From<$Small> for $Large {
  50             // Rustdocs on the impl block show a "[+] show undocumented items" toggle.
  51             // Rustdocs on functions do not.
  52             #[doc = $doc]
  53             #[inline]
  54             fn from(small: $Small) -> Self {
  55                 small as Self
  56             }
  57         }
  58     };
  59     ($Small: ty, $Large: ty, #[$attr:meta]) => {
  60         impl_from!($Small,
  61                    $Large,
  62                    #[$attr],
  63                    concat!("Converts `",
  64                            stringify!($Small),
  65                            "` to `",
  66                            stringify!($Large),
  67                            "` losslessly."));
  68     }
  69 }
  70
  71 macro_rules! impl_from_bool {
  72     ($target: ty, #[$attr:meta]) => {
  73         impl_from!(bool, $target, #[$attr], concat!("Converts a `bool` to a `",
  74             stringify!($target), "`. The resulting value is `0` for `false` and `1` for `true`
  75 values.
  76
  77 # Examples
  78
  79 ```
  80 assert_eq!(", stringify!($target), "::from(true), 1);
  81 assert_eq!(", stringify!($target), "::from(false), 0);
  82 ```"));
  83     };
  84 }
  85
  86 // Bool -> Any
  87 impl_from_bool! { u8, #[stable(feature = "from_bool", since = "1.28.0")] }
  88 impl_from_bool! { u16, #[stable(feature = "from_bool", since = "1.28.0")] }
  89 impl_from_bool! { u32, #[stable(feature = "from_bool", since = "1.28.0")] }
  90 impl_from_bool! { u64, #[stable(feature = "from_bool", since = "1.28.0")] }
  91 impl_from_bool! { u128, #[stable(feature = "from_bool", since = "1.28.0")] }
  92 impl_from_bool! { usize, #[stable(feature = "from_bool", since = "1.28.0")] }
  93 impl_from_bool! { i8, #[stable(feature = "from_bool", since = "1.28.0")] }
  94 impl_from_bool! { i16, #[stable(feature = "from_bool", since = "1.28.0")] }
  95 impl_from_bool! { i32, #[stable(feature = "from_bool", since = "1.28.0")] }
  96 impl_from_bool! { i64, #[stable(feature = "from_bool", since = "1.28.0")] }
  97 impl_from_bool! { i128, #[stable(feature = "from_bool", since = "1.28.0")] }
  98 impl_from_bool! { isize, #[stable(feature = "from_bool", since = "1.28.0")] }
  99
 100 // Unsigned -> Unsigned
 101 impl_from! { u8, u16, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 102 impl_from! { u8, u32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 103 impl_from! { u8, u64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 104 impl_from! { u8, u128, #[stable(feature = "i128", since = "1.26.0")] }
 105 impl_from! { u8, usize, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 106 impl_from! { u16, u32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 107 impl_from! { u16, u64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 108 impl_from! { u16, u128, #[stable(feature = "i128", since = "1.26.0")] }
 109 impl_from! { u32, u64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 110 impl_from! { u32, u128, #[stable(feature = "i128", since = "1.26.0")] }
 111 impl_from! { u64, u128, #[stable(feature = "i128", since = "1.26.0")] }
 112
 113 // Signed -> Signed
 114 impl_from! { i8, i16, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 115 impl_from! { i8, i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 116 impl_from! { i8, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 117 impl_from! { i8, i128, #[stable(feature = "i128", since = "1.26.0")] }
 118 impl_from! { i8, isize, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 119 impl_from! { i16, i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 120 impl_from! { i16, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 121 impl_from! { i16, i128, #[stable(feature = "i128", since = "1.26.0")] }
 122 impl_from! { i32, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 123 impl_from! { i32, i128, #[stable(feature = "i128", since = "1.26.0")] }
 124 impl_from! { i64, i128, #[stable(feature = "i128", since = "1.26.0")] }
 125
 126 // Unsigned -> Signed
 127 impl_from! { u8, i16, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 128 impl_from! { u8, i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 129 impl_from! { u8, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 130 impl_from! { u8, i128, #[stable(feature = "i128", since = "1.26.0")] }
 131 impl_from! { u16, i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 132 impl_from! { u16, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 133 impl_from! { u16, i128, #[stable(feature = "i128", since = "1.26.0")] }
 134 impl_from! { u32, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 135 impl_from! { u32, i128, #[stable(feature = "i128", since = "1.26.0")] }
 136 impl_from! { u64, i128, #[stable(feature = "i128", since = "1.26.0")] }
 137
 138 // The C99 standard defines bounds on INTPTR_MIN, INTPTR_MAX, and UINTPTR_MAX
 139 // which imply that pointer-sized integers must be at least 16 bits:
 140 // https://port70.net/~nsz/c/c99/n1256.html#7.18.2.4
 141 impl_from! { u16, usize, #[stable(feature = "lossless_iusize_conv", since = "1.26.0")] }
 142 impl_from! { u8, isize, #[stable(feature = "lossless_iusize_conv", since = "1.26.0")] }
 143 impl_from! { i16, isize, #[stable(feature = "lossless_iusize_conv", since = "1.26.0")] }
 144
 145 // RISC-V defines the possibility of a 128-bit address space (RV128).
