{"ast_node_type":"other","tokens":[{"end":57,"kind":"keyword","start":0,"text":"const_substs:"}]}
    const_substs: FxHashMap<hir::ConstParam, SyntaxNode>,
    type_substs: FxHashMap<hir::TypeParam, ast::Type>,
    lifetime_substs: FxHashMap<LifetimeName, ast::Lifetime>,