Ensure that cleanup after desugaring is only called once.
Ensure that cleanup after desugaring is only called once.

brownplt/LambdaS5,logchi/LambdaS5,logchi/LambdaS5,brownplt/LambdaS5,logchi/LambdaS5,brownplt/LambdaS5,lijunsong/LambdaS5,lijunsong/LambdaS5,lijunsong/LambdaS5