Use generic NonZero.

compiler/rustc_abi/src/layout.rs

@@ -2,6 +2,7 @@ use std::borrow::{Borrow, Cow};
 use std::cmp;
 use std::fmt::{self, Write};
 use std::iter;
+use std::num::NonZero;
 use std::ops::Bound;
 use std::ops::Deref;
 
@@ -10,8 +11,8 @@ use tracing::debug;
 
 use crate::{
     Abi, AbiAndPrefAlign, Align, FieldsShape, IndexSlice, IndexVec, Integer, LayoutS, Niche,
-    NonZeroUsize, Primitive, ReprOptions, Scalar, Size, StructKind, TagEncoding, TargetDataLayout,
-    Variants, WrappingRange,
+    Primitive, ReprOptions, Scalar, Size, StructKind, TagEncoding, TargetDataLayout, Variants,
+    WrappingRange,
 };
 
 // A variant is absent if it's uninhabited and only has ZST fields.
@@ -327,7 +328,7 @@ pub trait LayoutCalculator {
 
         Some(LayoutS {
             variants: Variants::Single { index: VariantIdx::new(0) },
-            fields: FieldsShape::Union(NonZeroUsize::new(only_variant.len())?),
+            fields: FieldsShape::Union(NonZero::new(only_variant.len())?),
             abi,
             largest_niche: None,
             align,

compiler/rustc_abi/src/lib.rs

@@ -4,7 +4,7 @@
 #![cfg_attr(feature = "nightly", feature(rustdoc_internals))]
 
 use std::fmt;
-use std::num::{NonZeroUsize, ParseIntError};
+use std::num::{NonZero, ParseIntError};
 use std::ops::{Add, AddAssign, Mul, RangeInclusive, Sub};
 use std::str::FromStr;
 
@@ -1147,7 +1147,7 @@ pub enum FieldsShape<FieldIdx: Idx> {
     Primitive,
 
     /// All fields start at no offset. The `usize` is the field count.
-    Union(NonZeroUsize),
+    Union(NonZero<usize>),
 
     /// Array/vector-like placement, with all fields of identical types.
     Array { stride: Size, count: u64 },

compiler/rustc_ast/src/ast.rs

@@ -2164,7 +2164,7 @@ pub enum TyKind {
     MacCall(P<MacCall>),
     /// Placeholder for a `va_list`.
     CVarArgs,
-    /// Pattern types like `pattern_type!(u32 is 1..=)`, which is the same as `NonZeroU32`,
+    /// Pattern types like `pattern_type!(u32 is 1..=)`, which is the same as `NonZero<u32>`,
     /// just as part of the type system.
     Pat(P<Ty>, P<Pat>),
     /// Sometimes we need a dummy value when no error has occurred.

compiler/stable_mir/src/abi.rs

@@ -6,7 +6,7 @@ use crate::ty::{Align, IndexedVal, Ty, VariantIdx};
 use crate::Error;
 use crate::Opaque;
 use std::fmt::{self, Debug};
-use std::num::NonZeroUsize;
+use std::num::NonZero;
 use std::ops::RangeInclusive;
 
 /// A function ABI definition.
@@ -133,7 +133,7 @@ pub enum FieldsShape {
     Primitive,
 
     /// All fields start at no offset. The `usize` is the field count.
-    Union(NonZeroUsize),
+    Union(NonZero<usize>),
 
     /// Array/vector-like placement, with all fields of identical types.
     Array { stride: Size, count: u64 },

library/core/src/iter/adapters/step_by.rs

@@ -1,7 +1,7 @@
 use crate::{
     intrinsics,
     iter::{from_fn, TrustedLen, TrustedRandomAccess},
-    num::NonZeroUsize,
+    num::NonZero,
     ops::{Range, Try},
 };
 
