syntax_data: {"ast_node_type":"variable","tokens":[{"end":24,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let callee_sig =
context_before:         // Erase regions since tail calls don't care about lifetimes
context_after:             self.tcx.normalize_erasing_late_bound_regions(self.typing_env, ty.fn_sig(self.tcx));