Internal parser panic due to %nonassoc #344
Description
I am trying to write a parser for a simple language that includes operators like == or > that should be nonassociative. The Happy (v 2.1.7) file was generated with BNFC (v 2.9.6.1), originally with ambiguities. At this point, an expression like a == b == c is recognized.
When adding %nonassoc '==' inside the Happy file (in the right position, after the tokens are declared and before the parser rules are defined) I would expect a syntax error (as it happen when I try to validate expressions that are not well formed), however I get this message when trying to parse the expression a == b == c.
TestElang: Internal Happy parser panic. This is not supposed to happen! Please open a bug report at https://github.com/haskell/happy/issues.
CallStack (from HasCallStack):
error, called at ./ParElang.hs:1615:17 in main:ParElang
The line 1615 in question is just the definition of notHappyAtAll. How to solve this?
This is the file that generates the error:
https://github.com/andr3wsm/elang-bug/blob/main/ParElang.y