### Trouble defining polynomial ring over Gaussian integers

Hello,

I would like to define a polynomial ring over `ZZ[I]`

, e.g. like this:

```
sage: R.<x> = PolynomialRing(ZZ[I])
```

If I run this on sage 9.4 I get the following:

```
sage: R
Univariate Polynomial Ring in x over Order in Number Field in I0 with defining polynomial x^2 + 1 with I0 = 1*I
```

If I now try to define a polynomial with complex coefficients I get:

```
sage: f = I*x
TypeError: unsupported operand parent(s) for *: 'Number Field in I with defining polynomial x^2 + 1 with I = 1*I' and 'Univariate Polynomial Ring in x over Order in Number Field in I0 with defining polynomial x^2 + 1 with I0 = 1*I'
```

On SageMath version 9.0 I do not get the same error. Instead it says:

```
sage: R
Univariate Polynomial Ring in x over Order in Number Field in I with defining polynomial x^2 + 1 with I = 1*I
```

and i have no issues defining `f = I*x`

. How do I resolve this issue in SageMath version 9.4?

Edit: I have done some further investigation, and the problem lies with this `I0`

in

```
sage: ZZ[I]
Order in Number Field in I0 with defining polynomial x^2 + 1 with I0 = 1*I
```

What is the difference between `I0`

and `I`

and how do I work with it? Simply typing `f = I0 * x`

also results in an ~~error.~~error. Is this maybe a bug in SageMath 9.4? Does the same happen in SageMath 9.5?