json encode double fixed array

[jorgeluismireles]

Describe the bug

Code: https://play.vlang.io/p/cae76f07e6

import json

struct Base {
	options  Options
	profiles Profiles
}

struct Options {
	cfg [6]u8
}

struct Profiles {
	cfg [4][7]u8 // <- cause of C error
}

fn main() {
	println(Base{}) // OK
	println(json.encode(Base{})) // C error
}

Reproduction Steps

Run the code at the playground

Expected Behavior

Create json string from the object. Regular print is

Base{
    options: Options{
        cfg: [0, 0, 0, 0, 0, 0]
    }
    profiles: Profiles{
        cfg: [[0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0]]
    }
}

Current Behavior

Output:

/tmp/v_60000/code.01J923657XT1ASJX52P6NTVDTT.tmp.c:2610: error: '{' expected (got ";")
builder error: 
==================
C error found. It should never happen, when compiling pure V code.
This is a V compiler bug, please report it using `v bug file.v`,
or goto https://github.com/vlang/v/issues/new/choose .
You can also use #help on Discord: https://discord.gg/vlang .
Exited with error status 1

Possible Solution

No response

Additional Information/Context

No response

V version

V 0.4.8 aa3ab3f

Environment details (OS name and version, etc.)

V full version: V 0.4.8 aa3ab3f
OS: linux, Debian GNU/Linux 12 (bookworm) (VM)
Processor: 2 cpus, 64bit, little endian, Intel(R) Xeon(R) CPU E5-2680 v4 @ 2.40GHz

getwd: /home/admin/playground
vexe: /home/admin/v/v
vexe mtime: 2024-09-30 18:25:27

vroot: OK, value: /home/admin/v
VMODULES: OK, value: .vmodules
VTMP: OK, value: /tmp/v_0

Git version: git version 2.39.5
Git vroot status: Error: fatal: detected dubious ownership in repository at '/home/admin/v'
To add an exception for this directory, call:

	git config --global --add safe.directory /home/admin/v
.git/config present: true

CC version: cc (Debian 12.2.0-14) 12.2.0
thirdparty/tcc status: Error: fatal: detected dubious ownership in repository at '/home/admin/v/thirdparty/tcc'
To add an exception for this directory, call:

	git config --global --add safe.directory /home/admin/v/thirdparty/tcc
 Error: fatal: detected dubious ownership in repository at '/home/admin/v/thirdparty/tcc'
To add an exception for this directory, call:

	git config --global --add safe.directory /home/admin/v/thirdparty/tcc

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[jorgeluismireles]

I didn't remember was reported already: #22363

[jorgeluismireles]

Trying with x.json2 and setting everything pub mut gives another error:

import x.json2

pub struct Base {
pub mut:
	options  Options
	profiles Profiles
}

pub struct Options {
pub mut:
	cfg [6]u8
}

pub struct Profiles {
pub mut:
	cfg [4][7]u8
}

fn main() {
	println(json2.encode(Base{}))
}

/home/jorge/v/vlib/x/json2/encoder.v:313:8: error: could not infer generic type `U` in call to `encode_array`
  311 |                 } $else $if field.is_array {
  312 |                     // TODO: replace for `field.typ is $array`
  313 |                     e.encode_array(value, level + 1, mut buf)!
      |                       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  314 |                 } $else $if field.typ is $array {
  315 |                     // e.encode_array(value, level + 1, mut buf)! // FIXME: error: could not infer generic type `U` in call to `encode_array`

[esquerbatua]

I didn't remember was reported already: #22363

seems that it's not related