anyChar fails on '\uFFFF'

[brianberns]

'\uFFFF' is FParsec's special end-of-stream character (EOS). Unfortunately, there are some files in the wild that actually contain this character, and anyChar will fail when it encounters it:

let str = string EOS
let result = runParserOnString anyChar () "" str
printfn "%A" result

Output:

Failure:
Error in Ln: 1 Col: 2
�
 ^
Note: The error occurred at the end of the input stream.
Expecting: any char