syntax_data: {"ast_node_type":"variable","tokens":[{"end":77,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:             let ty = if fn_decl.c_variadic && index == fn_decl.inputs.len() {
context_before:             // (as it's created inside the body itself, not passed in from outside).
context_after:                 let va_list_did = self.tcx.require_lang_item(LangItem::VaList, param.span);