@@ -42,10 +42,10 @@ impl<I> StepBy<I> {
     /// The `step` that was originally passed to `Iterator::step_by(step)`,
     /// aka `self.step_minus_one + 1`.
     #[inline]
-    fn original_step(&self) -> NonZeroUsize {
+    fn original_step(&self) -> NonZero<usize> {
         // SAFETY: By type invariant, `step_minus_one` cannot be `MAX`, which
         // means the addition cannot overflow and the result cannot be zero.
-        unsafe { NonZeroUsize::new_unchecked(intrinsics::unchecked_add(self.step_minus_one, 1)) }
+        unsafe { NonZero::new_unchecked(intrinsics::unchecked_add(self.step_minus_one, 1)) }
     }
 }
 
@@ -231,12 +231,12 @@ unsafe impl<I: Iterator> StepByImpl<I> for StepBy<I> {
     #[inline]
     default fn spec_size_hint(&self) -> (usize, Option<usize>) {
         #[inline]
-        fn first_size(step: NonZeroUsize) -> impl Fn(usize) -> usize {
+        fn first_size(step: NonZero<usize>) -> impl Fn(usize) -> usize {
             move |n| if n == 0 { 0 } else { 1 + (n - 1) / step }
         }
 
         #[inline]
-        fn other_size(step: NonZeroUsize) -> impl Fn(usize) -> usize {
+        fn other_size(step: NonZero<usize>) -> impl Fn(usize) -> usize {
             move |n| n / step
         }
 

src/tools/build-manifest/src/main.rs

@@ -236,7 +236,7 @@ fn main() {
     let num_threads = if let Some(num) = env::var_os("BUILD_MANIFEST_NUM_THREADS") {
         num.to_str().unwrap().parse().expect("invalid number for BUILD_MANIFEST_NUM_THREADS")
     } else {
-        std::thread::available_parallelism().map_or(1, std::num::NonZeroUsize::get)
+        std::thread::available_parallelism().map_or(1, std::num::NonZero::get)
     };
     rayon::ThreadPoolBuilder::new()
         .num_threads(num_threads)

src/tools/clippy/clippy_lints/src/transmute/eager_transmute.rs

@@ -87,7 +87,7 @@ pub(super) fn check<'tcx>(
         && is_normalizable(cx, cx.param_env, from_ty)
         && is_normalizable(cx, cx.param_env, to_ty)
         // we only want to lint if the target type has a niche that is larger than the one of the source type
-        // e.g. `u8` to `NonZeroU8` should lint, but `NonZeroU8` to `u8` should not
+        // e.g. `u8` to `NonZero<u8>` should lint, but `NonZero<u8>` to `u8` should not
         && let Ok(from_layout) = cx.tcx.layout_of(cx.param_env.and(from_ty))
         && let Ok(to_layout) = cx.tcx.layout_of(cx.param_env.and(to_ty))
         && match (from_layout.largest_niche, to_layout.largest_niche) {

src/tools/clippy/lintcheck/src/config.rs

@@ -1,5 +1,5 @@
 use clap::Parser;
-use std::num::NonZeroUsize;
+use std::num::NonZero;
 use std::path::PathBuf;
 
 #[derive(Clone, Debug, Parser)]
@@ -61,7 +61,7 @@ impl LintcheckConfig {
             config.max_jobs = if config.fix || config.recursive {
                 1
             } else {
-                std::thread::available_parallelism().map_or(1, NonZeroUsize::get)
+                std::thread::available_parallelism().map_or(1, NonZero::get)
             };
         };
 

src/tools/clippy/tests/ui/arithmetic_side_effects.rs

@@ -15,7 +15,7 @@
 
 extern crate proc_macro_derive;
 
-use core::num::{NonZeroUsize, Saturating, Wrapping};
+use core::num::{NonZero, Saturating, Wrapping};
 
 const ONE: i32 = 1;
 const ZERO: i32 = 0;
@@ -494,15 +494,15 @@ pub fn issue_11262() {
 }
 
 pub fn issue_11392() {
-    fn example_div(unsigned: usize, nonzero_unsigned: NonZeroUsize) -> usize {
+    fn example_div(unsigned: usize, nonzero_unsigned: NonZero<usize>) -> usize {
         unsigned / nonzero_unsigned
     }
 
-    fn example_rem(unsigned: usize, nonzero_unsigned: NonZeroUsize) -> usize {
+    fn example_rem(unsigned: usize, nonzero_unsigned: NonZero<usize>) -> usize {
         unsigned % nonzero_unsigned
     }
 
