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