xxdiff 4.0b1 might solve your issue (your example just works fine for me)
Note, however, than even wirh xdiff 3.2, I have no crash (on mac) but just a bunch of such messages in the console:
xxdiff(23179,0xa0794500) malloc: *** error for object 0x2203f60: pointer being freed was not allocated
*** set a breakpoint in malloc_error_break to debug
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xxdiff 4.0b1 might solve your issue (your example just works fine for me)
Note, however, than even wirh xdiff 3.2, I have no crash (on mac) but just a bunch of such messages in the console:
xxdiff(23179,0xa0794500) malloc: *** error for object 0x2203f60: pointer being freed was not allocated
*** set a breakpoint in malloc_error_break to debug