Use generic NonZero internally.

compiler/rustc_attr/src/builtin.rs

@@ -13,7 +13,7 @@ use rustc_session::parse::feature_err;
 use rustc_session::{RustcVersion, Session};
 use rustc_span::hygiene::Transparency;
 use rustc_span::{symbol::sym, symbol::Symbol, Span};
-use std::num::NonZeroU32;
+use std::num::NonZero;
 
 use crate::session_diagnostics::{self, IncorrectReprFormatGenericCause};
 
@@ -113,7 +113,7 @@ pub enum StabilityLevel {
         /// Reason for the current stability level.
         reason: UnstableReason,
         /// Relevant `rust-lang/rust` issue.
-        issue: Option<NonZeroU32>,
+        issue: Option<NonZero<u32>>,
         is_soft: bool,
         /// If part of a feature is stabilized and a new feature is added for the remaining parts,
         /// then the `implied_by` attribute is used to indicate which now-stable feature previously
@@ -442,7 +442,7 @@ fn parse_unstability(sess: &Session, attr: &Attribute) -> Option<(Symbol, Stabil
                 // is a name/value pair string literal.
                 issue_num = match issue.unwrap().as_str() {
                     "none" => None,
-                    issue => match issue.parse::<NonZeroU32>() {
+                    issue => match issue.parse::<NonZero<u32>>() {
                         Ok(num) => Some(num),
                         Err(err) => {
                             sess.dcx().emit_err(

compiler/rustc_attr/src/lib.rs

@@ -7,6 +7,7 @@
 #![allow(internal_features)]
 #![feature(rustdoc_internals)]
 #![doc(rust_logo)]
+#![feature(generic_nonzero)]
 #![feature(let_chains)]
 
 #[macro_use]

compiler/rustc_const_eval/src/interpret/validity.rs

@@ -5,7 +5,7 @@
 //! to be const-safe.
 
 use std::fmt::Write;
-use std::num::NonZeroUsize;
+use std::num::NonZero;
 
 use either::{Left, Right};
 
@@ -782,7 +782,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValueVisitor<'mir, 'tcx, M>
     fn visit_union(
         &mut self,
         op: &OpTy<'tcx, M::Provenance>,
-        _fields: NonZeroUsize,
+        _fields: NonZero<usize>,
     ) -> InterpResult<'tcx> {
         // Special check for CTFE validation, preventing `UnsafeCell` inside unions in immutable memory.
         if self.ctfe_mode.is_some_and(|c| !c.allow_immutable_unsafe_cell()) {

compiler/rustc_const_eval/src/interpret/visitor.rs

@@ -7,7 +7,7 @@ use rustc_middle::ty;
 use rustc_target::abi::FieldIdx;
 use rustc_target::abi::{FieldsShape, VariantIdx, Variants};
 
-use std::num::NonZeroUsize;
+use std::num::NonZero;
 
 use super::{InterpCx, MPlaceTy, Machine, Projectable};
 
@@ -43,7 +43,7 @@ pub trait ValueVisitor<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>>: Sized {
     }
     /// Visits the given value as a union. No automatic recursion can happen here.
     #[inline(always)]
-    fn visit_union(&mut self, _v: &Self::V, _fields: NonZeroUsize) -> InterpResult<'tcx> {
+    fn visit_union(&mut self, _v: &Self::V, _fields: NonZero<usize>) -> InterpResult<'tcx> {
         Ok(())
     }
     /// Visits the given value as the pointer of a `Box`. There is nothing to recurse into.

compiler/rustc_const_eval/src/lib.rs

@@ -11,6 +11,7 @@ Rust MIR: a lowered representation of Rust.
 #![feature(assert_matches)]
 #![feature(box_patterns)]
 #![feature(decl_macro)]
+#![feature(generic_nonzero)]
 #![feature(let_chains)]
 #![feature(slice_ptr_get)]
 #![feature(never_type)]

compiler/rustc_data_structures/src/lib.rs

@@ -20,6 +20,7 @@
 #![feature(cfg_match)]
 #![feature(core_intrinsics)]
 #![feature(extend_one)]
+#![feature(generic_nonzero)]
 #![feature(hash_raw_entry)]
 #![feature(hasher_prefixfree_extras)]
 #![feature(lazy_cell)]

compiler/rustc_data_structures/src/stable_hasher.rs

@@ -6,6 +6,7 @@ use std::fmt;
 use std::hash::{BuildHasher, Hash, Hasher};
 use std::marker::PhantomData;
 use std::mem;
+use std::num::NonZero;
 
 #[cfg(test)]
 mod tests;
@@ -338,14 +339,14 @@ impl<CTX, T> HashStable<CTX> for PhantomData<T> {
     fn hash_stable(&self, _ctx: &mut CTX, _hasher: &mut StableHasher) {}
 }
 
-impl<CTX> HashStable<CTX> for ::std::num::NonZeroU32 {
+impl<CTX> HashStable<CTX> for NonZero<u32> {
     #[inline]
     fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
         self.get().hash_stable(ctx, hasher)
     }
 }
 
-impl<CTX> HashStable<CTX> for ::std::num::NonZeroUsize {
+impl<CTX> HashStable<CTX> for NonZero<usize> {
     #[inline]
     fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
         self.get().hash_stable(ctx, hasher)

compiler/rustc_data_structures/src/sync/worker_local.rs

@@ -1,7 +1,7 @@
 use parking_lot::Mutex;
 use std::cell::Cell;
 use std::cell::OnceCell;
-use std::num::NonZeroUsize;
+use std::num::NonZero;
 use std::ops::Deref;
 use std::ptr;
 use std::sync::Arc;
@@ -31,7 +31,7 @@ impl RegistryId {
 }
 
 struct RegistryData {
-    thread_limit: NonZeroUsize,
+    thread_limit: NonZero<usize>,
     threads: Mutex<usize>,
 }
 
