-pub fn impl_implied_bounds<'tcx>(
- tcx: TyCtxt<'tcx>,
- param_env: ty::ParamEnv<'tcx>,
- impl_def_id: LocalDefId,
- span: Span,
-) -> FxHashSet<Ty<'tcx>> {
- // We completely ignore any obligations caused by normalizing the types
- // we assume to be well formed. Considering that the user of the implied
- // bounds will also normalize them, we leave it to them to emit errors
- // which should result in better causes and spans.
- tcx.infer_ctxt().enter(|infcx| {
- let cause = ObligationCause::misc(span, tcx.hir().local_def_id_to_hir_id(impl_def_id));
- match tcx.impl_trait_ref(impl_def_id) {
- Some(trait_ref) => {
- // Trait impl: take implied bounds from all types that
- // appear in the trait reference.
- match infcx.at(&cause, param_env).normalize(trait_ref) {
- Ok(Normalized { value, obligations: _ }) => value.substs.types().collect(),
- Err(NoSolution) => FxHashSet::default(),
- }
- }
-
- None => {
- // Inherent impl: take implied bounds from the `self` type.
- let self_ty = tcx.type_of(impl_def_id);
- match infcx.at(&cause, param_env).normalize(self_ty) {
- Ok(Normalized { value, obligations: _ }) => FxHashSet::from_iter([value]),
- Err(NoSolution) => FxHashSet::default(),
- }
- }
- }
- })
-}
-