optional sumtype struct field builder error #20181

Describe the bug

This code

import json

type Prices = []Price | Price

pub struct ShopResponseData {
    attributes Attributes
}

struct Attributes {
    price ?Prices
}

struct Price {
    net f64
}

fn main() {
    data := '{"attributes": {"price": [{"net": 1}, {"net": 2}]}}'
    entity := json.decode(ShopResponseData, data) or { panic(err) }

    data2 := '{"attributes": {"price": {"net": 1}}}'
    entity2 := json.decode(ShopResponseData, data2) or { panic(err) }

    println(entity)
    println(entity2)
}

Gives this compiler error:
/tmp/v_1000/1.1463261147480528181.tmp.c:2389: error: cannot convert 'struct main__Prices' to 'struct _option_main__Prices'

Reproduction Steps

Use the code from above and v run .

Expected Behavior

successful compilation

Current Behavior

builder error:

v -cg run 1.v
/tmp/v_1000/1.17748602982829807624.tmp.c:2391: error: cannot convert 'struct main__Prices' to 'struct _option_main__Prices'
builder error: 
==================
C error. This should never happen.

Possible Solution

No response

Additional Information/Context

Code was suggested on Discord https://discord.com/channels/592103645835821068/592294828432424960/1184889411259859084

V version

V 0.4.3 c5a6aeb

Environment details (OS name and version, etc.)

V full version: V 0.4.3 25777bd.c5a6aeb
OS: linux, Pop!_OS 22.04 LTS
Processor: 8 cpus, 64bit, little endian, Intel(R) Core(TM) i5-8305G CPU @ 2.80GHz

getwd: /home/loguser002/a/obereapotheke-import
vexe: /home/loguser002/a/v/v
vexe mtime: 2023-12-15 06:50:31

vroot: OK, value: /home/loguser002/a/v
VMODULES: OK, value: /home/loguser002/.vmodules
VTMP: OK, value: /tmp/v_1000

Git version: git version 2.34.1
Git vroot status: weekly.2023.50-29-gc5a6aebc
.git/config present: true

CC version: cc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0
thirdparty/tcc status: thirdparty-linux-amd64 12f392c3