@@ -61,7 +61,7 @@ thread_local! {
 
 impl Registry {
     /// Creates a registry which can hold up to `thread_limit` threads.
-    pub fn new(thread_limit: NonZeroUsize) -> Self {
+    pub fn new(thread_limit: NonZero<usize>) -> Self {
         Registry(Arc::new(RegistryData { thread_limit, threads: Mutex::new(0) }))
     }
 

compiler/rustc_data_structures/src/tagged_ptr/copy.rs

@@ -4,7 +4,7 @@ use std::fmt;
 use std::hash::{Hash, Hasher};
 use std::marker::PhantomData;
 use std::mem::ManuallyDrop;
-use std::num::NonZeroUsize;
+use std::num::NonZero;
 use std::ops::{Deref, DerefMut};
 use std::ptr::NonNull;
 
@@ -134,7 +134,7 @@ where
 
         ptr.map_addr(|addr| {
             // Safety:
-            // - The pointer is `NonNull` => it's address is `NonZeroUsize`
+            // - The pointer is `NonNull` => it's address is `NonZero<usize>`
             // - `P::BITS` least significant bits are always zero (`Pointer` contract)
             // - `T::BITS <= P::BITS` (from `Self::ASSERTION`)
             //
@@ -143,14 +143,15 @@ where
             // `{non_zero} | packed_tag` can't make the value zero.
 
             let packed = (addr.get() >> T::BITS) | packed_tag;
-            unsafe { NonZeroUsize::new_unchecked(packed) }
+            unsafe { NonZero::<usize>::new_unchecked(packed) }
         })
     }
 
     /// Retrieves the original raw pointer from `self.packed`.
     #[inline]
     pub(super) fn pointer_raw(&self) -> NonNull<P::Target> {
-        self.packed.map_addr(|addr| unsafe { NonZeroUsize::new_unchecked(addr.get() << T::BITS) })
+        self.packed
+            .map_addr(|addr| unsafe { NonZero::<usize>::new_unchecked(addr.get() << T::BITS) })
     }
 
     /// This provides a reference to the `P` pointer itself, rather than the

compiler/rustc_errors/src/diagnostic_impls.rs

@@ -79,7 +79,7 @@ into_diagnostic_arg_using_display!(
     ast::ParamKindOrd,
     std::io::Error,
     Box<dyn std::error::Error>,
-    std::num::NonZeroU32,
+    std::num::NonZero<u32>,
     hir::Target,
     Edition,
     Ident,

compiler/rustc_errors/src/lib.rs

@@ -16,6 +16,7 @@
 #![feature(box_patterns)]
 #![feature(error_reporter)]
 #![feature(extract_if)]
+#![feature(generic_nonzero)]
 #![feature(let_chains)]
 #![feature(negative_impls)]
 #![feature(never_type)]
@@ -77,7 +78,7 @@ use std::error::Report;
 use std::fmt;
 use std::hash::Hash;
 use std::io::Write;
-use std::num::NonZeroUsize;
+use std::num::NonZero;
 use std::ops::DerefMut;
 use std::panic;
 use std::path::{Path, PathBuf};
@@ -545,7 +546,7 @@ pub struct DiagCtxtFlags {
     pub can_emit_warnings: bool,
     /// If Some, the Nth error-level diagnostic is upgraded to bug-level.
     /// (rustc: see `-Z treat-err-as-bug`)
-    pub treat_err_as_bug: Option<NonZeroUsize>,
+    pub treat_err_as_bug: Option<NonZero<usize>>,
     /// Eagerly emit delayed bugs as errors, so that the compiler debugger may
     /// see all of the errors being emitted at once.
     pub eagerly_emit_delayed_bugs: bool,

compiler/rustc_feature/src/lib.rs

@@ -12,6 +12,7 @@
 //! symbol to the `accepted` or `removed` modules respectively.
 
 #![allow(internal_features)]
+#![feature(generic_nonzero)]
 #![feature(rustdoc_internals)]
 #![doc(rust_logo)]
 #![feature(lazy_cell)]
@@ -25,13 +26,13 @@ mod unstable;
 mod tests;
 
 use rustc_span::symbol::Symbol;
-use std::num::NonZeroU32;
+use std::num::NonZero;
 
 #[derive(Debug, Clone)]
 pub struct Feature {
     pub name: Symbol,
     pub since: &'static str,
-    issue: Option<NonZeroU32>,
+    issue: Option<NonZero<u32>>,
 }
 
 #[derive(Copy, Clone, Debug)]
@@ -85,7 +86,7 @@ impl UnstableFeatures {
     }
 }
 
-fn find_lang_feature_issue(feature: Symbol) -> Option<NonZeroU32> {
+fn find_lang_feature_issue(feature: Symbol) -> Option<NonZero<u32>> {
     // Search in all the feature lists.
     if let Some(f) = UNSTABLE_FEATURES.iter().find(|f| f.feature.name == feature) {
         return f.feature.issue;
@@ -99,21 +100,21 @@ fn find_lang_feature_issue(feature: Symbol) -> Option<NonZeroU32> {
     panic!("feature `{feature}` is not declared anywhere");
 }
 
-const fn to_nonzero(n: Option<u32>) -> Option<NonZeroU32> {
-    // Can be replaced with `n.and_then(NonZeroU32::new)` if that is ever usable
+const fn to_nonzero(n: Option<u32>) -> Option<NonZero<u32>> {
+    // Can be replaced with `n.and_then(NonZero::new)` if that is ever usable
     // in const context. Requires https://github.com/rust-lang/rfcs/pull/2632.
     match n {
         None => None,
-        Some(n) => NonZeroU32::new(n),
+        Some(n) => NonZero::<u32>::new(n),
     }
 }
 
 pub enum GateIssue {
     Language,
-    Library(Option<NonZeroU32>),
+    Library(Option<NonZero<u32>>),
 }
 