 146
 147 // CHERI proposes 256-bit “capabilities”. Unclear if this would be relevant to usize/isize.
 148 // https://www.cl.cam.ac.uk/research/security/ctsrd/pdfs/20171017a-cheri-poster.pdf
 149 // https://www.csl.sri.com/users/neumann/2012resolve-cheri.pdf
 150
 151 // Note: integers can only be represented with full precision in a float if
 152 // they fit in the significand, which is 24 bits in f32 and 53 bits in f64.
 153 // Lossy float conversions are not implemented at this time.
 154
 155 // Signed -> Float
 156 impl_from! { i8, f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 157 impl_from! { i8, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 158 impl_from! { i16, f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 159 impl_from! { i16, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 160 impl_from! { i32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 161
 162 // Unsigned -> Float
 163 impl_from! { u8, f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 164 impl_from! { u8, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 165 impl_from! { u16, f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 166 impl_from! { u16, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 167 impl_from! { u32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 168
 169 // Float -> Float
 170 impl_from! { f32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 171
 172 // no possible bounds violation
 173 macro_rules! try_from_unbounded {
 174     ($source:ty, $($target:ty),*) => {$(
 175         #[stable(feature = "try_from", since = "1.34.0")]
 176         #[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
 177         impl const TryFrom<$source> for $target {
 178             type Error = TryFromIntError;
 179
 180             /// Try to create the target number type from a source
 181             /// number type. This returns an error if the source value
 182             /// is outside of the range of the target type.
 183             #[inline]
 184             fn try_from(value: $source) -> Result<Self, Self::Error> {
 185                 Ok(value as Self)
 186             }
 187         }
 188     )*}
 189 }
 190
 191 // only negative bounds
 192 macro_rules! try_from_lower_bounded {
 193     ($source:ty, $($target:ty),*) => {$(
 194         #[stable(feature = "try_from", since = "1.34.0")]
 195         #[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
 196         impl const TryFrom<$source> for $target {
 197             type Error = TryFromIntError;
 198
 199             /// Try to create the target number type from a source
 200             /// number type. This returns an error if the source value
 201             /// is outside of the range of the target type.
 202             #[inline]
 203             fn try_from(u: $source) -> Result<Self, Self::Error> {
 204                 if u >= 0 {
 205                     Ok(u as Self)
 206                 } else {
 207                     Err(TryFromIntError(()))
 208                 }
 209             }
 210         }
 211     )*}
 212 }
 213
 214 // unsigned to signed (only positive bound)
 215 macro_rules! try_from_upper_bounded {
 216     ($source:ty, $($target:ty),*) => {$(
 217         #[stable(feature = "try_from", since = "1.34.0")]
 218         #[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
 219         impl const TryFrom<$source> for $target {
 220             type Error = TryFromIntError;
 221
 222             /// Try to create the target number type from a source
 223             /// number type. This returns an error if the source value
 224             /// is outside of the range of the target type.
