syntax_data: {"ast_node_type":"other","tokens":[{"end":68,"kind":"keyword","start":0,"text":"mapped_consts:"}]}
source_snippet:     mapped_consts: FxIndexMap<ty::PlaceholderConst, ty::BoundConst>,
context_before:     mapped_types: FxIndexMap<ty::PlaceholderType, ty::BoundTy>,
context_after:     universe_indices: &'a [Option<ty::UniverseIndex>],