{"ast_node_type":"other","tokens":[{"end":57,"kind":"keyword","start":0,"text":"mapped_types:"}]}
    mapped_types: IndexMap<I::PlaceholderTy, I::BoundTy>,
    mapped_regions: IndexMap<I::PlaceholderRegion, I::BoundRegion>,
    mapped_consts: IndexMap<I::PlaceholderConst, I::BoundConst>,