 225             #[inline]
 226             fn try_from(u: $source) -> Result<Self, Self::Error> {
 227                 if u > (Self::MAX as $source) {
 228                     Err(TryFromIntError(()))
 229                 } else {
 230                     Ok(u as Self)
 231                 }
 232             }
 233         }
 234     )*}
 235 }
 236
 237 // all other cases
 238 macro_rules! try_from_both_bounded {
 239     ($source:ty, $($target:ty),*) => {$(
 240         #[stable(feature = "try_from", since = "1.34.0")]
 241         #[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
 242         impl const TryFrom<$source> for $target {
 243             type Error = TryFromIntError;
 244
 245             /// Try to create the target number type from a source
 246             /// number type. This returns an error if the source value
 247             /// is outside of the range of the target type.
 248             #[inline]
 249             fn try_from(u: $source) -> Result<Self, Self::Error> {
 250                 let min = Self::MIN as $source;
 251                 let max = Self::MAX as $source;
 252                 if u < min || u > max {
 253                     Err(TryFromIntError(()))
 254                 } else {
 255                     Ok(u as Self)
 256                 }
 257             }
 258         }
 259     )*}
 260 }
 261
 262 macro_rules! rev {
 263     ($mac:ident, $source:ty, $($target:ty),*) => {$(
 264         $mac!($target, $source);
 265     )*}
 266 }
 267
 268 // intra-sign conversions
 269 try_from_upper_bounded!(u16, u8);
 270 try_from_upper_bounded!(u32, u16, u8);
 271 try_from_upper_bounded!(u64, u32, u16, u8);
 272 try_from_upper_bounded!(u128, u64, u32, u16, u8);
 273
 274 try_from_both_bounded!(i16, i8);
 275 try_from_both_bounded!(i32, i16, i8);
 276 try_from_both_bounded!(i64, i32, i16, i8);
 277 try_from_both_bounded!(i128, i64, i32, i16, i8);
 278
 279 // unsigned-to-signed
 280 try_from_upper_bounded!(u8, i8);
 281 try_from_upper_bounded!(u16, i8, i16);
 282 try_from_upper_bounded!(u32, i8, i16, i32);
 283 try_from_upper_bounded!(u64, i8, i16, i32, i64);
 284 try_from_upper_bounded!(u128, i8, i16, i32, i64, i128);
 285
 286 // signed-to-unsigned
 287 try_from_lower_bounded!(i8, u8, u16, u32, u64, u128);
 288 try_from_lower_bounded!(i16, u16, u32, u64, u128);
 289 try_from_lower_bounded!(i32, u32, u64, u128);
 290 try_from_lower_bounded!(i64, u64, u128);
 291 try_from_lower_bounded!(i128, u128);
 292 try_from_both_bounded!(i16, u8);
 293 try_from_both_bounded!(i32, u16, u8);
 294 try_from_both_bounded!(i64, u32, u16, u8);
 295 try_from_both_bounded!(i128, u64, u32, u16, u8);
 296
 297 // usize/isize
 298 try_from_upper_bounded!(usize, isize);
 299 try_from_lower_bounded!(isize, usize);
 300
 301 #[cfg(target_pointer_width = "16")]
 302 mod ptr_try_from_impls {
 303     use super::TryFromIntError;
 304     use crate::convert::TryFrom;
 305
 306     try_from_upper_bounded!(usize, u8);
 307     try_from_unbounded!(usize, u16, u32, u64, u128);
 308     try_from_upper_bounded!(usize, i8, i16);
 309     try_from_unbounded!(usize, i32, i64, i128);
 310
 311     try_from_both_bounded!(isize, u8);
 312     try_from_lower_bounded!(isize, u16, u32, u64, u128);
 313     try_from_both_bounded!(isize, i8);
