Program: 61574
Project: 61574
Buggy source:
@Override public List<GraphSourceItem> toSource(SourceGeneratorLocalData localData,SourceGenerator generator) throws CompilationException {
  List<GraphSourceItem> ret=new ArrayList<>();
  ActionSourceGenerator asGenerator=(ActionSourceGenerator)generator;
  HashMap<String,Integer> registerVars=asGenerator.getRegisterVars(localData);
  ret.addAll(enumVariable.toSource(localData,generator));
  ret.add(new ActionEnumerate2());
  List<Action> loopExpr=new ArrayList<>();
  int exprReg=0;
  for (int i=0; i < 256; i++) {
    if (!registerVars.containsValue(i)) {
      registerVars.put("String_Node_Str" + asGenerator.uniqId(),i);
      exprReg=i;
      break;
    }
  }
  int innerExprReg=asGenerator.getTempRegister(localData);
  loopExpr.add(new ActionStoreRegister(exprReg));
  loopExpr.add(new ActionPush(new Null()));
  loopExpr.add(new ActionEquals2());
  ActionIf forInEndIf=new ActionIf(0);
  loopExpr.add(forInEndIf);
  List<Action> loopBody=new ArrayList<>();
  loopBody.add(new ActionPush(new RegisterNumber(exprReg)));
  if (asGenerator.isInFunction(localData) == 2) {
    loopBody.add(new ActionStoreRegister(innerExprReg));
    loopBody.add(new ActionPop());
  }
 else {
    loopBody.addAll(0,asGenerator.toActionList(variableName.toSource(localData,generator)));
    loopBody.add(new ActionSetVariable());
  }
  int oldForIn=asGenerator.getForInLevel(localData);
  asGenerator.setForInLevel(localData,oldForIn + 1);
  loopBody.addAll(asGenerator.toActionList(asGenerator.generate(localData,commands)));
  asGenerator.setForInLevel(localData,oldForIn);
  ActionJump forinJmpBack=new ActionJump(0);
  loopBody.add(forinJmpBack);
  int bodyLen=Action.actionsToBytes(loopBody,false,SWF.DEFAULT_VERSION).length;
  int exprLen=Action.actionsToBytes(loopExpr,false,SWF.DEFAULT_VERSION).length;
  forinJmpBack.setJumpOffset(-bodyLen - exprLen);
  forInEndIf.setJumpOffset(bodyLen);
  ret.addAll(loopExpr);
  ret.addAll(loopBody);
  return ret;
}

Fixed version (ground truth):
@Override public List<GraphSourceItem> toSource(SourceGeneratorLocalData localData,SourceGenerator generator) throws CompilationException {
  List<GraphSourceItem> ret=new ArrayList<>();
  ActionSourceGenerator asGenerator=(ActionSourceGenerator)generator;
  HashMap<String,Integer> registerVars=asGenerator.getRegisterVars(localData);
  ret.addAll(enumVariable.toSource(localData,generator));
  ret.add(new ActionEnumerate2());
  List<Action> loopExpr=new ArrayList<>();
  int exprReg=asGenerator.getTempRegister(localData);
  loopExpr.add(new ActionStoreRegister(exprReg));
  loopExpr.add(new ActionPush(new Null()));
  loopExpr.add(new ActionEquals2());
  ActionIf forInEndIf=new ActionIf(0);
  loopExpr.add(forInEndIf);
  List<Action> loopBody=new ArrayList<>();
  loopBody.add(new ActionPush(new RegisterNumber(exprReg)));
  loopBody.addAll(asGenerator.toActionList(variableName.toSourceIgnoreReturnValue(localData,generator)));
  int oldForIn=asGenerator.getForInLevel(localData);
  asGenerator.setForInLevel(localData,oldForIn + 1);
  loopBody.addAll(asGenerator.toActionList(asGenerator.generate(localData,commands)));
  asGenerator.setForInLevel(localData,oldForIn);
  ActionJump forinJmpBack=new ActionJump(0);
  loopBody.add(forinJmpBack);
  int bodyLen=Action.actionsToBytes(loopBody,false,SWF.DEFAULT_VERSION).length;
  int exprLen=Action.actionsToBytes(loopExpr,false,SWF.DEFAULT_VERSION).length;
  forinJmpBack.setJumpOffset(-bodyLen - exprLen);
  forInEndIf.setJumpOffset(bodyLen);
  ret.addAll(loopExpr);
  ret.addAll(loopBody);
  asGenerator.releaseTempRegister(localData,exprReg);
  return ret;
}