Parsec returns additional, spurious error messages on parserFail

[ksvanhorn]

Consider the following code entered in ghci:

Parsec.parse (Parsec.many1 Parsec.digit <* Parsec.parserFail "foo") "" "123"

Here is the result:

Left (line 1, column 4):
unexpected end of input
expecting digit
foo

The error messages "unexpected end of input" and "expecting digit" should not be there.

This is simplified from a more involved example in which the result of parsing a number is checked, and parserFail is called if the number is out of bounds.

[buggymcbugfix]

I'm running into the same issue :(

[nomeata]

Yes, also curious for a good idiom about reporting such error messages, e.g. for

  do n <- many1 digit
       when (n < 0) fail "must not be empty"
       return n

where I’d somehow like to attache the error to the span parsed by many1 digit.