-pub fn find_feature_issue(feature: Symbol, issue: GateIssue) -> Option<NonZeroU32> {
+pub fn find_feature_issue(feature: Symbol, issue: GateIssue) -> Option<NonZero<u32>> {
     match issue {
         GateIssue::Language => find_lang_feature_issue(feature),
         GateIssue::Library(lib) => lib,

compiler/rustc_hir_analysis/src/check/mod.rs

@@ -74,7 +74,7 @@ pub mod wfcheck;
 
 pub use check::check_abi;
 
-use std::num::NonZeroU32;
+use std::num::NonZero;
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::ErrorGuaranteed;
@@ -270,7 +270,7 @@ fn default_body_is_unstable(
     item_did: DefId,
     feature: Symbol,
     reason: Option<Symbol>,
-    issue: Option<NonZeroU32>,
+    issue: Option<NonZero<u32>>,
 ) {
     let missing_item_name = tcx.associated_item(item_did).name;
     let (mut some_note, mut none_note, mut reason_str) = (false, false, String::new());

compiler/rustc_hir_analysis/src/lib.rs

@@ -63,6 +63,7 @@ This API is completely unstable and subject to change.
 #![feature(rustdoc_internals)]
 #![allow(internal_features)]
 #![feature(control_flow_enum)]
+#![feature(generic_nonzero)]
 #![feature(if_let_guard)]
 #![feature(is_sorted)]
 #![feature(iter_intersperse)]

compiler/rustc_interface/src/lib.rs

@@ -1,5 +1,6 @@
 #![feature(decl_macro)]
 #![feature(error_iter)]
+#![feature(generic_nonzero)]
 #![feature(lazy_cell)]
 #![feature(let_chains)]
 #![feature(thread_spawn_unchecked)]

compiler/rustc_interface/src/tests.rs

@@ -20,7 +20,7 @@ use rustc_span::{FileName, SourceFileHashAlgorithm};
 use rustc_target::spec::{CodeModel, LinkerFlavorCli, MergeFunctions, PanicStrategy, RelocModel};
 use rustc_target::spec::{RelroLevel, SanitizerSet, SplitDebuginfo, StackProtector, TlsModel};
 use std::collections::{BTreeMap, BTreeSet};
-use std::num::NonZeroUsize;
+use std::num::NonZero;
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
 
@@ -827,7 +827,7 @@ fn test_unstable_options_tracking_hash() {
     tracked!(tls_model, Some(TlsModel::GeneralDynamic));
     tracked!(translate_remapped_path_to_local_path, false);
     tracked!(trap_unreachable, Some(false));
-    tracked!(treat_err_as_bug, NonZeroUsize::new(1));
+    tracked!(treat_err_as_bug, NonZero::<usize>::new(1));
     tracked!(tune_cpu, Some(String::from("abc")));
     tracked!(uninit_const_chunk_threshold, 123);
     tracked!(unleash_the_miri_inside_of_you, true);

compiler/rustc_interface/src/util.rs

@@ -107,7 +107,7 @@ pub(crate) fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
     use rustc_query_impl::QueryCtxt;
     use rustc_query_system::query::{deadlock, QueryContext};
 
-    let registry = sync::Registry::new(std::num::NonZeroUsize::new(threads).unwrap());
+    let registry = sync::Registry::new(std::num::NonZero::<usize>::new(threads).unwrap());
 
     if !sync::is_dyn_thread_safe() {
         return run_in_thread_with_globals(edition, || {

compiler/rustc_lint/src/lib.rs

@@ -31,6 +31,7 @@
 #![feature(array_windows)]
 #![feature(box_patterns)]
 #![feature(control_flow_enum)]
+#![feature(generic_nonzero)]
 #![feature(if_let_guard)]
 #![feature(iter_order_by)]
 #![feature(let_chains)]

compiler/rustc_lint/src/lints.rs

@@ -1,7 +1,6 @@
 #![allow(rustc::diagnostic_outside_of_impl)]
 #![allow(rustc::untranslatable_diagnostic)]
-
-use std::num::NonZeroU32;
+use std::num::NonZero;
 
 use crate::errors::RequestedLevel;
 use crate::fluent_generated as fluent;
@@ -402,7 +401,7 @@ pub struct BuiltinIncompleteFeaturesHelp;
 #[derive(Subdiagnostic)]
 #[note(lint_note)]
 pub struct BuiltinFeatureIssueNote {
-    pub n: NonZeroU32,
+    pub n: NonZero<u32>,
 }
 
 pub struct BuiltinUnpermittedTypeInit<'a> {

compiler/rustc_metadata/src/lib.rs

@@ -5,6 +5,7 @@
 #![feature(decl_macro)]
 #![feature(extract_if)]
 #![feature(coroutines)]
+#![feature(generic_nonzero)]
 #![feature(iter_from_coroutine)]
 #![feature(let_chains)]
 #![feature(if_let_guard)]

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -327,7 +327,7 @@ impl<'a, 'tcx> DecodeContext<'a, 'tcx> {
     }
 
     #[inline]
-    fn read_lazy_offset_then<T>(&mut self, f: impl Fn(NonZeroUsize) -> T) -> T {
+    fn read_lazy_offset_then<T>(&mut self, f: impl Fn(NonZero<usize>) -> T) -> T {
         let distance = self.read_usize();
         let position = match self.lazy_state {
             LazyState::NoNode => bug!("read_lazy_with_meta: outside of a metadata node"),
@@ -338,7 +338,7 @@ impl<'a, 'tcx> DecodeContext<'a, 'tcx> {
             }
             LazyState::Previous(last_pos) => last_pos.get() + distance,
         };
-        let position = NonZeroUsize::new(position).unwrap();
+        let position = NonZero::<usize>::new(position).unwrap();
         self.lazy_state = LazyState::Previous(position);
         f(position)
     }
@@ -685,15 +685,17 @@ impl MetadataBlob {
     }
 
     pub(crate) fn get_rustc_version(&self) -> String {
-        LazyValue::<String>::from_position(NonZeroUsize::new(METADATA_HEADER.len() + 8).unwrap())
-            .decode(self)
+        LazyValue::<String>::from_position(
+            NonZero::<usize>::new(METADATA_HEADER.len() + 8).unwrap(),
+        )
+        .decode(self)
     }
 
