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clarify 'no fields'

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This commit is contained in:
Ralf Jung 2025-09-13 17:23:29 +02:00 • committed by Travis Cross
parent 29a19f84c2
commit 781432e355
2 changed files with 3 additions and 3 deletions
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4
compiler/rustc_lint/src/types.rs
View file

@ -814,7 +814,7 @@ fn get_nullable_type<'tcx>(
/// A type is niche-optimization candidate iff:
/// - Is a zero-sized type with alignment 1 (a “1-ZST”).
/// - Has no fields.
/// - Is either a struct/tuple with no fields, or an enum with no variants.
/// - Does not have the `#[non_exhaustive]` attribute.
fn is_niche_optimization_candidate<'tcx>(
tcx: TyCtxt<'tcx>,
@ -828,7 +828,7 @@ fn is_niche_optimization_candidate<'tcx>(
match ty.kind() {
ty::Adt(ty_def, _) => {
let non_exhaustive = ty_def.is_variant_list_non_exhaustive();
let empty = (ty_def.is_struct() && ty_def.all_fields().next().is_none())
let empty = (ty_def.is_struct() && ty_def.non_enum_variant().fields.is_empty())
|| (ty_def.is_enum() && ty_def.variants().is_empty());
!non_exhaustive && empty

2
library/core/src/result.rs
View file

@ -235,7 +235,7 @@
//! [representation guarantees][opt-rep] (let's call that type `I`), and the *other* type must meet
//! all of the following conditions:
//! * Is a zero-sized type with alignment 1 (a "1-ZST").
//! * Has no fields.
//! * Is either a struct/tuple with no fields, or an enum with no variants.
//! * Does not have the `#[non_exhaustive]` attribute.
//!
//! If that is the case, then `Result<T, E>` has the same size, alignment, and [function call ABI]