The U.S.-led coalition headquarters in Iraq said in a written statement that a U.S. F-18 Super Hornet shot down a Syrian government SU-22 after it dropped bombs near the U.S. partner forces, known as the Syrian Democratic Forces. The shootdown was near the Syrian town of Tabqa.
The U.S. military statement said it acted in "collective self defense" of its partner forces and that the U.S. did not seek a fight with the Syrian government or its Russian supporters.
I did say that determining who takes over in eastern Syria when ISIL is defeated would be the interesting part.
UPDATE: In related interesting news, the Iranians fired "several" ballistic missile into Syria from Iran in retaliation for the June 7th ISIL bombings in Iran.
I'm guessing Iran considers their strikes on target if the missiles landed in Syria.
It will really get interesting if Iran fires missiles at US or allied forces in Syria.