-    fn root_pos(&self) -> NonZeroUsize {
+    fn root_pos(&self) -> NonZero<usize> {
         let offset = METADATA_HEADER.len();
         let pos_bytes = self.blob()[offset..][..8].try_into().unwrap();
         let pos = u64::from_le_bytes(pos_bytes);
-        NonZeroUsize::new(pos as usize).unwrap()
+        NonZero::<usize>::new(pos as usize).unwrap()
     }
 
     pub(crate) fn get_header(&self) -> CrateHeader {

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -421,7 +421,7 @@ macro_rules! record_defaulted_array {
 }
 
 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
-    fn emit_lazy_distance(&mut self, position: NonZeroUsize) {
+    fn emit_lazy_distance(&mut self, position: NonZero<usize>) {
         let pos = position.get();
         let distance = match self.lazy_state {
             LazyState::NoNode => bug!("emit_lazy_distance: outside of a metadata node"),
@@ -439,7 +439,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 position.get() - last_pos.get()
             }
         };
-        self.lazy_state = LazyState::Previous(NonZeroUsize::new(pos).unwrap());
+        self.lazy_state = LazyState::Previous(NonZero::<usize>::new(pos).unwrap());
         self.emit_usize(distance);
     }
 
@@ -447,7 +447,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
     where
         T::Value<'tcx>: Encodable<EncodeContext<'a, 'tcx>>,
     {
-        let pos = NonZeroUsize::new(self.position()).unwrap();
+        let pos = NonZero::<usize>::new(self.position()).unwrap();
 
         assert_eq!(self.lazy_state, LazyState::NoNode);
         self.lazy_state = LazyState::NodeStart(pos);
@@ -466,7 +466,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
     where
         T::Value<'tcx>: Encodable<EncodeContext<'a, 'tcx>>,
     {
-        let pos = NonZeroUsize::new(self.position()).unwrap();
+        let pos = NonZero::<usize>::new(self.position()).unwrap();
 
         assert_eq!(self.lazy_state, LazyState::NoNode);
         self.lazy_state = LazyState::NodeStart(pos);

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -37,7 +37,7 @@ use rustc_target::abi::{FieldIdx, VariantIdx};
 use rustc_target::spec::{PanicStrategy, TargetTriple};
 
 use std::marker::PhantomData;
-use std::num::NonZeroUsize;
+use std::num::NonZero;
 
 use decoder::DecodeContext;
 pub(crate) use decoder::{CrateMetadata, CrateNumMap, MetadataBlob};
@@ -83,7 +83,7 @@ pub const METADATA_HEADER: &[u8] = &[b'r', b'u', b's', b't', 0, 0, 0, METADATA_V
 /// order than they were encoded in.
 #[must_use]
 struct LazyValue<T> {
-    position: NonZeroUsize,
+    position: NonZero<usize>,
     _marker: PhantomData<fn() -> T>,
 }
 
@@ -92,7 +92,7 @@ impl<T: ParameterizedOverTcx> ParameterizedOverTcx for LazyValue<T> {
 }
 
 impl<T> LazyValue<T> {
-    fn from_position(position: NonZeroUsize) -> LazyValue<T> {
+    fn from_position(position: NonZero<usize>) -> LazyValue<T> {
         LazyValue { position, _marker: PhantomData }
     }
 }
@@ -108,7 +108,7 @@ impl<T> LazyValue<T> {
 /// the minimal distance the length of the sequence, i.e.
 /// it's assumed there's no 0-byte element in the sequence.
 struct LazyArray<T> {
-    position: NonZeroUsize,
+    position: NonZero<usize>,
     num_elems: usize,
     _marker: PhantomData<fn() -> T>,
 }
@@ -119,12 +119,12 @@ impl<T: ParameterizedOverTcx> ParameterizedOverTcx for LazyArray<T> {
 
 impl<T> Default for LazyArray<T> {
     fn default() -> LazyArray<T> {
-        LazyArray::from_position_and_num_elems(NonZeroUsize::new(1).unwrap(), 0)
+        LazyArray::from_position_and_num_elems(NonZero::<usize>::new(1).unwrap(), 0)
     }
 }
 
 impl<T> LazyArray<T> {
-    fn from_position_and_num_elems(position: NonZeroUsize, num_elems: usize) -> LazyArray<T> {
+    fn from_position_and_num_elems(position: NonZero<usize>, num_elems: usize) -> LazyArray<T> {
         LazyArray { position, num_elems, _marker: PhantomData }
     }
 }
@@ -135,7 +135,7 @@ impl<T> LazyArray<T> {
 /// `LazyArray<T>`, but without requiring encoding or decoding all the values
 /// eagerly and in-order.
 struct LazyTable<I, T> {
-    position: NonZeroUsize,
+    position: NonZero<usize>,
     /// The encoded size of the elements of a table is selected at runtime to drop
     /// trailing zeroes. This is the number of bytes used for each table element.
     width: usize,
@@ -150,7 +150,7 @@ impl<I: 'static, T: ParameterizedOverTcx> ParameterizedOverTcx for LazyTable<I,
 
 impl<I, T> LazyTable<I, T> {
     fn from_position_and_encoded_size(
-        position: NonZeroUsize,
+        position: NonZero<usize>,
         width: usize,
         len: usize,
     ) -> LazyTable<I, T> {
@@ -187,11 +187,11 @@ enum LazyState {
 