 314     try_from_unbounded!(isize, i16, i32, i64, i128);
 315
 316     rev!(try_from_upper_bounded, usize, u32, u64, u128);
 317     rev!(try_from_lower_bounded, usize, i8, i16);
 318     rev!(try_from_both_bounded, usize, i32, i64, i128);
 319
 320     rev!(try_from_upper_bounded, isize, u16, u32, u64, u128);
 321     rev!(try_from_both_bounded, isize, i32, i64, i128);
 322 }
 323
 324 #[cfg(target_pointer_width = "32")]
 325 mod ptr_try_from_impls {
 326     use super::TryFromIntError;
 327     use crate::convert::TryFrom;
 328
 329     try_from_upper_bounded!(usize, u8, u16);
 330     try_from_unbounded!(usize, u32, u64, u128);
 331     try_from_upper_bounded!(usize, i8, i16, i32);
 332     try_from_unbounded!(usize, i64, i128);
 333
 334     try_from_both_bounded!(isize, u8, u16);
 335     try_from_lower_bounded!(isize, u32, u64, u128);
 336     try_from_both_bounded!(isize, i8, i16);
 337     try_from_unbounded!(isize, i32, i64, i128);
 338
 339     rev!(try_from_unbounded, usize, u32);
 340     rev!(try_from_upper_bounded, usize, u64, u128);
 341     rev!(try_from_lower_bounded, usize, i8, i16, i32);
 342     rev!(try_from_both_bounded, usize, i64, i128);
 343
 344     rev!(try_from_unbounded, isize, u16);
 345     rev!(try_from_upper_bounded, isize, u32, u64, u128);
 346     rev!(try_from_unbounded, isize, i32);
 347     rev!(try_from_both_bounded, isize, i64, i128);
 348 }
 349
 350 #[cfg(target_pointer_width = "64")]
 351 mod ptr_try_from_impls {
 352     use super::TryFromIntError;
 353     use crate::convert::TryFrom;
 354
 355     try_from_upper_bounded!(usize, u8, u16, u32);
 356     try_from_unbounded!(usize, u64, u128);
 357     try_from_upper_bounded!(usize, i8, i16, i32, i64);
 358     try_from_unbounded!(usize, i128);
 359
 360     try_from_both_bounded!(isize, u8, u16, u32);
 361     try_from_lower_bounded!(isize, u64, u128);
 362     try_from_both_bounded!(isize, i8, i16, i32);
 363     try_from_unbounded!(isize, i64, i128);
 364
 365     rev!(try_from_unbounded, usize, u32, u64);
 366     rev!(try_from_upper_bounded, usize, u128);
 367     rev!(try_from_lower_bounded, usize, i8, i16, i32, i64);
 368     rev!(try_from_both_bounded, usize, i128);
 369
 370     rev!(try_from_unbounded, isize, u16, u32);
 371     rev!(try_from_upper_bounded, isize, u64, u128);
 372     rev!(try_from_unbounded, isize, i32, i64);
 373     rev!(try_from_both_bounded, isize, i128);
 374 }
 375
 376 // Conversion traits for non-zero integer types
 377 use crate::num::NonZeroI128;
 378 use crate::num::NonZeroI16;
 379 use crate::num::NonZeroI32;
 380 use crate::num::NonZeroI64;
 381 use crate::num::NonZeroI8;
 382 use crate::num::NonZeroIsize;
 383 use crate::num::NonZeroU128;
 384 use crate::num::NonZeroU16;
 385 use crate::num::NonZeroU32;
 386 use crate::num::NonZeroU64;
 387 use crate::num::NonZeroU8;
 388 use crate::num::NonZeroUsize;
 389
 390 macro_rules! nzint_impl_from {
 391     ($Small: ty, $Large: ty, #[$attr:meta], $doc: expr) => {
 392         #[$attr]
 393         #[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
 394         impl const From<$Small> for $Large {
 395             // Rustdocs on the impl block show a "[+] show undocumented items" toggle.
 396             // Rustdocs on functions do not.
