{"ast_node_type":"impl","tokens":[{"end":54,"kind":"keyword","start":0,"text":"in_module:"}]}
        in_module: &impl Fn(DefId) -> Result<bool, E>,
        eval_stack: &mut SmallVec<[Ty<'tcx>; 1]>, // for cycle detection
        reveal_opaque: &impl Fn(OpaqueTypeKey<'tcx>) -> Option<Ty<'tcx>>,