     /// Inside a metadata node, and before any `Lazy`s.
     /// The position is that of the node itself.
-    NodeStart(NonZeroUsize),
+    NodeStart(NonZero<usize>),
 
     /// Inside a metadata node, with a previous `Lazy`s.
     /// The position is where that previous `Lazy` would start.
-    Previous(NonZeroUsize),
+    Previous(NonZero<usize>),
 }
 
 type SyntaxContextTable = LazyTable<u32, Option<LazyValue<SyntaxContextData>>>;

compiler/rustc_metadata/src/rmeta/table.rs

@@ -339,7 +339,7 @@ impl<T> FixedSizeEncoding for Option<LazyValue<T>> {
 
     #[inline]
     fn from_bytes(b: &[u8; 8]) -> Self {
-        let position = NonZeroUsize::new(u64::from_bytes(b) as usize)?;
+        let position = NonZero::<usize>::new(u64::from_bytes(b) as usize)?;
         Some(LazyValue::from_position(position))
     }
 
@@ -366,7 +366,7 @@ impl<T> LazyArray<T> {
     }
 
     fn from_bytes_impl(position: &[u8; 8], meta: &[u8; 8]) -> Option<LazyArray<T>> {
-        let position = NonZeroUsize::new(u64::from_bytes(position) as usize)?;
+        let position = NonZero::<usize>::new(u64::from_bytes(position) as usize)?;
         let len = u64::from_bytes(meta) as usize;
         Some(LazyArray::from_position_and_num_elems(position, len))
     }
@@ -497,7 +497,7 @@ impl<I: Idx, const N: usize, T: FixedSizeEncoding<ByteArray = [u8; N]>> TableBui
         }
 
         LazyTable::from_position_and_encoded_size(
-            NonZeroUsize::new(pos).unwrap(),
+            NonZero::<usize>::new(pos).unwrap(),
             width,
             self.blocks.len(),
         )

compiler/rustc_middle/src/lib.rs

@@ -34,6 +34,7 @@
 #![feature(discriminant_kind)]
 #![feature(exhaustive_patterns)]
 #![feature(coroutines)]
+#![feature(generic_nonzero)]
 #![feature(if_let_guard)]
 #![feature(inline_const)]
 #![feature(iter_from_coroutine)]

compiler/rustc_middle/src/middle/stability.rs

@@ -21,7 +21,7 @@ use rustc_session::parse::feature_err_issue;
 use rustc_session::Session;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
-use std::num::NonZeroU32;
+use std::num::NonZero;
 
 #[derive(PartialEq, Clone, Copy, Debug)]
 pub enum StabilityLevel {
@@ -102,7 +102,7 @@ pub fn report_unstable(
     sess: &Session,
     feature: Symbol,
     reason: Option<Symbol>,
-    issue: Option<NonZeroU32>,
+    issue: Option<NonZero<u32>>,
     suggestion: Option<(Span, String, String, Applicability)>,
     is_soft: bool,
     span: Span,
@@ -235,7 +235,7 @@ pub enum EvalResult {
     Deny {
         feature: Symbol,
         reason: Option<Symbol>,
-        issue: Option<NonZeroU32>,
+        issue: Option<NonZero<u32>>,
         suggestion: Option<(Span, String, String, Applicability)>,
         is_soft: bool,
     },
@@ -433,7 +433,7 @@ impl<'tcx> TyCtxt<'tcx> {
                 // the `-Z force-unstable-if-unmarked` flag present (we're
                 // compiling a compiler crate), then let this missing feature
                 // annotation slide.
-                if feature == sym::rustc_private && issue == NonZeroU32::new(27812) {
+                if feature == sym::rustc_private && issue == NonZero::<u32>::new(27812) {
                     if self.sess.opts.unstable_opts.force_unstable_if_unmarked {
                         return EvalResult::Allow;
                     }

compiler/rustc_middle/src/mir/interpret/mod.rs

@@ -122,7 +122,7 @@ mod value;
 use std::fmt;
 use std::io;
 use std::io::{Read, Write};
-use std::num::{NonZeroU32, NonZeroU64};
+use std::num::NonZero;
 use std::sync::atomic::{AtomicU32, Ordering};
 
 use rustc_ast::LitKind;
@@ -205,7 +205,7 @@ pub enum LitToConstError {
 }
 
 #[derive(Copy, Clone, Eq, Hash, Ord, PartialEq, PartialOrd)]
-pub struct AllocId(pub NonZeroU64);
+pub struct AllocId(pub NonZero<u64>);
 
 // We want the `Debug` output to be readable as it is used by `derive(Debug)` for
 // all the Miri types.
@@ -260,7 +260,7 @@ pub fn specialized_encode_alloc_id<'tcx, E: TyEncoder<I = TyCtxt<'tcx>>>(
 }
 
 // Used to avoid infinite recursion when decoding cyclic allocations.
-type DecodingSessionId = NonZeroU32;
+type DecodingSessionId = NonZero<u32>;
 
 #[derive(Clone)]
 enum State {
@@ -500,7 +500,7 @@ impl<'tcx> AllocMap<'tcx> {
         AllocMap {
             alloc_map: Default::default(),
             dedup: Default::default(),
-            next_id: AllocId(NonZeroU64::new(1).unwrap()),
+            next_id: AllocId(NonZero::<u64>::new(1).unwrap()),
         }
     }
     fn reserve(&mut self) -> AllocId {

compiler/rustc_middle/src/mir/interpret/pointer.rs

@@ -3,7 +3,7 @@ use super::{AllocId, InterpResult};
 use rustc_macros::HashStable;
 use rustc_target::abi::{HasDataLayout, Size};
 
-use std::{fmt, num::NonZeroU64};
+use std::{fmt, num::NonZero};
 
