Repro steps from a blank project:
- create a blueprint interface
BPI_Interface
- create a blueprint class
BP_InterfaceImplementation
, child ofActor
, implementsBPI_Interface
- create a blueprint class
BP_InterfaceUser
, child ofActor
- add a variable of the type “array of
BPI_Interface
” toBP_InterfaceUser
, mark it asInstance Editable
- create an empty level and place
BP_InterfaceUser
andBP_InterfaceImplementation
there - select
BP_InterfaceUser
, click “lock” on the details panel, click “+” to add a new item to the array, then drag and drop theBP_InterfaceImplementation
from theWorld Outliner
to the slot, and you get a crash
If you change BP_InterfaceUser
’s variable type to be a single item of BPI_Interface
, then the same actions will not crash the editor, but will fail to make the assignment.
This seems to be reproducable every time. I use UE 4.18, OS is Windows 7.
I attach a barebones project ready for the repro. Instead of BP_InterfaceUser
there are BP_ArrayInterfaceUser
with an array variable that can be used to get the crash, and BP_SingleInterfaceUser
with a single item variable.