syntax_data: {"ast_node_type":"other","tokens":[{"end":82,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:             // If the type of the item uses `_`, we're gonna error out anyway, but
context_before:             let hir_sig = tcx.hir_node_by_def_id(item).fn_decl().unwrap();
context_after:             // typeck (which type_of invokes below), will call back into opaque_types_defined_by