 ////////////////////////////////////////////////////////////////////////////////
 // Pointer arithmetic
@@ -129,7 +129,7 @@ pub trait Provenance: Copy + fmt::Debug + 'static {
 /// The type of provenance in the compile-time interpreter.
 /// This is a packed representation of an `AllocId` and an `immutable: bool`.
 #[derive(Copy, Clone, Eq, Hash, Ord, PartialEq, PartialOrd)]
-pub struct CtfeProvenance(NonZeroU64);
+pub struct CtfeProvenance(NonZero<u64>);
 
 impl From<AllocId> for CtfeProvenance {
     fn from(value: AllocId) -> Self {
@@ -155,7 +155,7 @@ impl CtfeProvenance {
     /// Returns the `AllocId` of this provenance.
     #[inline(always)]
     pub fn alloc_id(self) -> AllocId {
-        AllocId(NonZeroU64::new(self.0.get() & !IMMUTABLE_MASK).unwrap())
+        AllocId(NonZero::<u64>::new(self.0.get() & !IMMUTABLE_MASK).unwrap())
     }
 
     /// Returns whether this provenance is immutable.

compiler/rustc_middle/src/ty/consts/int.rs

@@ -4,7 +4,7 @@ use rustc_errors::{DiagnosticArgValue, IntoDiagnosticArg};
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 use rustc_target::abi::Size;
 use std::fmt;
-use std::num::NonZeroU8;
+use std::num::NonZero;
 
 use crate::ty::TyCtxt;
 
@@ -132,7 +132,7 @@ pub struct ScalarInt {
     /// The first `size` bytes of `data` are the value.
     /// Do not try to read less or more bytes than that. The remaining bytes must be 0.
     data: u128,
-    size: NonZeroU8,
+    size: NonZero<u8>,
 }
 
 // Cannot derive these, as the derives take references to the fields, and we
@@ -161,14 +161,14 @@ impl<D: Decoder> Decodable<D> for ScalarInt {
         let mut data = [0u8; 16];
         let size = d.read_u8();
         data[..size as usize].copy_from_slice(d.read_raw_bytes(size as usize));
-        ScalarInt { data: u128::from_le_bytes(data), size: NonZeroU8::new(size).unwrap() }
+        ScalarInt { data: u128::from_le_bytes(data), size: NonZero::<u8>::new(size).unwrap() }
     }
 }
 
 impl ScalarInt {
-    pub const TRUE: ScalarInt = ScalarInt { data: 1_u128, size: NonZeroU8::new(1).unwrap() };
+    pub const TRUE: ScalarInt = ScalarInt { data: 1_u128, size: NonZero::<u8>::new(1).unwrap() };
 
-    pub const FALSE: ScalarInt = ScalarInt { data: 0_u128, size: NonZeroU8::new(1).unwrap() };
+    pub const FALSE: ScalarInt = ScalarInt { data: 0_u128, size: NonZero::<u8>::new(1).unwrap() };
 
     #[inline]
     pub fn size(self) -> Size {
@@ -196,7 +196,7 @@ impl ScalarInt {
 
     #[inline]
     pub fn null(size: Size) -> Self {
-        Self { data: 0, size: NonZeroU8::new(size.bytes() as u8).unwrap() }
+        Self { data: 0, size: NonZero::<u8>::new(size.bytes() as u8).unwrap() }
     }
 
     #[inline]
@@ -208,7 +208,7 @@ impl ScalarInt {
     pub fn try_from_uint(i: impl Into<u128>, size: Size) -> Option<Self> {
         let data = i.into();
         if size.truncate(data) == data {
-            Some(Self { data, size: NonZeroU8::new(size.bytes() as u8).unwrap() })
+            Some(Self { data, size: NonZero::<u8>::new(size.bytes() as u8).unwrap() })
         } else {
             None
         }
@@ -220,7 +220,7 @@ impl ScalarInt {
         // `into` performed sign extension, we have to truncate
         let truncated = size.truncate(i as u128);
         if size.sign_extend(truncated) as i128 == i {
-            Some(Self { data: truncated, size: NonZeroU8::new(size.bytes() as u8).unwrap() })
+            Some(Self { data: truncated, size: NonZero::<u8>::new(size.bytes() as u8).unwrap() })
         } else {
             None
         }
@@ -388,7 +388,7 @@ macro_rules! from {
                 fn from(u: $ty) -> Self {
                     Self {
                         data: u128::from(u),
-                        size: NonZeroU8::new(std::mem::size_of::<$ty>() as u8).unwrap(),
+                        size: NonZero::<u8>::new(std::mem::size_of::<$ty>() as u8).unwrap(),
                     }
                 }
             }
@@ -427,7 +427,10 @@ impl TryFrom<ScalarInt> for bool {
 impl From<char> for ScalarInt {
     #[inline]
     fn from(c: char) -> Self {
-        Self { data: c as u128, size: NonZeroU8::new(std::mem::size_of::<char>() as u8).unwrap() }
+        Self {
+            data: c as u128,
+            size: NonZero::<u8>::new(std::mem::size_of::<char>() as u8).unwrap(),
+        }
     }
 }
 
@@ -454,7 +457,7 @@ impl From<Single> for ScalarInt {
     #[inline]
     fn from(f: Single) -> Self {
         // We trust apfloat to give us properly truncated data.
-        Self { data: f.to_bits(), size: NonZeroU8::new((Single::BITS / 8) as u8).unwrap() }
+        Self { data: f.to_bits(), size: NonZero::<u8>::new((Single::BITS / 8) as u8).unwrap() }
     }
 }
 
