1 use rustc_errors::struct_span_err;
2 use rustc_middle::ty::TyCtxt;
3 use rustc_span::symbol::sym;
5 pub fn test_variance(tcx: TyCtxt<'_>) {
6 // For unit testing: check for a special "rustc_variance"
7 // attribute and report an error with various results if found.
8 for id in tcx.hir().items() {
9 if tcx.has_attr(id.owner_id.to_def_id(), sym::rustc_variance) {
10 let variances_of = tcx.variances_of(id.owner_id);
11 struct_span_err!(tcx.sess, tcx.def_span(id.owner_id), E0208, "{:?}", variances_of)