-    let (unsigned, nonzero_unsigned) = (0, NonZeroUsize::new(1).unwrap());
+    let (unsigned, nonzero_unsigned) = (0, NonZero::new(1).unwrap());
     example_div(unsigned, nonzero_unsigned);
     example_rem(unsigned, nonzero_unsigned);
 }

src/tools/clippy/tests/ui/eager_transmute.rs

@@ -2,7 +2,7 @@
 #![warn(clippy::eager_transmute)]
 #![allow(clippy::transmute_int_to_non_zero, clippy::missing_transmute_annotations)]
 
-use std::num::NonZeroU8;
+use std::num::NonZero;
 
 #[repr(u8)]
 enum Opcode {
@@ -85,21 +85,21 @@ macro_rules! impls {
 }
 impls!(NonMaxU8, NonZeroNonMaxU8);
 
-fn niche_tests(v1: u8, v2: NonZeroU8, v3: NonZeroNonMaxU8) {
-    // u8 -> NonZeroU8, do lint
-    let _: Option<NonZeroU8> = (v1 > 0).then_some(unsafe { std::mem::transmute(v1) });
+fn niche_tests(v1: u8, v2: NonZero<u8>, v3: NonZeroNonMaxU8) {
+    // u8 -> NonZero<u8>, do lint
+    let _: Option<NonZero<u8>> = (v1 > 0).then_some(unsafe { std::mem::transmute(v1) });
 
-    // NonZeroU8 -> u8, don't lint, target type has no niche and therefore a higher validity range
-    let _: Option<u8> = (v2 > NonZeroU8::new(1).unwrap()).then_some(unsafe { std::mem::transmute(v2) });
+    // NonZero<u8> -> u8, don't lint, target type has no niche and therefore a higher validity range
+    let _: Option<u8> = (v2 > NonZero::new(1u8).unwrap()).then_some(unsafe { std::mem::transmute(v2) });
 
-    // NonZeroU8 -> NonMaxU8, do lint, different niche
-    let _: Option<NonMaxU8> = (v2 < NonZeroU8::new(255).unwrap()).then_some(unsafe { std::mem::transmute(v2) });
+    // NonZero<u8> -> NonMaxU8, do lint, different niche
+    let _: Option<NonMaxU8> = (v2 < NonZero::new(255u8).unwrap()).then_some(unsafe { std::mem::transmute(v2) });
 
     // NonZeroNonMaxU8 -> NonMaxU8, don't lint, target type has more validity
     let _: Option<NonMaxU8> = (v3 < 255).then_some(unsafe { std::mem::transmute(v2) });
 
-    // NonZeroU8 -> NonZeroNonMaxU8, do lint, target type has less validity
-    let _: Option<NonZeroNonMaxU8> = (v2 < NonZeroU8::new(255).unwrap()).then_some(unsafe { std::mem::transmute(v2) });
+    // NonZero<u8> -> NonZeroNonMaxU8, do lint, target type has less validity
+    let _: Option<NonZeroNonMaxU8> = (v2 < NonZero::new(255u8).unwrap()).then_some(unsafe { std::mem::transmute(v2) });
 }
 
 fn main() {}

src/tools/miri/tests/fail/enum-set-discriminant-niche-variant-wrong.rs

@@ -2,7 +2,7 @@
 #![feature(custom_mir)]
 
 use std::intrinsics::mir::*;
-use std::num::NonZeroI32;
+use std::num::NonZero;
 
 // We define our own option type so that we can control the variant indices.
 #[allow(unused)]
@@ -13,7 +13,7 @@ enum Option<T> {
 use Option::*;
 
 #[custom_mir(dialect = "runtime", phase = "optimized")]
-fn set_discriminant(ptr: &mut Option<NonZeroI32>) {
+fn set_discriminant(ptr: &mut Option<NonZero<i32>>) {
     mir! {
         {
             // We set the discriminant to `Some`, which is a NOP since this is the niched variant.

src/tools/miri/tests/fail/function_pointers/abi_mismatch_repr_C.rs

@@ -1,7 +1,7 @@
-use std::num::*;
+use std::num::NonZero;
 
