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                 #[inline]
  29                 unsafe fn to_int_unchecked(self) -> $Int {
  30                     // SAFETY: the safety contract must be upheld by the caller.
  31                     unsafe { crate::intrinsics::float_to_int_unchecked(self) }
  32                 }
  33             }
  34         )+
  35     }
  36 }
  37
  38 impl_float_to_int!(f32 => u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize);
  39 impl_float_to_int!(f64 => u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize);
  40
  41 // Conversion traits for primitive integer and float types
  42 // Conversions T -> T are covered by a blanket impl and therefore excluded
  43 // Some conversions from and to usize/isize are not implemented due to portability concerns
  44 macro_rules! impl_from {
  45     ($Small: ty, $Large: ty, #[$attr:meta], $doc: expr) => {
  46         #[$attr]
  47         #[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
  48         impl const From<$Small> for $Large {
  49             // Rustdocs on the impl block show a "[+] show undocumented items" toggle.
  50             // Rustdocs on functions do not.
  51             #[doc = $doc]
  52             #[inline(always)]
  53             fn from(small: $Small) -> Self {
  54                 small as Self
  55             }
  56         }
  57     };
  58     ($Small: ty, $Large: ty, #[$attr:meta]) => {
  59         impl_from!($Small,
  60                    $Large,
  61                    #[$attr],
  62                    concat!("Converts `",
  63                            stringify!($Small),
  64                            "` to `",
  65                            stringify!($Large),
  66                            "` losslessly."));
  67     }
  68 }
  69
  70 macro_rules! impl_from_bool {
  71     ($target: ty, #[$attr:meta]) => {
  72         impl_from!(bool, $target, #[$attr], concat!("Converts a `bool` to a `",
  73             stringify!($target), "`. The resulting value is `0` for `false` and `1` for `true`
  74 values.
  75
  76 # Examples
  77
  78 ```
  79 assert_eq!(", stringify!($target), "::from(true), 1);
  80 assert_eq!(", stringify!($target), "::from(false), 0);
  81 ```"));
  82     };
  83 }
  84
  85 // Bool -> Any
  86 impl_from_bool! { u8, #[stable(feature = "from_bool", since = "1.28.0")] }
  87 impl_from_bool! { u16, #[stable(feature = "from_bool", since = "1.28.0")] }
  88 impl_from_bool! { u32, #[stable(feature = "from_bool", since = "1.28.0")] }
  89 impl_from_bool! { u64, #[stable(feature = "from_bool", since = "1.28.0")] }
  90 impl_from_bool! { u128, #[stable(feature = "from_bool", since = "1.28.0")] }
  91 impl_from_bool! { usize, #[stable(feature = "from_bool", since = "1.28.0")] }
  92 impl_from_bool! { i8, #[stable(feature = "from_bool", since = "1.28.0")] }
  93 impl_from_bool! { i16, #[stable(feature = "from_bool", since = "1.28.0")] }
  94 impl_from_bool! { i32, #[stable(feature = "from_bool", since = "1.28.0")] }
  95 impl_from_bool! { i64, #[stable(feature = "from_bool", since = "1.28.0")] }
  96 impl_from_bool! { i128, #[stable(feature = "from_bool", since = "1.28.0")] }
  97 impl_from_bool! { isize, #[stable(feature = "from_bool", since = "1.28.0")] }
  98
  99 // Unsigned -> Unsigned
 100 impl_from! { u8, u16, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 101 impl_from! { u8, u32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 102 impl_from! { u8, u64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 103 impl_from! { u8, u128, #[stable(feature = "i128", since = "1.26.0")] }
 104 impl_from! { u8, usize, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 105 impl_from! { u16, u32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 106 impl_from! { u16, u64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 107 impl_from! { u16, u128, #[stable(feature = "i128", since = "1.26.0")] }
 108 impl_from! { u32, u64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 109 impl_from! { u32, u128, #[stable(feature = "i128", since = "1.26.0")] }
 110 impl_from! { u64, u128, #[stable(feature = "i128", since = "1.26.0")] }
 111
 112 // Signed -> Signed
 113 impl_from! { i8, i16, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 114 impl_from! { i8, i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 115 impl_from! { i8, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 116 impl_from! { i8, i128, #[stable(feature = "i128", since = "1.26.0")] }
 117 impl_from! { i8, isize, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 118 impl_from! { i16, i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 119 impl_from! { i16, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 120 impl_from! { i16, i128, #[stable(feature = "i128", since = "1.26.0")] }