@@ -470,7 +473,7 @@ impl From<Double> for ScalarInt {
     #[inline]
     fn from(f: Double) -> Self {
         // We trust apfloat to give us properly truncated data.
-        Self { data: f.to_bits(), size: NonZeroU8::new((Double::BITS / 8) as u8).unwrap() }
+        Self { data: f.to_bits(), size: NonZero::<u8>::new((Double::BITS / 8) as u8).unwrap() }
     }
 }
 

compiler/rustc_middle/src/ty/generic_args.rs

@@ -18,7 +18,7 @@ use core::intrinsics;
 use std::cmp::Ordering;
 use std::marker::PhantomData;
 use std::mem;
-use std::num::NonZeroUsize;
+use std::num::NonZero;
 use std::ops::{ControlFlow, Deref};
 use std::ptr::NonNull;
 
@@ -144,7 +144,7 @@ impl<'tcx> GenericArg<'tcx> {
     #[inline]
     pub fn unpack(self) -> GenericArgKind<'tcx> {
         let ptr = unsafe {
-            self.ptr.map_addr(|addr| NonZeroUsize::new_unchecked(addr.get() & !TAG_MASK))
+            self.ptr.map_addr(|addr| NonZero::<usize>::new_unchecked(addr.get() & !TAG_MASK))
         };
         // SAFETY: use of `Interned::new_unchecked` here is ok because these
         // pointers were originally created from `Interned` types in `pack()`,

compiler/rustc_middle/src/ty/layout.rs

@@ -20,7 +20,7 @@ use rustc_target::spec::{abi::Abi as SpecAbi, HasTargetSpec, PanicStrategy, Targ
 
 use std::cmp;
 use std::fmt;
-use std::num::NonZeroUsize;
+use std::num::NonZero;
 use std::ops::Bound;
 
 pub trait IntegerExt {
@@ -761,7 +761,7 @@ where
                 };
                 tcx.mk_layout(LayoutS {
                     variants: Variants::Single { index: variant_index },
-                    fields: match NonZeroUsize::new(fields) {
+                    fields: match NonZero::<usize>::new(fields) {
                         Some(fields) => FieldsShape::Union(fields),
                         None => FieldsShape::Arbitrary { offsets: IndexVec::new(), memory_index: IndexVec::new() },
                     },

compiler/rustc_middle/src/ty/mod.rs

@@ -61,7 +61,7 @@ use std::fmt::Debug;
 use std::hash::{Hash, Hasher};
 use std::marker::PhantomData;
 use std::mem;
-use std::num::NonZeroUsize;
+use std::num::NonZero;
 use std::ops::ControlFlow;
 use std::ptr::NonNull;
 use std::{fmt, str};
@@ -618,7 +618,7 @@ impl<'tcx> Term<'tcx> {
     #[inline]
     pub fn unpack(self) -> TermKind<'tcx> {
         let ptr = unsafe {
-            self.ptr.map_addr(|addr| NonZeroUsize::new_unchecked(addr.get() & !TAG_MASK))
+            self.ptr.map_addr(|addr| NonZero::<usize>::new_unchecked(addr.get() & !TAG_MASK))
         };
         // SAFETY: use of `Interned::new_unchecked` here is ok because these
         // pointers were originally created from `Interned` types in `pack()`,

compiler/rustc_passes/src/lib.rs

@@ -8,6 +8,7 @@
 #![doc(rust_logo)]
 #![feature(rustdoc_internals)]
 #![allow(internal_features)]
+#![feature(generic_nonzero)]
 #![feature(let_chains)]
 #![feature(map_try_insert)]
 #![feature(try_blocks)]

compiler/rustc_passes/src/stability.rs

@@ -27,7 +27,7 @@ use rustc_span::Span;
 use rustc_target::spec::abi::Abi;
 
 use std::mem::replace;
-use std::num::NonZeroU32;
+use std::num::NonZero;
 
 #[derive(PartialEq)]
 enum AnnotationKind {
@@ -645,7 +645,7 @@ fn stability_index(tcx: TyCtxt<'_>, (): ()) -> Index {
             let stability = Stability {
                 level: attr::StabilityLevel::Unstable {
                     reason: UnstableReason::Default,
-                    issue: NonZeroU32::new(27812),
+                    issue: NonZero::<u32>::new(27812),
                     is_soft: false,
                     implied_by: None,
                 },

compiler/rustc_query_impl/src/lib.rs

@@ -3,6 +3,7 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]
 #![feature(rustdoc_internals)]
+#![feature(generic_nonzero)]
 #![feature(min_specialization)]
 #![feature(rustc_attrs)]
 #![allow(rustc::potential_query_instability, unused_parens)]

compiler/rustc_query_impl/src/plumbing.rs

@@ -30,7 +30,7 @@ use rustc_serialize::Decodable;
 use rustc_serialize::Encodable;
 use rustc_session::Limit;
 use rustc_span::def_id::LOCAL_CRATE;
-use std::num::NonZeroU64;
+use std::num::NonZero;
 use thin_vec::ThinVec;
 
 #[derive(Copy, Clone)]
@@ -68,7 +68,7 @@ impl QueryContext for QueryCtxt<'_> {
     #[inline]
     fn next_job_id(self) -> QueryJobId {
         QueryJobId(
-            NonZeroU64::new(
+            NonZero::<u64>::new(
                 self.query_system.jobs.fetch_add(1, std::sync::atomic::Ordering::Relaxed),
             )
             .unwrap(),

compiler/rustc_query_system/src/lib.rs

@@ -1,5 +1,6 @@
 #![feature(assert_matches)]
 #![feature(core_intrinsics)]
+#![feature(generic_nonzero)]
 #![feature(hash_raw_entry)]
 #![feature(min_specialization)]
 #![feature(let_chains)]

compiler/rustc_query_system/src/query/job.rs

@@ -11,7 +11,7 @@ use rustc_span::Span;
 
 use std::hash::Hash;
 use std::io::Write;
-use std::num::NonZeroU64;
+use std::num::NonZero;
 