 #[repr(C)]
-struct S1(NonZeroI32);
+struct S1(NonZero<i32>);
 
 #[repr(C)]
 struct S2(i32);
@@ -11,6 +11,6 @@ fn callee(_s: S2) {}
 fn main() {
     let fnptr: fn(S2) = callee;
     let fnptr: fn(S1) = unsafe { std::mem::transmute(fnptr) };
-    fnptr(S1(NonZeroI32::new(1).unwrap()));
+    fnptr(S1(NonZero::new(1).unwrap()));
     //~^ ERROR: calling a function with argument of type S2 passing data of type S1
 }

src/tools/miri/tests/fail/validity/cast_fn_ptr_invalid_callee_ret.rs

@@ -2,15 +2,15 @@
 #![feature(core_intrinsics, custom_mir)]
 
 use std::intrinsics::mir::*;
-use std::num::NonZeroU32;
+use std::num::NonZero;
 use std::ptr;
 
-// This function supposedly returns a NonZeroU32, but actually returns something invalid in a way that
-// never materializes a bad NonZeroU32 value: we take a pointer to the return place and cast the pointer
+// This function supposedly returns a `NonZero<u32>`, but actually returns something invalid in a way that
+// never materializes a bad `NonZero<u32>` value: we take a pointer to the return place and cast the pointer
 // type. That way we never get an "invalid value constructed" error inside the function, it can
 // only possibly be detected when the return value is passed to the caller.
 #[custom_mir(dialect = "runtime", phase = "optimized")]
-fn f() -> NonZeroU32 {
+fn f() -> NonZero<u32> {
     mir! {
         {
             let tmp = ptr::addr_of_mut!(RET);
@@ -22,7 +22,7 @@ fn f() -> NonZeroU32 {
 }
 
 fn main() {
-    let f: fn() -> u32 = unsafe { std::mem::transmute(f as fn() -> NonZeroU32) };
-    // There's a NonZeroU32-to-u32 transmute happening here
+    let f: fn() -> u32 = unsafe { std::mem::transmute(f as fn() -> NonZero<u32>) };
+    // There's a `NonZero<u32>` to `u32` transmute happening here.
     f(); //~ERROR: expected something greater or equal to 1
 }

src/tools/miri/tests/fail/validity/cast_fn_ptr_invalid_caller_arg.rs

@@ -2,24 +2,24 @@
 #![feature(core_intrinsics, custom_mir)]
 
 use std::intrinsics::mir::*;
-use std::num::NonZeroU32;
+use std::num::NonZero;
 use std::ptr;
 
 fn f(c: u32) {
     println!("{c}");
 }
 
-// Call that function in a bad way, with an invalid NonZeroU32, but without
-// ever materializing this as a NonZeroU32 value outside the call itself.
+// Call that function in a bad way, with an invalid `NonZero<u32>`, but without
+// ever materializing this as a `NonZero<u32>` value outside the call itself.
 #[custom_mir(dialect = "runtime", phase = "optimized")]
-fn call(f: fn(NonZeroU32)) {
+fn call(f: fn(NonZero<u32>)) {
     mir! {
         let _res: ();
         {
             let c = 0;
             let tmp = ptr::addr_of!(c);
-            let ptr = tmp as *const NonZeroU32;
-            // The call site now is a NonZeroU32-to-u32 transmute.
+            let ptr = tmp as *const NonZero<u32>;
+            // The call site now is a `NonZero<u32>` to `u32` transmute.
             Call(_res = f(*ptr), ReturnTo(retblock), UnwindContinue()) //~ERROR: expected something greater or equal to 1
         }
         retblock = {
@@ -29,6 +29,6 @@ fn call(f: fn(NonZeroU32)) {
 }
 
 fn main() {
-    let f: fn(NonZeroU32) = unsafe { std::mem::transmute(f as fn(u32)) };
+    let f: fn(NonZero<u32>) = unsafe { std::mem::transmute(f as fn(u32)) };
     call(f);
 }

