Option field causes C error when struct embeds multiple other structs

[islonely]

Describe the bug

When struct A embeds struct B and struct C (which has an option field) and struct A is cast to interface A, then comparing the interface A with another interface A will cause a C error.

Reproduction Steps

fn main() {
	mut arr := []&NodeInterface{}
	arr << &HTMLElement{}
	arr << &HTMLElement{}

	// removing this comparison lets the code compile
	println(arr[0] == arr[1])
}

pub interface Element {
	NodeInterface
mut:
	tag_name string
}

pub interface NodeInterface {
mut:
	node_name string
}

pub struct Node {
pub mut:
	node_name string
}

pub struct HTMLElement {
	Node
pub mut:
	tag_name string
}

pub struct HTMLInputElement {
	// removing either one of these embedded structs lets the code compile
	HTMLElement
	PopoverInvokerElement
pub mut:
	value string
}

pub struct PopoverInvokerElement {
pub mut:
	// changing this field to `&Element` lets the code compile
	popover_target_element ?&Element
	popover_target_action  string
}

Expected Behavior

Expected code to compile and print true or false

Current Behavior

C:/Users/imado/AppData/Local/Temp/v_0/test.10654267466622163022.tmp.c:510: warning: WINVER redefined
C:/Users/imado/AppData/Local/Temp/v_0/test.10654267466622163022.tmp.c:2319: error: expected struct or union but not 'struct main__Element *'
builder error: 
==================
C error. This should never happen.

Possible Solution

No response

Additional Information/Context

No response

V version

V full version: V 0.4.1 68cbf27.20bce37

Environment details (OS name and version, etc.)

V full version: V 0.4.1 68cbf27.20bce37
OS: windows, Microsoft Windows 11 Pro v22621 64-bit
Processor: 16 cpus, 64bit, little endian, 

getwd: C:\Users\imado\Documents\cyberian_tiger
vexe: C:\Users\imado\v\v.exe
vexe mtime: 2023-09-25 15:32:08

vroot: OK, value: C:\Users\imado\v
VMODULES: OK, value: C:\Users\imado\.vmodules
VTMP: OK, value: C:\Users\imado\AppData\Local\Temp\v_0

Git version: git version 2.33.1.windows.1
Git vroot status: weekly.2023.38-38-g20bce37d
.git/config present: true

CC version: Error: 'cc' is not recognized as an internal or external command,
operable program or batch file.

thirdparty/tcc status: thirdparty-windows-amd64 e90c2620

Important

You can vote for this issue using the 👍 reaction. More votes increase the issue's priority
for developers.

Take into account that only the 👍 reaction counts as a vote.
Only reactions to the issue itself will be counted as votes, not comments.

[yuyi98]

[]&NodeInterface{}
Why do interfaces need to use references? Just []NodeInterface{} is ok.

fn main() {
	mut arr := []NodeInterface{}
	arr << &HTMLElement{}
	arr << &HTMLElement{}

	// removing this comparison lets the code compile
	println(arr[0] == arr[1])
}

pub interface Element {
	NodeInterface
mut:
	tag_name string
}

pub interface NodeInterface {
mut:
	node_name string
}

pub struct Node {
pub mut:
	node_name string
}

pub struct HTMLElement {
	Node
pub mut:
	tag_name string
}

pub struct HTMLInputElement {
	// removing either one of these embedded structs lets the code compile
	HTMLElement
	PopoverInvokerElement
pub mut:
	value string
}

pub struct PopoverInvokerElement {
pub mut:
	// changing this field to `&Element` lets the code compile
	popover_target_element ?Element
	popover_target_action  string
}

PS D:\Test\v\tt1> v run .
false

[islonely]

Because I wanted to make sure the underlying type is passed by reference and not value. Sorry if that's not right. I have a background of primarily Java and JavaScript where everything is references.

[islonely]

The way you have it I can't cast back to the original type. Changing your main fn, this println is not allowed,

fn main() {
	mut arr := []NodeInterface{}
	arr << &HTMLElement{}
	arr << &HTMLElement{}

	println(HTMLElement(arr[0]))
}

But this is.

fn main() {
	mut arr := []&NodeInterface{}
	arr << &HTMLElement{}
	arr << &HTMLElement{}

	println(&HTMLElement(arr[0]))
}