Crash on exit

Flew around world placing objects, banners, skulls and digging down to bedrock and messing around with settings, after session I click save and quit to title and this crash occurred.

Description: Updating screen events

java.lang.ArrayIndexOutOfBoundsException: -1
	at java.util.ArrayList.fastRemove(Unknown Source)
	at java.util.ArrayList.remove(Unknown Source)
	at sd.e(SourceFile:301)
	at cwk.t(SourceFile:305)
	at brk.a(SourceFile:1946)
	at brk.a(SourceFile:1934)
	at bvl.a(SourceFile:46)
	at bvs.a(SourceFile:342)
	at bvs.k(SourceFile:405)
	at bvs.p(SourceFile:382)
	at brk.r(SourceFile:1480)
	at brk.ar(SourceFile:875)
	at brk.a(SourceFile:310)
	at net.minecraft.client.main.Main.main(SourceFile:120)

Description: Exception in server tick loop

java.lang.NegativeArraySizeException
	at java.util.Arrays.copyOf(Unknown Source)
	at java.util.Arrays.copyOf(Unknown Source)
	at java.util.ArrayList.toArray(Unknown Source)
	at java.util.ArrayList.<init>(Unknown Source)
	at com.google.common.collect.Lists.newArrayList(Lists.java:129)
	at cwk.t(SourceFile:303)
	at ra.a(SourceFile:534)
	at qt.c(SourceFile:147)
	at net.minecraft.server.MinecraftServer.y(SourceFile:608)
	at net.minecraft.server.MinecraftServer.x(SourceFile:514)
	at cwk.x(SourceFile:138)
	at net.minecraft.server.MinecraftServer.run(SourceFile:430)
	at java.lang.Thread.run(Unknown Source)