syntax_data: {"ast_node_type":"variable","tokens":[{"end":31,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let mut impl_def_id = None;
context_before:     let mut structural_peq = false;
context_after:     for def_id in tcx.non_blanket_impls_for_ty(partial_eq_trait_id, ty) {