 121 impl_from! { i32, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 122 impl_from! { i32, i128, #[stable(feature = "i128", since = "1.26.0")] }
 123 impl_from! { i64, i128, #[stable(feature = "i128", since = "1.26.0")] }
 124
 125 // Unsigned -> Signed
 126 impl_from! { u8, i16, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 127 impl_from! { u8, i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 128 impl_from! { u8, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 129 impl_from! { u8, i128, #[stable(feature = "i128", since = "1.26.0")] }
 130 impl_from! { u16, i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 131 impl_from! { u16, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 132 impl_from! { u16, i128, #[stable(feature = "i128", since = "1.26.0")] }
 133 impl_from! { u32, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
 134 impl_from! { u32, i128, #[stable(feature = "i128", since = "1.26.0")] }
 135 impl_from! { u64, i128, #[stable(feature = "i128", since = "1.26.0")] }
 136
 137 // The C99 standard defines bounds on INTPTR_MIN, INTPTR_MAX, and UINTPTR_MAX
 138 // which imply that pointer-sized integers must be at least 16 bits:
 139 // https://port70.net/~nsz/c/c99/n1256.html#7.18.2.4
 140 impl_from! { u16, usize, #[stable(feature = "lossless_iusize_conv", since = "1.26.0")] }
 141 impl_from! { u8, isize, #[stable(feature = "lossless_iusize_conv", since = "1.26.0")] }
 142 impl_from! { i16, isize, #[stable(feature = "lossless_iusize_conv", since = "1.26.0")] }
 143
 144 // RISC-V defines the possibility of a 128-bit address space (RV128).
 145
 146 // CHERI proposes 256-bit “capabilities”. Unclear if this would be relevant to usize/isize.
 147 // https://www.cl.cam.ac.uk/research/security/ctsrd/pdfs/20171017a-cheri-poster.pdf
 148 // https://www.csl.sri.com/users/neumann/2012resolve-cheri.pdf
 149
 150 // Note: integers can only be represented with full precision in a float if
 151 // they fit in the significand, which is 24 bits in f32 and 53 bits in f64.
 152 // Lossy float conversions are not implemented at this time.
 153
 154 // Signed -> Float
 155 impl_from! { i8, f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 156 impl_from! { i8, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 157 impl_from! { i16, f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 158 impl_from! { i16, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 159 impl_from! { i32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 160
 161 // Unsigned -> Float
 162 impl_from! { u8, f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 163 impl_from! { u8, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 164 impl_from! { u16, f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 165 impl_from! { u16, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 166 impl_from! { u32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 167
 168 // Float -> Float
 169 impl_from! { f32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
 170
 171 // bool -> Float
 172 #[stable(feature = "float_from_bool", since = "CURRENT_RUSTC_VERSION")]
 173 #[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
 174 impl const From<bool> for f32 {
 175     /// Converts `bool` to `f32` losslessly.
 176     #[inline]
 177     fn from(small: bool) -> Self {
 178         small as u8 as Self
 179     }
 180 }
 181 #[stable(feature = "float_from_bool", since = "CURRENT_RUSTC_VERSION")]
 182 #[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
 183 impl const From<bool> for f64 {
 184     /// Converts `bool` to `f64` losslessly.
 185     #[inline]
 186     fn from(small: bool) -> Self {
 187         small as u8 as Self
 188     }
 189 }
 190
 191 // no possible bounds violation
 192 macro_rules! try_from_unbounded {
 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(value: $source) -> Result<Self, Self::Error> {
 204                 Ok(value as Self)
 205             }
 206         }
 207     )*}
 208 }
 209
 210 // only negative bounds
 211 macro_rules! try_from_lower_bounded {
 212     ($source:ty, $($target:ty),*) => {$(
 213         #[stable(feature = "try_from", since = "1.34.0")]
 214         #[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
 215         impl const TryFrom<$source> for $target {
 216             type Error = TryFromIntError;
 217
 218             /// Try to create the target number type from a source
 219             /// number type. This returns an error if the source value
 220             /// is outside of the range of the target type.
