syntax_data: {"ast_node_type":"impl","tokens":[{"end":92,"kind":"keyword","start":0,"text":"push_cuta:"}]}
source_snippet:     push_cuta: impl FnMut(&Box<CanonicalUserType<'tcx>>) -> Option<UserTypeAnnotationIndex>,
context_before:     expr: &Expr<'tcx>,
context_after:     tcx: TyCtxt<'tcx>,