[11:03:32 FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.VerifyError: Bad local variable type
Exception Details:
  Location:
    net/minecraft/server/v1_12_R1/SharedConstants.isAllowedChatCharacter(C)Z @0: aload_0
  Reason:
    Type integer (current frame, locals[0]) is not assignable to reference type
  Current Frame:
    bci: @0
    flags: { }
    locals: { integer }
    stack: { }
  Bytecode:
    0x0000000: 2ab8 0016 ac00 0000 0000 00bf 0000 0000
    0x0000010: 00bf 0000 0000 00bf 0000 00bf bfbf
  Stackmap Table:
    full_frame(@5,{},{Object[#24]})
    same_locals_1_stack_item_frame(@12,Object[#24])
    same_locals_1_stack_item_frame(@18,Object[#24])
    same_locals_1_stack_item_frame(@24,Object[#24])
    same_locals_1_stack_item_frame(@28,Object[#24])
    same_locals_1_stack_item_frame(@29,Object[#24])

        at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_275]
        at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_275]
        at net.minecraft.server.v1_12_R1.SystemUtils.a(SourceFile:47) ~[server.jar:git-Paper-33d42c8e]
        at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:862) ~[server.jar:git-Paper-33d42c8e]
        at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:423) ~[server.jar:git-Paper-33d42c8e]
        at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:786) ~[server.jar:git-Paper-33d42c8e]
        at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:678) ~[server.jar:git-Paper-33d42c8e]
        at java.lang.Thread.run(Thread.java:748) [?:1.8.0_275]