 221             #[inline]
 222             fn try_from(u: $source) -> Result<Self, Self::Error> {
 223                 if u >= 0 {
 224                     Ok(u as Self)
 225                 } else {
 226                     Err(TryFromIntError(()))
 227                 }
 228             }
 229         }
 230     )*}
 231 }
 232
 233 // unsigned to signed (only positive bound)
 234 macro_rules! try_from_upper_bounded {
 235     ($source:ty, $($target:ty),*) => {$(
 236         #[stable(feature = "try_from", since = "1.34.0")]
 237         #[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
 238         impl const TryFrom<$source> for $target {
 239             type Error = TryFromIntError;
 240
 241             /// Try to create the target number type from a source
 242             /// number type. This returns an error if the source value
 243             /// is outside of the range of the target type.
 244             #[inline]
 245             fn try_from(u: $source) -> Result<Self, Self::Error> {
 246                 if u > (Self::MAX as $source) {
 247                     Err(TryFromIntError(()))
 248                 } else {
 249                     Ok(u as Self)
 250                 }
 251             }
 252         }
 253     )*}
 254 }
 255
 256 // all other cases
 257 macro_rules! try_from_both_bounded {
 258     ($source:ty, $($target:ty),*) => {$(
 259         #[stable(feature = "try_from", since = "1.34.0")]
 260         #[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
 261         impl const TryFrom<$source> for $target {
 262             type Error = TryFromIntError;
 263
 264             /// Try to create the target number type from a source
 265             /// number type. This returns an error if the source value
 266             /// is outside of the range of the target type.
 267             #[inline]
 268             fn try_from(u: $source) -> Result<Self, Self::Error> {
 269                 let min = Self::MIN as $source;
 270                 let max = Self::MAX as $source;
 271                 if u < min || u > max {
 272                     Err(TryFromIntError(()))
 273                 } else {
 274                     Ok(u as Self)
 275                 }
 276             }
 277         }
 278     )*}
 279 }
 280
 281 macro_rules! rev {
 282     ($mac:ident, $source:ty, $($target:ty),*) => {$(
 283         $mac!($target, $source);
 284     )*}
 285 }
 286
 287 // intra-sign conversions
 288 try_from_upper_bounded!(u16, u8);
 289 try_from_upper_bounded!(u32, u16, u8);
 290 try_from_upper_bounded!(u64, u32, u16, u8);
 291 try_from_upper_bounded!(u128, u64, u32, u16, u8);
 292
 293 try_from_both_bounded!(i16, i8);
 294 try_from_both_bounded!(i32, i16, i8);
 295 try_from_both_bounded!(i64, i32, i16, i8);
 296 try_from_both_bounded!(i128, i64, i32, i16, i8);
 297
 298 // unsigned-to-signed
 299 try_from_upper_bounded!(u8, i8);
 300 try_from_upper_bounded!(u16, i8, i16);
 301 try_from_upper_bounded!(u32, i8, i16, i32);
 302 try_from_upper_bounded!(u64, i8, i16, i32, i64);
 303 try_from_upper_bounded!(u128, i8, i16, i32, i64, i128);
 304
 305 // signed-to-unsigned
 306 try_from_lower_bounded!(i8, u8, u16, u32, u64, u128);
 307 try_from_lower_bounded!(i16, u16, u32, u64, u128);
 308 try_from_lower_bounded!(i32, u32, u64, u128);
 309 try_from_lower_bounded!(i64, u64, u128);
 310 try_from_lower_bounded!(i128, u128);
 311 try_from_both_bounded!(i16, u8);
 312 try_from_both_bounded!(i32, u16, u8);
 313 try_from_both_bounded!(i64, u32, u16, u8);
 314 try_from_both_bounded!(i128, u64, u32, u16, u8);
 315
 316 // usize/isize
 317 try_from_upper_bounded!(usize, isize);
 318 try_from_lower_bounded!(isize, usize);
 319
 320 #[cfg(target_pointer_width = "16")]
