syntax_data: {"ast_node_type":"other","tokens":[{"end":99,"kind":"keyword","start":0,"text":"field_types:"}]}
source_snippet:                                     field_types: self.typeck_results.fru_field_types()[expr.hir_id]
context_before:                                     base: self.mirror_expr(base),
context_after:                                         .iter()