Build warning on mik_parser.mly

[vog]

I see the following warnings in the build log:

File "lib/mik_parser.mly", line 79, characters 0-6:
Warning: the precedence level assigned to AS is never useful.
File "lib/mik_parser.mly", line 82, characters 0-9:
Warning: the precedence level assigned to LBRACE is never useful.
File "lib/mik_parser.mly", line 81, characters 0-5:
Warning: the precedence level assigned to seq is never useful.
File "lib/mik_parser.mly", line 126, characters 29-32:
Warning: this %prec declaration is never useful.
Warning: 23 states have shift/reduce conflicts.
Warning: 79 shift/reduce conflicts were arbitrarily resolved.
Warning: 124 end-of-stream conflicts were arbitrarily resolved.

Are those warnings justified? Is it easy (and worth it) to fix them?

[zazedd]

Two types of warning from Menhir here

Warnings about precedence:

File "lib/mik_parser.mly", line 79, characters 0-6:
Warning: the precedence level assigned to AS is never useful.
...
Warning: this %prec declaration is never useful.

These are easy enough, can remove the precedence since it is unused, but won't matter much other than showing up as a warning. I only added them to help a human reader

Warnings about shift/reduce and EOS conflicts:

Warning: 23 states have shift/reduce conflicts.
Warning: 79 shift/reduce conflicts were arbitrarily resolved.
Warning: 124 end-of-stream conflicts were arbitrarily resolved.

This is Menhir asking for clarification about the language's design. In particular the conflicts here come from ambiguity in the mikmatch syntax (e.g. postfix operators like *, +, ? interacting with sequences and alternations), which require more than 1 token of lookahead to resolve cleanly, the grammar is not LR(1) in the strict sense (in retrospect I guess I could've %inlined some of them them)

The default shift-reduce conflict solver gives us the default left-to-right greedy semantics that we expect in this case, so the semantics are correct, it just warns us that it had to resolve them.

I'll leave this open as a tracking issue in case someone wants to take a crack at it, but I wouldn't consider it a bug.