If you swim in the water and open the inventory the game crashes (in creative mode tested)

Unreported exception thrown!
java.lang.ClassCastException: cby$b cannot be cast to amn
at cda.a(SourceFile:39)
at ccy.f(SourceFile:84)
at ccy.a(SourceFile:73)
at ccx.c(SourceFile:186)
at ccx.a(SourceFile:114)
at ccx.a(SourceFile:78)
at ccg.c(SourceFile:56)
at cau.a(SourceFile:310)
at bxe.a(SourceFile:728)
at bxe.av(SourceFile:1335)
at bxe.m(SourceFile:1220)
at bxe.b(SourceFile:791)
at bxe.a(SourceFile:381)
at net.minecraft.client.main.Main.main(SourceFile:141)