Struct and Reference Struct type mismatch in Struct Default Value

[heyimtcn]

Describe the bug

Note: Bar must at least have 1 field or it will be interpreted as nil and work

struct Foo {
	bar &Bar = Bar{}
}

struct Bar {
	field int
}

fn main() {
	dump(Foo{})
}

If type Foo.bar is &Bar but is provided Bar it will throw this C error:
/tmp/v_60000/../../../../../../box/code.v:10: error: cannot convert 'struct main__Bar' to 'struct main__Bar *'

If type Foo.bar is Bar but is provided &Bar it will convert &Bar to Bar but Bar's field values will be corrupted like #20969

Reproduction Steps

struct Foo {
	bar &Bar = Bar{}
}

struct Bar {
	field int
}

fn main() {
	dump(Foo{})
}

Expected Behavior

Proper serialisation of the default field values or V error

Current Behavior

If type Foo.bar is &Bar but is provided Bar it will throw this C error:
/tmp/v_60000/../../../../../../box/code.v:10: error: cannot convert 'struct main__Bar' to 'struct main__Bar *'

If type Foo.bar is Bar but is provided &Bar it will convert &Bar to Bar but Bar's field values will be corrupted like #20969

Possible Solution

Whilst default field values don't work, setting them at runtime does, so adding those checks at comptime for default field values might help

Additional Information/Context

Found and tested in V playground

V version

V 0.4.5 0e2b604

Environment details (OS name and version, etc.)

V full version: V 0.4.5 0e2b604
OS: linux, Debian GNU/Linux 11 (bullseye) (VM)
Processor: 1 cpus, 64bit, little endian, Intel(R) Xeon(R) CPU E5-2686 v4 @ 2.30GHz

getwd: /home/admin/playground
vexe: /home/admin/v/v
vexe mtime: 2024-05-11 08:25:23

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

Git version: git version 2.30.2
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 10.2.1-6) 10.2.1 20210110
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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