 321 mod ptr_try_from_impls {
 322     use super::TryFromIntError;
 323     use crate::convert::TryFrom;
 324
 325     try_from_upper_bounded!(usize, u8);
 326     try_from_unbounded!(usize, u16, u32, u64, u128);
 327     try_from_upper_bounded!(usize, i8, i16);
 328     try_from_unbounded!(usize, i32, i64, i128);
 329
 330     try_from_both_bounded!(isize, u8);
 331     try_from_lower_bounded!(isize, u16, u32, u64, u128);
 332     try_from_both_bounded!(isize, i8);
 333     try_from_unbounded!(isize, i16, i32, i64, i128);
 334
 335     rev!(try_from_upper_bounded, usize, u32, u64, u128);
 336     rev!(try_from_lower_bounded, usize, i8, i16);
 337     rev!(try_from_both_bounded, usize, i32, i64, i128);
 338
 339     rev!(try_from_upper_bounded, isize, u16, u32, u64, u128);
 340     rev!(try_from_both_bounded, isize, i32, i64, i128);
 341 }
 342
 343 #[cfg(target_pointer_width = "32")]
 344 mod ptr_try_from_impls {
 345     use super::TryFromIntError;
 346     use crate::convert::TryFrom;
 347
 348     try_from_upper_bounded!(usize, u8, u16);
 349     try_from_unbounded!(usize, u32, u64, u128);
 350     try_from_upper_bounded!(usize, i8, i16, i32);
 351     try_from_unbounded!(usize, i64, i128);
 352
 353     try_from_both_bounded!(isize, u8, u16);
 354     try_from_lower_bounded!(isize, u32, u64, u128);
 355     try_from_both_bounded!(isize, i8, i16);
 356     try_from_unbounded!(isize, i32, i64, i128);
 357
 358     rev!(try_from_unbounded, usize, u32);
 359     rev!(try_from_upper_bounded, usize, u64, u128);
 360     rev!(try_from_lower_bounded, usize, i8, i16, i32);
 361     rev!(try_from_both_bounded, usize, i64, i128);
 362
 363     rev!(try_from_unbounded, isize, u16);
 364     rev!(try_from_upper_bounded, isize, u32, u64, u128);
 365     rev!(try_from_unbounded, isize, i32);
 366     rev!(try_from_both_bounded, isize, i64, i128);
 367 }
 368
 369 #[cfg(target_pointer_width = "64")]
 370 mod ptr_try_from_impls {
 371     use super::TryFromIntError;
 372     use crate::convert::TryFrom;
 373
 374     try_from_upper_bounded!(usize, u8, u16, u32);
 375     try_from_unbounded!(usize, u64, u128);
 376     try_from_upper_bounded!(usize, i8, i16, i32, i64);
 377     try_from_unbounded!(usize, i128);
 378
 379     try_from_both_bounded!(isize, u8, u16, u32);
 380     try_from_lower_bounded!(isize, u64, u128);
 381     try_from_both_bounded!(isize, i8, i16, i32);
 382     try_from_unbounded!(isize, i64, i128);
 383
 384     rev!(try_from_unbounded, usize, u32, u64);
 385     rev!(try_from_upper_bounded, usize, u128);
 386     rev!(try_from_lower_bounded, usize, i8, i16, i32, i64);
 387     rev!(try_from_both_bounded, usize, i128);
 388
 389     rev!(try_from_unbounded, isize, u16, u32);
 390     rev!(try_from_upper_bounded, isize, u64, u128);
 391     rev!(try_from_unbounded, isize, i32, i64);
 392     rev!(try_from_both_bounded, isize, i128);
 393 }
 394
 395 // Conversion traits for non-zero integer types
 396 use crate::num::NonZeroI128;
 397 use crate::num::NonZeroI16;
 398 use crate::num::NonZeroI32;
 399 use crate::num::NonZeroI64;
 400 use crate::num::NonZeroI8;
 401 use crate::num::NonZeroIsize;
 402 use crate::num::NonZeroU128;
 403 use crate::num::NonZeroU16;
 404 use crate::num::NonZeroU32;
 405 use crate::num::NonZeroU64;
 406 use crate::num::NonZeroU8;
 407 use crate::num::NonZeroUsize;
 408
 409 macro_rules! nzint_impl_from {
 410     ($Small: ty, $Large: ty, #[$attr:meta], $doc: expr) => {
 411         #[$attr]
 412         #[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
 413         impl const From<$Small> for $Large {
 414             // Rustdocs on the impl block show a "[+] show undocumented items" toggle.
 415             // Rustdocs on functions do not.
