Unable to correctly get pointer for "struct System.Nullable<T> : System.ValueType"?

[wildsheepz]

Hi I am facing some issue trying to interact with System.Nullable
Here is the code I am using:

var object = new Il2Cpp.Object(this.instance)
console.log('ClassName: ', object.class.name)

const SystemNullable_class = corlibclasses['System.Nullable<T>']
const SystemNullable_CoroutineHandle_class = SystemNullable_class.inflate(CoroutineHandle_class)
const SystemNullable_CoroutineHandle_field_value = SystemNullable_CoroutineHandle_class.fields['value']
const SystemNullable_CoroutineHandle_field_has_value = SystemNullable_CoroutineHandle_class.fields['has_value']

const SystemNullable_CoroutineHandle_get_Value = SystemNullable_CoroutineHandle_class.methods['get_Value']
const SystemNullable_CoroutineHandle_get_Value_func = new NativeFunction(SystemNullable_CoroutineHandle_get_Value.virtualAddress, 'pointer', ['pointer'])
const SystemNullable_CoroutineHandle_get_HasValue = SystemNullable_CoroutineHandle_class.methods['get_HasValue']
const SystemNullable_CoroutineHandle_get_HasValue_func = new NativeFunction(SystemNullable_CoroutineHandle_get_HasValue.virtualAddress, 'bool', ['pointer'])

// System.Nullable<MEC.CoroutineHandle> TransitionHandle; // 0x104
var nullable_transitionhandle = this.instance.add(0x104).readPointer()
console.log('nullable_transitionhandle', nullable_transitionhandle)
console.log('nullable_transitionhandle hasValue()', SystemNullable_CoroutineHandle_get_HasValue_func(nullable_transitionhandle))

Output and error I received:

PanelQuestData
nullable_transitionhandle 0x100070431
Error: access violation accessing 0x100070439
    at onLeave (test.ts:476)

[vfsfitvnm]

Hi, a question first:
Why are you using NativeFunctions?
...
System.Nullable<T> is a value type (a c# struct), hence not a object (0x100070431 is not a virtual address).

var nullable_transitionhandle = this.instance.add(0x104).readPointer()

That's not how you read a System.ValueType value (remove readPointer())

SystemNullable_CoroutineHandle_get_HasValue_func(nullable_transitionhandle)

You can't call a method on a struct. You must convert it to a object (aka boxing) first.

However, all these things are correctly handled by frida-il2cpp-bridge, but you are not using it

[wildsheepz]

However, all these things are correctly handled by frida-il2cpp-bridge, but you are not using it

Thanks for the help, I understand where I did wrong now.
I was too used to the old frida way using nativepointer, I should be using the bridge instead.

The following works:

var nullable_transitionhandle = new Il2Cpp.ValueType(this.instance.add(PanelQuestData_TransitionHandle.offset), SystemNullable_CoroutineHandle_class.type)

[vfsfitvnm]

@wildsheepz
This is even better:

const object = new Il2Cpp.Object(this.instance);
const nullable_transitionhandle = object.fields.TransitionHandle.value as Il2Cpp.ValueType;

[etmltg69]

@vfsfitvnm
How do I create a Nullable? If i create a new instance, I always get int only