#[derive(PartialEq, Eq, Hash, Debug, HashStable_Generic)]
pub struct LayoutDetails {
- pub variants: Variants,
+ /// Says where the fields are located.
+ /// Primitives and fieldless enums appear as unions without fields.
pub fields: FieldPlacement,
+
+ /// Encodes information about multi-variant layouts.
+ /// Even with `Multiple` variants, a layout can still have fields! Those are then
+ /// shared between all variants. One of them will be the discriminant,
+ /// but e.g. generators can have more.
+ ///
+ /// A layout-guided recursive descent must first look at all the fields,
+ /// and only then check if this is a multi-variant layout and if so, proceed
+ /// with the active variant.
+ pub variants: Variants,
+
+ /// The `abi` defines how this data is passed between functions, and it defines
+ /// value restrictions via `valid_range`.
+ ///
+ /// Note that this is entirely orthogonal to the recursive structrue defined by
+ /// `variants` and `fields`; for example, `ManuallyDrop<Result<isize, isize>>` has
+ /// `Abi::ScalarPair`! So, having a non-`Aggregate` `abi` should not stop a recursive descent.
pub abi: Abi,
/// The leaf scalar with the largest number of invalid values