{"ast_node_type":"other","tokens":[{"end":60,"kind":"keyword","start":0,"text":"#[cfg_attr(feature"}]}
#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
#[derive(PartialEq, Eq, Hash, Clone)]
pub struct LayoutData<FieldIdx: Idx, VariantIdx: Idx> {