Highlight lint bug.

Author: reitermarkus

compiler/rustc_lint/src/types.rs

@@ -1056,7 +1056,7 @@ fn get_nullable_type<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Option<Ty<'tcx>>
 
 /// Check if this enum can be safely exported based on the "nullable pointer optimization". If it
 /// can, return the type that `ty` can be safely converted to, otherwise return `None`.
-/// Currently restricted to function pointers, boxes, references, `core::num::NonZero*`,
+/// Currently restricted to function pointers, boxes, references, `core::num::NonZero`,
 /// `core::ptr::NonNull`, and `#[repr(transparent)]` newtypes.
 /// FIXME: This duplicates code in codegen.
 pub(crate) fn repr_nullable_ptr<'tcx>(
@@ -1102,7 +1102,13 @@ pub(crate) fn repr_nullable_ptr<'tcx>(
                     return Some(get_nullable_type(tcx, field_ty).unwrap());
                 }
                 WrappingRange { start: 1, .. } => {
-                    return Some(get_nullable_type(tcx, field_ty).unwrap());
+                    let nullable_type = get_nullable_type(tcx, field_ty);
+
+                    if nullable_type.is_none() {
+                        bug!("cannot get nullable type for field_ty {field_ty:?}");
+                    }
+
+                    return Some(nullable_type.unwrap());
                 }
                 WrappingRange { start, end } => {
                     unreachable!("Unhandled start and end range: ({}, {})", start, end)

library/core/src/num/nonzero.rs

@@ -103,6 +103,7 @@ impl_zeroable_primitive!(
 /// ```
 #[unstable(feature = "generic_nonzero", issue = "120257")]
 #[repr(transparent)]
+#[rustc_nonnull_optimization_guaranteed]
 #[rustc_diagnostic_item = "NonZero"]
 pub struct NonZero<T: ZeroablePrimitive>(T::NonZeroInner);