syntax_data: {"ast_node_type":"other","tokens":[{"end":28,"kind":"keyword","start":0,"text":"tcx,"}]}
source_snippet:                         tcx,
context_before:                     let args = ty::GenericArgs::identity_for_item(tcx, def_id).rebase_onto(
context_after:                         impl_def_id.to_def_id(),