src/tools/miri/tests/pass/available-parallelism-miri-num-cpus.rs

@@ -1,8 +1,8 @@
 //@compile-flags: -Zmiri-num-cpus=1024
 
-use std::num::NonZeroUsize;
+use std::num::NonZero;
 use std::thread::available_parallelism;
 
 fn main() {
-    assert_eq!(available_parallelism().unwrap(), NonZeroUsize::new(1024).unwrap());
+    assert_eq!(available_parallelism().unwrap(), NonZero::new(1024).unwrap());
 }

src/tools/miri/tests/pass/function_calls/abi_compat.rs

@@ -70,7 +70,7 @@ fn main() {
         test_abi_compat(0usize, 0u64);
         test_abi_compat(0isize, 0i64);
     }
-    test_abi_compat(42u32, num::NonZeroU32::new(1).unwrap());
+    test_abi_compat(42u32, num::NonZero::new(1u32).unwrap());
     // - `char` and `u32`.
     test_abi_compat(42u32, 'x');
     // - Reference/pointer types with the same pointee.
@@ -86,9 +86,9 @@ fn main() {
     // - Guaranteed null-pointer-optimizations (RFC 3391).
     test_abi_compat(&0u32 as *const u32, Some(&0u32));
     test_abi_compat(main as fn(), Some(main as fn()));
-    test_abi_compat(0u32, Some(num::NonZeroU32::new(1).unwrap()));
+    test_abi_compat(0u32, Some(num::NonZero::new(1u32).unwrap()));
     test_abi_compat(&0u32 as *const u32, Some(Wrapper(&0u32)));
-    test_abi_compat(0u32, Some(Wrapper(num::NonZeroU32::new(1).unwrap())));
+    test_abi_compat(0u32, Some(Wrapper(num::NonZero::new(1u32).unwrap())));
 
     // These must work for *any* type, since we guarantee that `repr(transparent)` is ABI-compatible
     // with the wrapped field.
@@ -102,7 +102,7 @@ fn main() {
     test_abi_newtype::<[u32; 2]>();
     test_abi_newtype::<[u32; 32]>();
     test_abi_newtype::<Option<i32>>();
-    test_abi_newtype::<Option<num::NonZeroU32>>();
+    test_abi_newtype::<Option<num::NonZero<u32>>>();
 
     // Extra test for assumptions made by arbitrary-self-dyn-receivers.
     // This is interesting since these types are not `repr(transparent)`. So this is not part of our

src/tools/miri/tests/ui.rs

@@ -1,5 +1,5 @@
 use std::ffi::OsString;
-use std::num::NonZeroUsize;
+use std::num::NonZero;
 use std::path::{Path, PathBuf};
 use std::sync::OnceLock;
 use std::{env, process::Command};
@@ -76,7 +76,7 @@ fn miri_config(target: &str, path: &str, mode: Mode, with_dependencies: bool) ->
         edition: Some("2021".into()), // keep in sync with `./miri run`
         threads: std::env::var("MIRI_TEST_THREADS")
             .ok()
-            .map(|threads| NonZeroUsize::new(threads.parse().unwrap()).unwrap()),
+            .map(|threads| NonZero::new(threads.parse().unwrap()).unwrap()),
         ..Config::rustc(path)
     };
 

tests/ui-fulldeps/stable-mir/check_abi.rs

@@ -99,7 +99,7 @@ fn check_result(abi: &ArgAbi) {
     assert_matches!(layout.variants, VariantsShape::Multiple { .. })
 }
 
-/// Check the niche information about: `NonZeroU8`
+/// Checks the niche information about `NonZero<u8>`.
 fn check_niche(abi: &ArgAbi) {
     assert!(abi.ty.kind().is_struct());
     assert_matches!(abi.mode, PassMode::Direct { .. });
@@ -150,12 +150,12 @@ fn generate_input(path: &str) -> std::io::Result<()> {
         #![feature(c_variadic)]
         #![allow(unused_variables)]
 
-        use std::num::NonZeroU8;
+        use std::num::NonZero;
 
         pub fn fn_abi(
             ignore: [u8; 0],
             primitive: char,
-            niche: NonZeroU8,
+            niche: NonZero<u8>,
         ) -> Result<usize, &'static str> {{
                 // We only care about the signature.
                 todo!()