Coercing a pointer into an option uses the address as if it were a value

[spiveeworks]

Describe the bug

If a function expects an optional struct, but you pass it a pointer instead, it wraps the pointer itself instead of giving a type error or dereferencing the pointer.

Reproduction Steps

struct MyStruct {
x int
}

fn unwrap_option(event_data ?MyStruct) int {
if val := event_data {
return val.x
} else {
return 0
}
}

fn wrap_unwrap_ptr(
event_data &MyStruct
) int {
return unwrap_option(event_data)
}

fn main() {
data := MyStruct { x: 0 }
result := wrap_unwrap_ptr(&data)
assert data.x == result
}

Expected Behavior

Either a type error or for the assertion to pass.

Current Behavior

The code compiles but then the assertion fails. E.g.

option_ptr_bug.v:23: FAIL: fn main.main: assert data.x == result
left value: data.x = 0
right value: result = 645921536

This is the C code it generates:

VV_LOCAL_SYMBOL int main__wrap_unwrap_ptr(main__MyStruct* event_data) {
	_option_main__MyStruct _t2;
	_option_ok(&(main__MyStruct[]) { event_data }, (_option*)(&_t2), sizeof(main__MyStruct));
	int _t1 = main__unwrap_option( _t2);
	return _t1;
}

Notice event_data is a pointer, but it's used as the content of the option.

Possible Solution

Detecting this case and dereference the pointer, or giving a type error if this isn't meant to be allowed at all.

Additional Information/Context

No response

V version

V full version: V 0.4.5 386bd77.29e5124

Environment details (OS name and version, etc.)

V full version: V 0.4.5 386bd77.29e5124
OS: windows, Microsoft Windows 10 Pro v19045 64-bit
Processor: 4 cpus, 64bit, little endian,

getwd: C:\Users\Owner\Code\v-experiments
vexe: C:\Program Files\v\v.exe
vexe mtime: 2024-03-23 10:18:34

vroot: contains spaces, value: C:\Program Files\v
VMODULES: OK, value: C:\Users\Owner.vmodules
VTMP: OK, value: C:\Users\Owner\AppData\Local\Temp\v_0

Git version: git version 2.37.2.windows.2
Git vroot status: weekly.2024.11-67-g29e5124c
.git/config present: true

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

thirdparty/tcc: N/A

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