One problem related to car stall has been reported for the 2015 Subaru Impreza Wrx. The most recently reported issues are listed below.
Driving on the highway at ~70 mph and suddenly lost all throttle response, the car would not accelerate only loose speed. Engine started to shutter to low rpms, and because of this drastically lost speed and nearly got into an accident with oncoming traffic while moving to the side of the highway to pull over. After eventually pulling over, engine continued to shutter to low rpms and could not hold an idle - would just stall after repeated attempts to start it up. Car was towed to closest dealership and after waiting 4 days finally heard it was the engine wire harness that needed to be replaced. Researching the issue I found that Subaru made a design change for the wire harness to prevent water/moisture failure which is most like what happened to my vehicle. Stuck with a $1400 bill due to a design flaw, I decided to purchase a 2020 model which hopefully doesn't have the same issue. After calling Subaru of north America and explaining the situation, they offered me $1000 towards the new purchase. It was a kind gesture however I question if it is somewhat admission of guilt for the design flaw. 2015 wrx 138k miles was meticulously maintained with all necessary maintenance completed at proper intervals and oil changes every 3-4k miles.