 397             #[doc = $doc]
 398             #[inline]
 399             fn from(small: $Small) -> Self {
 400                 // SAFETY: input type guarantees the value is non-zero
 401                 unsafe {
 402                     Self::new_unchecked(From::from(small.get()))
 403                 }
 404             }
 405         }
 406     };
 407     ($Small: ty, $Large: ty, #[$attr:meta]) => {
 408         nzint_impl_from!($Small,
 409                    $Large,
 410                    #[$attr],
 411                    concat!("Converts `",
 412                            stringify!($Small),
 413                            "` to `",
 414                            stringify!($Large),
 415                            "` losslessly."));
 416     }
 417 }
 418
 419 // Non-zero Unsigned -> Non-zero Unsigned
 420 nzint_impl_from! { NonZeroU8, NonZeroU16, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 421 nzint_impl_from! { NonZeroU8, NonZeroU32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 422 nzint_impl_from! { NonZeroU8, NonZeroU64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 423 nzint_impl_from! { NonZeroU8, NonZeroU128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 424 nzint_impl_from! { NonZeroU8, NonZeroUsize, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 425 nzint_impl_from! { NonZeroU16, NonZeroU32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 426 nzint_impl_from! { NonZeroU16, NonZeroU64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 427 nzint_impl_from! { NonZeroU16, NonZeroU128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 428 nzint_impl_from! { NonZeroU16, NonZeroUsize, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 429 nzint_impl_from! { NonZeroU32, NonZeroU64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 430 nzint_impl_from! { NonZeroU32, NonZeroU128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 431 nzint_impl_from! { NonZeroU64, NonZeroU128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 432
 433 // Non-zero Signed -> Non-zero Signed
 434 nzint_impl_from! { NonZeroI8, NonZeroI16, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 435 nzint_impl_from! { NonZeroI8, NonZeroI32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 436 nzint_impl_from! { NonZeroI8, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 437 nzint_impl_from! { NonZeroI8, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 438 nzint_impl_from! { NonZeroI8, NonZeroIsize, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 439 nzint_impl_from! { NonZeroI16, NonZeroI32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 440 nzint_impl_from! { NonZeroI16, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 441 nzint_impl_from! { NonZeroI16, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 442 nzint_impl_from! { NonZeroI16, NonZeroIsize, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 443 nzint_impl_from! { NonZeroI32, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 444 nzint_impl_from! { NonZeroI32, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 445 nzint_impl_from! { NonZeroI64, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 446
 447 // NonZero UnSigned -> Non-zero Signed
 448 nzint_impl_from! { NonZeroU8, NonZeroI16, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 449 nzint_impl_from! { NonZeroU8, NonZeroI32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 450 nzint_impl_from! { NonZeroU8, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 451 nzint_impl_from! { NonZeroU8, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 452 nzint_impl_from! { NonZeroU8, NonZeroIsize, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 453 nzint_impl_from! { NonZeroU16, NonZeroI32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 454 nzint_impl_from! { NonZeroU16, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 455 nzint_impl_from! { NonZeroU16, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 456 nzint_impl_from! { NonZeroU32, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 457 nzint_impl_from! { NonZeroU32, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 458 nzint_impl_from! { NonZeroU64, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 459
 460 macro_rules! nzint_impl_try_from_int {
 461     ($Int: ty, $NonZeroInt: ty, #[$attr:meta], $doc: expr) => {
 462         #[$attr]
 463         impl TryFrom<$Int> for $NonZeroInt {
 464             type Error = TryFromIntError;
 465
 466             // Rustdocs on the impl block show a "[+] show undocumented items" toggle.
 467             // Rustdocs on functions do not.
