pass.Report(diag)
	})
	return nil, nil
}

func structuralTypes(t types.Type) ([]types.Type, error) {
	var structuralTypes []types.Type
	if tp, ok := aliases.Unalias(t).(*types.TypeParam); ok {
		terms, err := typeparams.StructuralTerms(tp)
		if err != nil {
			return nil, err
		}
		for _, term := range terms {
			structuralTypes = append(structuralTypes, term.Type())
		}
	} else {

	if t == nil {
		return
	}
	var structuralTypes []types.Type
	switch t := aliases.Unalias(t).(type) {
	case *types.TypeParam:
		terms, err := typeparams.StructuralTerms(t)
		if err != nil {
			return // invalid type
		}
		for _, term := range terms {
			structuralTypes = append(structuralTypes, term.Type())
		}
	default:
		structuralTypes = append(structuralTypes, t)
	}
	sizes := make(map[int64]struct{})

			return
		}
		var structuralTypes []types.Type
		switch typ := aliases.Unalias(typ).(type) {
		case *types.TypeParam:
			terms, err := typeparams.StructuralTerms(typ)
			if err != nil {
				return // invalid type
			}
			for _, term := range terms {
				structuralTypes = append(structuralTypes, term.Type())
			}
		default:
			structuralTypes = append(structuralTypes, typ)
		}