 416             #[doc = $doc]
 417             #[inline]
 418             fn from(small: $Small) -> Self {
 419                 // SAFETY: input type guarantees the value is non-zero
 420                 unsafe {
 421                     Self::new_unchecked(From::from(small.get()))
 422                 }
 423             }
 424         }
 425     };
 426     ($Small: ty, $Large: ty, #[$attr:meta]) => {
 427         nzint_impl_from!($Small,
 428                    $Large,
 429                    #[$attr],
 430                    concat!("Converts `",
 431                            stringify!($Small),
 432                            "` to `",
 433                            stringify!($Large),
 434                            "` losslessly."));
 435     }
 436 }
 437
 438 // Non-zero Unsigned -> Non-zero Unsigned
 439 nzint_impl_from! { NonZeroU8, NonZeroU16, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 440 nzint_impl_from! { NonZeroU8, NonZeroU32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 441 nzint_impl_from! { NonZeroU8, NonZeroU64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 442 nzint_impl_from! { NonZeroU8, NonZeroU128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 443 nzint_impl_from! { NonZeroU8, NonZeroUsize, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 444 nzint_impl_from! { NonZeroU16, NonZeroU32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 445 nzint_impl_from! { NonZeroU16, NonZeroU64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 446 nzint_impl_from! { NonZeroU16, NonZeroU128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 447 nzint_impl_from! { NonZeroU16, NonZeroUsize, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 448 nzint_impl_from! { NonZeroU32, NonZeroU64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 449 nzint_impl_from! { NonZeroU32, NonZeroU128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 450 nzint_impl_from! { NonZeroU64, NonZeroU128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 451
 452 // Non-zero Signed -> Non-zero Signed
 453 nzint_impl_from! { NonZeroI8, NonZeroI16, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 454 nzint_impl_from! { NonZeroI8, NonZeroI32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 455 nzint_impl_from! { NonZeroI8, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 456 nzint_impl_from! { NonZeroI8, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 457 nzint_impl_from! { NonZeroI8, NonZeroIsize, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 458 nzint_impl_from! { NonZeroI16, NonZeroI32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 459 nzint_impl_from! { NonZeroI16, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 460 nzint_impl_from! { NonZeroI16, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 461 nzint_impl_from! { NonZeroI16, NonZeroIsize, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 462 nzint_impl_from! { NonZeroI32, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 463 nzint_impl_from! { NonZeroI32, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 464 nzint_impl_from! { NonZeroI64, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 465
 466 // NonZero UnSigned -> Non-zero Signed
 467 nzint_impl_from! { NonZeroU8, NonZeroI16, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 468 nzint_impl_from! { NonZeroU8, NonZeroI32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 469 nzint_impl_from! { NonZeroU8, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 470 nzint_impl_from! { NonZeroU8, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 471 nzint_impl_from! { NonZeroU8, NonZeroIsize, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 472 nzint_impl_from! { NonZeroU16, NonZeroI32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 473 nzint_impl_from! { NonZeroU16, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 474 nzint_impl_from! { NonZeroU16, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 475 nzint_impl_from! { NonZeroU32, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 476 nzint_impl_from! { NonZeroU32, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 477 nzint_impl_from! { NonZeroU64, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
 478
 479 macro_rules! nzint_impl_try_from_int {
 480     ($Int: ty, $NonZeroInt: ty, #[$attr:meta], $doc: expr) => {
 481         #[$attr]
 482         impl TryFrom<$Int> for $NonZeroInt {
 483             type Error = TryFromIntError;
 484
 485             // Rustdocs on the impl block show a "[+] show undocumented items" toggle.
 486             // Rustdocs on functions do not.
