'(Str|Undef)|(ArrayRef|HashRef) is not a type of Str'
);
+type 'SomeType', where { 1 };
+type 'OtherType', where { 1 };
+
+my $parentless_union = Moose::Meta::TypeConstraint::Union->new(
+ type_constraints => [
+ find_type_constraint('SomeType'),
+ find_type_constraint('OtherType'),
+ ],
+);
+
+is($parentless_union->parent, undef, "no common ancestor gives undef parent");
+
+
done_testing;