syntax_data: {"ast_node_type":"other","tokens":[{"end":38,"kind":"keyword","start":0,"text":"param_env:"}]}
source_snippet:         param_env: ty::ParamEnv<'tcx>,
context_before:         recursion_depth: usize,
context_after:         parent_trait_pred: ty::Binder<'tcx, ty::TraitPredicate<'tcx>>,