Successfully parse 'a + b /= c' #259
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We attempt to parse '/=' before we parse '/', which parses successfully. But because in this expression we previously encountered a '+', we're at a precedence leve where we are only evaluating operators with a higher precedence than '/='. So we don't check for '/=', and then we see a '/' which commits, and then we get stuck because we don't expect a '='. This fixes the issue by checking, for the '/' operator, that it is not followed by a '='. Ideally we should only do this if the operator precedence is higher than the precendence for '/=', but that data is not available for the parser. Similarly, this fixes the parsing of 'a && b <| c' which has the same problem.
jfmengels
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Superseded by #260. |
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Fixes #258
We usually attempt to parse '/=' before we parse '/', which parses successfully.
But because in this expression we previously encountered a '+', we're at a precedence leve where we are only evaluating operators with a higher precedence than '/='. So we don't check for '/=', and then we see a '/' which commits, and then we get stuck because we don't expect a '='.
This fixes the issue by checking, for the '/' operator, that it is not followed by a '='. Ideally we should only do this if the operator
precedence is higher than the precendence for '/=', but that data is not available for the parser.
Similarly, this fixes the parsing of 'a && b <| c' which has the same problem.
cc @lue-bird, let me know if I missed something or if there is a better or more performant way to do this.
On top of this, I also made a small improvement to the printing of
DeadEnds in the tests.