syntax_data: {"ast_node_type":"variable","tokens":[{"end":60,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:             if let Some(i) = maybe_unsizing_param_idx(arg) {
context_before:         for arg in tcx.type_of(field.did).instantiate_identity().walk() {
context_after:                 unsizing_params.remove(i);