 487             #[doc = $doc]
 488             #[inline]
 489             fn try_from(value: $Int) -> Result<Self, Self::Error> {
 490                 Self::new(value).ok_or(TryFromIntError(()))
 491             }
 492         }
 493     };
 494     ($Int: ty, $NonZeroInt: ty, #[$attr:meta]) => {
 495         nzint_impl_try_from_int!($Int,
 496                                  $NonZeroInt,
 497                                  #[$attr],
 498                                  concat!("Attempts to convert `",
 499                                          stringify!($Int),
 500                                          "` to `",
 501                                          stringify!($NonZeroInt),
 502                                          "`."));
 503     }
 504 }
 505
 506 // Int -> Non-zero Int
 507 nzint_impl_try_from_int! { u8, NonZeroU8, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 508 nzint_impl_try_from_int! { u16, NonZeroU16, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 509 nzint_impl_try_from_int! { u32, NonZeroU32, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 510 nzint_impl_try_from_int! { u64, NonZeroU64, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 511 nzint_impl_try_from_int! { u128, NonZeroU128, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 512 nzint_impl_try_from_int! { usize, NonZeroUsize, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 513 nzint_impl_try_from_int! { i8, NonZeroI8, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 514 nzint_impl_try_from_int! { i16, NonZeroI16, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 515 nzint_impl_try_from_int! { i32, NonZeroI32, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 516 nzint_impl_try_from_int! { i64, NonZeroI64, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 517 nzint_impl_try_from_int! { i128, NonZeroI128, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 518 nzint_impl_try_from_int! { isize, NonZeroIsize, #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")] }
 519
 520 macro_rules! nzint_impl_try_from_nzint {
 521     ($From:ty => $To:ty, $doc: expr) => {
 522         #[stable(feature = "nzint_try_from_nzint_conv", since = "1.49.0")]
 523         impl TryFrom<$From> for $To {
 524             type Error = TryFromIntError;
 525
 526             // Rustdocs on the impl block show a "[+] show undocumented items" toggle.
 527             // Rustdocs on functions do not.
 528             #[doc = $doc]
 529             #[inline]
 530             fn try_from(value: $From) -> Result<Self, Self::Error> {
 531                 TryFrom::try_from(value.get()).map(|v| {
 532                     // SAFETY: $From is a NonZero type, so v is not zero.
 533                     unsafe { Self::new_unchecked(v) }
 534                 })
 535             }
 536         }
 537     };
 538     ($To:ty: $($From: ty),*) => {$(
 539         nzint_impl_try_from_nzint!(
 540             $From => $To,
 541             concat!(
 542                 "Attempts to convert `",
 543                 stringify!($From),
 544                 "` to `",
 545                 stringify!($To),
 546                 "`.",
 547             )
 548         );
 549     )*};
 550 }
 551
 552 // Non-zero int -> non-zero unsigned int
 553 nzint_impl_try_from_nzint! { NonZeroU8: NonZeroI8, NonZeroU16, NonZeroI16, NonZeroU32, NonZeroI32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroUsize, NonZeroIsize }
 554 nzint_impl_try_from_nzint! { NonZeroU16: NonZeroI8, NonZeroI16, NonZeroU32, NonZeroI32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroUsize, NonZeroIsize }
 555 nzint_impl_try_from_nzint! { NonZeroU32: NonZeroI8, NonZeroI16, NonZeroI32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroUsize, NonZeroIsize }
 556 nzint_impl_try_from_nzint! { NonZeroU64: NonZeroI8, NonZeroI16, NonZeroI32, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroUsize, NonZeroIsize }
 557 nzint_impl_try_from_nzint! { NonZeroU128: NonZeroI8, NonZeroI16, NonZeroI32, NonZeroI64, NonZeroI128, NonZeroUsize, NonZeroIsize }
 558 nzint_impl_try_from_nzint! { NonZeroUsize: NonZeroI8, NonZeroI16, NonZeroU32, NonZeroI32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroIsize }
 559
 560 // Non-zero int -> non-zero signed int
 561 nzint_impl_try_from_nzint! { NonZeroI8: NonZeroU8, NonZeroU16, NonZeroI16, NonZeroU32, NonZeroI32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroUsize, NonZeroIsize }
 562 nzint_impl_try_from_nzint! { NonZeroI16: NonZeroU16, NonZeroU32, NonZeroI32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroUsize, NonZeroIsize }
 563 nzint_impl_try_from_nzint! { NonZeroI32: NonZeroU32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroUsize, NonZeroIsize }
 564 nzint_impl_try_from_nzint! { NonZeroI64: NonZeroU64, NonZeroU128, NonZeroI128, NonZeroUsize, NonZeroIsize }
 565 nzint_impl_try_from_nzint! { NonZeroI128: NonZeroU128, NonZeroUsize, NonZeroIsize }
 566 nzint_impl_try_from_nzint! { NonZeroIsize: NonZeroU16, NonZeroU32, NonZeroI32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128, NonZeroUsize }