Why am I getting this Warning when using the new Level Blueprint Communication?


I’ve set up an empty test level in order to try out the new Level Blueprint communication (BP Interfaces). It consists of a Persistent Level and two Sub-Levels (child_a, child_b). Each of the child levels have a trigger volume in them. The Persistent (parent) level then queries both levels via the blueprint interface to see if the Player’s pawn is overlapping with their respective trigger volume.

Here is the Persistent level’s blueprint:

Here is one of the Child level’s implementation of the interface:

Here are the Compiler warnings
(‘ReturnValue’ is already a ‘Level Streaming’, you don’t need…):

The actual blueprint communication works so this isn’t blocking but it’d be great to get rid of these warnings. I’m not sure how else I’d set this up as this is exactly how the example image in the patch notes seen here

I met the same problem…

+1, I met the same problem…

I met the same problem…

Me also… wonder wonder quess.

I met the same problem…
But “Object” Reference to avoid the warning by setting the I was able to .

I really don’t see reason why this message apper, normally this apper when you trying cast object reference to class that it’s already is (for example when you try cast Pawn to Pawn), so cast is pointless and you can call functions on object directly. I will move this question to Bug Raports because it looks like a bug and it should have get more Epic attention (just keep in mind Epic is going back to work in Jan 4). Overall this should not have effect on your game, this warning is just to inform you that this works but it’s pointless, so it’s harmless

Hi Pier Poops,

Can you open your Message Log in editor and tell me the exact warning you are seeing?

Hi Adam,
It shows screen shots of the warning case and not warning case.

What is the class type of the Object Reference variable? Additionally, is that interface located within the streaming level that you are getting a return value off of?

“Object Reference” variable type is “Object”.
It show “Details” to “2.png”.

The reason I ask is because interfaces typically don’t require a reference to the asset that contains the interface, as the way they are designed is a general call that either succeeds or fails if the asset has the interface, instead of being called like a typical function from the asset, which requires a reference to the asset to succeed. As such, it makes sense that the warning appears stating that it is already a reference to type . The object reference is not originally of type so the warning won’t appear.