Rollup merge of #124587 - reitermarkus:use-generic-nonzero, r=dtolnay

Generic `NonZero` post-stabilization changes.

Tracking issue: #120257

r? ``@dtolnay``

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;
 
@@ -1149,7 +1149,7 @@ 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/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -2227,15 +2227,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     ) -> bool {
         let tcx = self.tcx;
         let (adt, args, unwrap) = match expected.kind() {
-            // In case Option<NonZero*> is wanted, but * is provided, suggest calling new
+            // In case `Option<NonZero<T>>` is wanted, but `T` is provided, suggest calling `new`.
             ty::Adt(adt, args) if tcx.is_diagnostic_item(sym::Option, adt.did()) => {
                 let nonzero_type = args.type_at(0); // Unwrap option type.
                 let ty::Adt(adt, args) = nonzero_type.kind() else {
                     return false;
                 };
                 (adt, args, "")
             }
-            // In case `NonZero<*>` is wanted but `*` is provided, also add `.unwrap()` to satisfy types.
+            // In case `NonZero<T>` is wanted but `T` is provided, also add `.unwrap()` to satisfy types.
             ty::Adt(adt, args) => (adt, args, ".unwrap()"),
             _ => return false,
         };
@@ -2244,32 +2244,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             return false;
         }
 
-        // FIXME: This can be simplified once `NonZero<T>` is stable.
-        let coercable_types = [
-            ("NonZeroU8", tcx.types.u8),
-            ("NonZeroU16", tcx.types.u16),
-            ("NonZeroU32", tcx.types.u32),
-            ("NonZeroU64", tcx.types.u64),
-            ("NonZeroU128", tcx.types.u128),
-            ("NonZeroI8", tcx.types.i8),
-            ("NonZeroI16", tcx.types.i16),
-            ("NonZeroI32", tcx.types.i32),
-            ("NonZeroI64", tcx.types.i64),
-            ("NonZeroI128", tcx.types.i128),
-        ];
-
         let int_type = args.type_at(0);
-
-        let Some(nonzero_alias) = coercable_types.iter().find_map(|(nonzero_alias, t)| {
-            if *t == int_type && self.can_coerce(expr_ty, *t) { Some(nonzero_alias) } else { None }
-        }) else {
+        if !self.can_coerce(expr_ty, int_type) {
             return false;
-        };
+        }
 
         err.multipart_suggestion(
-            format!("consider calling `{nonzero_alias}::new`"),
+            format!("consider calling `{}::new`", sym::NonZero),
             vec![
-                (expr.span.shrink_to_lo(), format!("{nonzero_alias}::new(")),
+                (expr.span.shrink_to_lo(), format!("{}::new(", sym::NonZero)),
                 (expr.span.shrink_to_hi(), format!("){unwrap}")),
             ],
             Applicability::MaybeIncorrect,

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
         }