 #[cfg(parallel_compiler)]
 use {
@@ -36,7 +36,7 @@ pub type QueryMap = FxHashMap<QueryJobId, QueryJobInfo>;
 
 /// A value uniquely identifying an active query job.
 #[derive(Copy, Clone, Eq, PartialEq, Hash, Debug)]
-pub struct QueryJobId(pub NonZeroU64);
+pub struct QueryJobId(pub NonZero<u64>);
 
 impl QueryJobId {
     fn query(self, map: &QueryMap) -> QueryStackFrame {

compiler/rustc_serialize/src/lib.rs

@@ -11,6 +11,7 @@
 #![feature(associated_type_bounds)]
 #![feature(const_option)]
 #![feature(core_intrinsics)]
+#![feature(generic_nonzero)]
 #![feature(inline_const)]
 #![feature(min_specialization)]
 #![feature(never_type)]

compiler/rustc_serialize/src/serialize.rs

@@ -6,6 +6,7 @@ use std::cell::{Cell, RefCell};
 use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet, VecDeque};
 use std::hash::{BuildHasher, Hash};
 use std::marker::PhantomData;
+use std::num::NonZero;
 use std::path;
 use std::rc::Rc;
 use std::sync::Arc;
@@ -216,15 +217,15 @@ impl<D: Decoder> Decodable<D> for ! {
     }
 }
 
-impl<S: Encoder> Encodable<S> for ::std::num::NonZeroU32 {
+impl<S: Encoder> Encodable<S> for NonZero<u32> {
     fn encode(&self, s: &mut S) {
         s.emit_u32(self.get());
     }
 }
 
-impl<D: Decoder> Decodable<D> for ::std::num::NonZeroU32 {
+impl<D: Decoder> Decodable<D> for NonZero<u32> {
     fn decode(d: &mut D) -> Self {
-        ::std::num::NonZeroU32::new(d.read_u32()).unwrap()
+        NonZero::<u32>::new(d.read_u32()).unwrap()
     }
 }
 

compiler/rustc_session/src/config.rs

@@ -3226,7 +3226,7 @@ pub(crate) mod dep_tracking {
     };
     use std::collections::BTreeMap;
     use std::hash::{DefaultHasher, Hash};
-    use std::num::NonZeroUsize;
+    use std::num::NonZero;
     use std::path::PathBuf;
 
     pub trait DepTrackingHash {
@@ -3268,7 +3268,7 @@ pub(crate) mod dep_tracking {
     impl_dep_tracking_hash_via_hash!(
         bool,
         usize,
-        NonZeroUsize,
+        NonZero<usize>,
         u64,
         Hash64,
         String,

compiler/rustc_session/src/errors.rs

@@ -1,4 +1,4 @@
-use std::num::NonZeroU32;
+use std::num::NonZero;
 
 use rustc_ast::token;
 use rustc_ast::util::literal::LitError;
@@ -26,7 +26,7 @@ impl<'a> IntoDiagnostic<'a> for FeatureGateError {
 #[derive(Subdiagnostic)]
 #[note(session_feature_diagnostic_for_issue)]
 pub struct FeatureDiagnosticForIssue {
-    pub n: NonZeroU32,
+    pub n: NonZero<u32>,
 }
 
 #[derive(Subdiagnostic)]

compiler/rustc_session/src/lib.rs

@@ -1,3 +1,4 @@
+#![feature(generic_nonzero)]
 #![feature(let_chains)]
 #![feature(lazy_cell)]
 #![feature(option_get_or_insert_default)]

compiler/rustc_session/src/options.rs

@@ -21,7 +21,7 @@ use rustc_span::SourceFileHashAlgorithm;
 use std::collections::BTreeMap;
 
 use std::hash::{DefaultHasher, Hasher};
-use std::num::{IntErrorKind, NonZeroUsize};
+use std::num::{IntErrorKind, NonZero};
 use std::path::PathBuf;
 use std::str;
 
@@ -617,7 +617,7 @@ mod parse {
     pub(crate) fn parse_threads(slot: &mut usize, v: Option<&str>) -> bool {
         match v.and_then(|s| s.parse().ok()) {
             Some(0) => {
-                *slot = std::thread::available_parallelism().map_or(1, std::num::NonZeroUsize::get);
+                *slot = std::thread::available_parallelism().map_or(1, NonZero::<usize>::get);
                 true
             }
             Some(i) => {
@@ -991,7 +991,10 @@ mod parse {
         true
     }
 
-    pub(crate) fn parse_treat_err_as_bug(slot: &mut Option<NonZeroUsize>, v: Option<&str>) -> bool {
+    pub(crate) fn parse_treat_err_as_bug(
+        slot: &mut Option<NonZero<usize>>,
+        v: Option<&str>,
+    ) -> bool {
         match v {
             Some(s) => match s.parse() {
                 Ok(val) => {
@@ -1004,7 +1007,7 @@ mod parse {
                 }
             },
             None => {
-                *slot = NonZeroUsize::new(1);
+                *slot = NonZero::<usize>::new(1);
                 true
             }
         }
@@ -1950,7 +1953,7 @@ written to standard error output)"),
         "translate remapped paths into local paths when possible (default: yes)"),
     trap_unreachable: Option<bool> = (None, parse_opt_bool, [TRACKED],
         "generate trap instructions for unreachable intrinsics (default: use target setting, usually yes)"),
-    treat_err_as_bug: Option<NonZeroUsize> = (None, parse_treat_err_as_bug, [TRACKED],
+    treat_err_as_bug: Option<NonZero<usize>> = (None, parse_treat_err_as_bug, [TRACKED],
         "treat the `val`th error that occurs as bug (default if not specified: 0 - don't treat errors as bugs. \
         default if specified without a value: 1 - treat the first error as bug)"),
     trim_diagnostic_paths: bool = (true, parse_bool, [UNTRACKED],