 468             #[doc = $doc]
 469             #[inline]
 470             fn try_from(value: $Int) -> Result<Self, Self::Error> {
 471                 Self::new(value).ok_or(TryFromIntError(()))
 472             }
 473         }
 474     };
 475     ($Int: ty, $NonZeroInt: ty, #[$attr:meta]) => {
 476         nzint_impl_try_from_int!($Int,
 477                                  $NonZeroInt,
 478                                  #[$attr],
 479                                  concat!("Attempts to convert `",
 480                                          stringify!($Int),
 481                                          "` to `",
 482                                          stringify!($NonZeroInt),
 483                                          "`."));
 484     }
 485 }
 486
 487 // Int -> Non-zero Int
 488 nzint_impl_try_from_int! { u8, NonZeroU8, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 489 nzint_impl_try_from_int! { u16, NonZeroU16, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 490 nzint_impl_try_from_int! { u32, NonZeroU32, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 491 nzint_impl_try_from_int! { u64, NonZeroU64, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 492 nzint_impl_try_from_int! { u128, NonZeroU128, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 493 nzint_impl_try_from_int! { usize, NonZeroUsize, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 494 nzint_impl_try_from_int! { i8, NonZeroI8, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 495 nzint_impl_try_from_int! { i16, NonZeroI16, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 496 nzint_impl_try_from_int! { i32, NonZeroI32, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 497 nzint_impl_try_from_int! { i64, NonZeroI64, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 498 nzint_impl_try_from_int! { i128, NonZeroI128, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 499 nzint_impl_try_from_int! { isize, NonZeroIsize, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 500
 501 macro_rules! nzint_impl_try_from_nzint {
 502     ($From:ty => $To:ty, $doc: expr) => {
 503         #[stable(feature = "nzint_try_from_nzint_conv", since = "1.49.0")]
 504         impl TryFrom<$From> for $To {
 505             type Error = TryFromIntError;
 506
 507             // Rustdocs on the impl block show a "[+] show undocumented items" toggle.
 508             // Rustdocs on functions do not.
 509             #[doc = $doc]
 510             #[inline]
 511             fn try_from(value: $From) -> Result<Self, Self::Error> {
 512                 TryFrom::try_from(value.get()).map(|v| {
 513                     // SAFETY: $From is a NonZero type, so v is not zero.
 514                     unsafe { Self::new_unchecked(v) }
 515                 })
 516             }
 517         }
 518     };
 519     ($To:ty: $($From: ty),*) => {$(
 520         nzint_impl_try_from_nzint!(
 521             $From => $To,
 522             concat!(
 523                 "Attempts to convert `",
 524                 stringify!($From),
 525                 "` to `",
 526                 stringify!($To),
 527                 "`.",
 528             )
 529         );
 530     )*};
 531 }
 532
 533 // Non-zero int -> non-zero unsigned int
 534 nzint_impl_try_from_nzint! { NonZeroU8: NonZeroI8, NonZeroU16, NonZeroI16, NonZeroU32, NonZeroI32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroUsize, NonZeroIsize }
 535 nzint_impl_try_from_nzint! { NonZeroU16: NonZeroI8, NonZeroI16, NonZeroU32, NonZeroI32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroUsize, NonZeroIsize }
 536 nzint_impl_try_from_nzint! { NonZeroU32: NonZeroI8, NonZeroI16, NonZeroI32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroUsize, NonZeroIsize }
 537 nzint_impl_try_from_nzint! { NonZeroU64: NonZeroI8, NonZeroI16, NonZeroI32, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroUsize, NonZeroIsize }
 538 nzint_impl_try_from_nzint! { NonZeroU128: NonZeroI8, NonZeroI16, NonZeroI32, NonZeroI64, NonZeroI128, NonZeroUsize, NonZeroIsize }
 539 nzint_impl_try_from_nzint! { NonZeroUsize: NonZeroI8, NonZeroI16, NonZeroU32, NonZeroI32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroIsize }
 540
 541 // Non-zero int -> non-zero signed int
 542 nzint_impl_try_from_nzint! { NonZeroI8: NonZeroU8, NonZeroU16, NonZeroI16, NonZeroU32, NonZeroI32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroUsize, NonZeroIsize }
 543 nzint_impl_try_from_nzint! { NonZeroI16: NonZeroU16, NonZeroU32, NonZeroI32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroUsize, NonZeroIsize }
 544 nzint_impl_try_from_nzint! { NonZeroI32: NonZeroU32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroUsize, NonZeroIsize }
 545 nzint_impl_try_from_nzint! { NonZeroI64: NonZeroU64, NonZeroU128, NonZeroI128, NonZeroUsize, NonZeroIsize }
 546 nzint_impl_try_from_nzint! { NonZeroI128: NonZeroU128, NonZeroUsize, NonZeroIsize }
 547 nzint_impl_try_from_nzint! { NonZeroIsize: NonZeroU16, NonZeroU32, NonZeroI32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroUsize }