Killing guardian with lava does not give cooked fish

The bug

You get raw fish from roasting a guardian with lava or fire instead of the expected cooked fish. Also flame or fire aspect give raw fish.

Code analysis / fix

Fix by Marcono1234 can be found in this comment.

Note

Not completely fixed in snapshot 16w38a; fish dropped by minecraft:gameplay/fishing/fish is still uncooked (used by guardians as player kill loot).