bazel rules_bison is pretty old

[dabrahams]

Note: this is not really a problem. If you have the time to explain why my attempt to point at bison-3.7.5 didn't work, that would be great. Otherwise feel free to close.

The executable semantics code is full of pointers and low-level haxx in part because nobody knew about https://www.gnu.org/software/bison/manual/html_node/C_002b_002b-Bison-Interface.html or https://www.gnu.org/software/bison/manual/html_node/C_002b_002b-Variants.html

~But using those requires a much newer version of Bison than v3.3.x that is supported by the existing rules_bison~Actually v3.3.2 has the necessary features. I was seeing errors for other reasons I attempted to make my own update that included the new version but bazel merrily kept using the earlier version.

See https://github.com/chandlerc/rules_bison/compare/master...dabrahams:bison-3.7.5 and https://github.com/dabrahams/carbon-lang/compare/existential-handroll...dabrahams:modern-bison?expand=1

Perhaps @chandlerc can help /cc @jsiek

[geoffromer]

Switching to at least Bison 3.7 would enable us to use -Wcounterexamples, which could be pretty handy.

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[jonmeow]

We're not making substantial explorer changes anymore, so the version of bison doesn't affect as much. The long-term plan is to eliminate explorer code in favor of just having the toolchain with similar support, so I'm closing this.

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This issue is labeled inactive because the last activity was over 90 days ago.