crash log

Exception in thread "LWJGL Application" com.badlogic.gdx.utils.GdxRuntimeException: java.lang.VerifyError: Method expects a return value
Exception Details:
  Location:
    com/megacrit/cardcrawl/cards/red/Havoc.canUse(Lcom/megacrit/cardcrawl/characters/AbstractPlayer;Lcom/megacrit/cardcrawl/monsters/AbstractMonster;)V @8: ireturn
  Reason:
    Type integer (current frame, stack[0]) is not assignable to top (from method signature)
  Current Frame:
    bci: @8
    flags: { }
    locals: { 'com/megacrit/cardcrawl/cards/red/Havoc', 'com/megacrit/cardcrawl/characters/AbstractPlayer', 'com/megacrit/cardcrawl/monsters/AbstractMonster' }
    stack: { integer }
  Bytecode:
    0x0000000: 2ab8 00b2 9900 0504 ac2a 2b2c b800 b899
    0x0000010: 0006 0357 b12a 2b2c b700 bb57 b1
  Stackmap Table:
    same_frame(@9)
    same_frame(@21)

	at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:133)
Caused by: java.lang.VerifyError: Method expects a return value
Exception Details:
  Location:
    com/megacrit/cardcrawl/cards/red/Havoc.canUse(Lcom/megacrit/cardcrawl/characters/AbstractPlayer;Lcom/megacrit/cardcrawl/monsters/AbstractMonster;)V @8: ireturn
  Reason:
    Type integer (current frame, stack[0]) is not assignable to top (from method signature)
  Current Frame:
    bci: @8
    flags: { }
    locals: { 'com/megacrit/cardcrawl/cards/red/Havoc', 'com/megacrit/cardcrawl/characters/AbstractPlayer', 'com/megacrit/cardcrawl/monsters/AbstractMonster' }
    stack: { integer }
  Bytecode:
    0x0000000: 2ab8 00b2 9900 0504 ac2a 2b2c b800 b899
    0x0000010: 0006 0357 b12a 2b2c b700 bb57 b1
  Stackmap Table:
    same_frame(@9)
    same_frame(@21)

	at com.megacrit.cardcrawl.helpers.CardLibrary.addRedCards(CardLibrary.java:500)
	at com.megacrit.cardcrawl.helpers.CardLibrary.initialize(CardLibrary.java:415)
	at com.megacrit.cardcrawl.core.CardCrawlGame.create(CardCrawlGame.java:282)
	at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:149)
	at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:126)