Function arguments

pub fn arguments<'a, 'b>(
    tcx: TyCtxt<'_>,
    hir_id: HirId,
    attr_span: Span,
) -> impl Parser<I<'b>, TinyBitSet, ErrorTree<I<'b>>> + use<'a, 'b, '_>

Parse the arguments refinement.

Note that the body argument isn’t actually always a trait function. The Provided variant is (in this case) also used for normal functions.