syntax_data: {"ast_node_type":"function","tokens":[{"end":78,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn struct_tail_ty(self, interner: I) -> Option<ty::EarlyBinder<I, I::Ty>>;
context_before:     /// Expects the `AdtDef` to be a struct. If it is not, then this will panic.