-fdump-ast raises internal error on lex.c

[tj90241]

$ ./8cc -fdump-ast lex.c ((ushort)=>ushort)bswap_16(ushort lv=bsx){(return (conv ((int)=>(ushort) (| (& (conv (>> (conv lv=bsx=>int) 8)=>int) 255) (<< (& (conv lv=bsx=>int) 255) 8)))=>ushort));}((uint)=>uint)bswap_32(uint lv=bsx){(return (conv (| (| (| (>> (& lv=bsx -16777216) 24) (>> (& lv=bsx (conv 16711680=>uint)) 8)) (<< (& lv=bsx (conv 65280=>uint)) 8)) (<< (& lv=bsx (conv 255=>uint)) 24))=>uint));}[ERROR] debug.c:115: lex.c:540:2: internal error

[tj90241]

Fixed in #43