The bug
Biome-specific structures can spawn on other biomes other than their respective biome in superflat worlds.
How to reproduce
Try reproducing by using the "Overworld" superflat preset but before generating, change the biome ID from 1 (Plains) to 40 (The End - Floating Islands).
Preset
minecraft:bedrock,59*minecraft:stone,3*minecraft:dirt,minecraft:grass_block;40;village,biome_1,decoration,stronghold,mineshaft,lake,lava_lake,dungeonLinked issues
is duplicated by 13
MC-125542
Jungle and Desert Temples in superflat can spawn regardless of the biome
Resolved
MC-125593
The biome_1 scructures generates on all biomes
Resolved
MC-125696
Temples appearing in wrong biomes in Superflat worlds
Resolved
MC-126429
all structures spawn ion the plains on a flat world
Resolved
MC-126448
Igloo in "Tunnelers' Dream"
Resolved
Attachments
Comments 13
Can confirm for 18w09a. I have seen igloos, desert temples, villages, zombie villages, jungle temples, witch huts and the new ocean structures in a Superflat world that is entirely Roofed Forest.
Same problem with the Desert Preset. Confirmed in 18w08b and 18w09a. I see igloos, jungle temples, witch huts, and the new ocean ruins structures.
I also see way too many structures, the structure density is extremely high. Also many small lava lakes, they are everywhere.
I also see very large groups of spawned mobs that should not spawn (zombies and skeletons at start of game day), that don't seem to notice the blazing sun until I move near them, at which point they start burning. In case that's related.
I see deep pits full of spiders. Another new feature? Pretty scary! I would not want to fall into one.
Here's my conjecture from my duplicate ticket (MC-126629):
On the structure issue I wonder if the terrain generator realises this is a preset desert, but the structure generator is failing to notice the terrain is desert-only? Is the desert preset applied as a post-generation mask over the 'real' biome type, and the structure generator is accessing the 'real' biome type? I'm just guessing.
Checking the standard Superflat world with no customisation, it has no structures at all apart from Villages. But for some reason it is swarming with slimes in every direction for as far as the eye can see. Slimes and passive mobs. 18w09a.
The Village types are varied even though the terrain is identical (nothing but grass). So possibly the same issue, just less dramatic because the only structures are Villages?
Are you seeing it in that snapshot? Odd since it's been marked resolved for years.
To verify, create a superflat desert and fly around looking for igloos.
It probably has been fixed indeed back then, but resurfaced now.
MC-180603 is describing this bug in the latest versions, you can vote for that report and start watching it.
Have you seen this with biome 40 only or does it affect other biomes as well?Edit: Apparently affects other types as well, I am seeing desert temples with the "Snowy Kingdom" superflat preset