So, I was mining on my local host when I used torches to break gravel, by having a falling sand entity fall onto a torch and break. This caused the localhost to crash,  and upon repeating this I got the same crash. This applies for 18w30b too.

---- Minecraft Crash Report -------- Minecraft Crash Report ----// Oops.
Time: 7/26/18 7:38 AMDescription: Exception ticking world entities
java.lang.ArrayIndexOutOfBoundsException: -1 at it.unimi.dsi.fastutil.objects.ObjectLinkedOpenHashSet.fixPointers(ObjectLinkedOpenHashSet.java:851) at it.unimi.dsi.fastutil.objects.ObjectLinkedOpenHashSet$SetIterator.remove(ObjectLinkedOpenHashSet.java:1057) at axu.l(SourceFile:1118) at tc.l(SourceFile:493) at net.minecraft.server.MinecraftServer.b(SourceFile:736) at sn.b(SourceFile:358) at net.minecraft.server.MinecraftServer.a(SourceFile:661) at net.minecraft.server.MinecraftServer.run(SourceFile:564) at java.lang.Thread.run(Unknown Source)

A detailed walkthrough of the error, its code path and all known details is as follows:---------------------------------------------------------------------------------------
– Head --Thread: Server threadStacktrace: at it.unimi.dsi.fastutil.objects.ObjectLinkedOpenHashSet.fixPointers(ObjectLinkedOpenHashSet.java:851) at it.unimi.dsi.fastutil.objects.ObjectLinkedOpenHashSet$SetIterator.remove(ObjectLinkedOpenHashSet.java:1057) at axu.l(SourceFile:1118) at tc.l(SourceFile:493)
– Affected level --Details: Level name: world All players: 1 total; [te['Speak2Erase'/128618, l='world', x=197.20, y=46.00, z=318.54]] Chunk stats: ServerChunkCache: 661 Drop: 0 Level seed: -6626156711704036638 Level generator: ID 00 - default, ver 1. Features enabled: true Level generator options: {} Level spawn location: World: (-48,64,225), Chunk: (at 0,4,1 in -3,14; contains blocks -48,0,224 to -33,255,239), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511) Level time: 1363478 game time, 1424967 day time Level dimension: 0 Level storage version: 0x04ABD - Anvil Level weather: Rain time: 113195 (now: false), thunder time: 105704 (now: false) Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: falseStacktrace: at net.minecraft.server.MinecraftServer.b(SourceFile:736) at sn.b(SourceFile:358) at net.minecraft.server.MinecraftServer.a(SourceFile:661) at net.minecraft.server.MinecraftServer.run(SourceFile:564) at java.lang.Thread.run(Unknown Source)
– System Details --Details: Minecraft Version: 18w30a Operating System: Windows 10 (amd64) version 10.0 Java Version: 1.8.0_101, Oracle Corporation Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation Memory: 171851376 bytes (163 MB) / 1155006464 bytes (1101 MB) up to 3569876992 bytes (3404 MB) JVM Flags: 0 total;  Profiler Position: N/A (disabled) Player Count: 1 / 20; [te['Speak2Erase'/128618, l='world', x=197.20, y=46.00, z=318.54]] Data Packs: vanilla Is Modded: Unknown (can't tell) Type: Dedicated Server (map_server.txt)