What does the symbols in Ambiguous Alternatives Detected error mean?

[durianwaffle]

Hi, I am using Langium which parse document based on Chevrotain.
In my code editor, I saw an error for some documents saying that: Ambiguous Alternatives Detected: <12, 14> in <OR1> inside <Primary​> Rule, <ID, ;, ID> may appears as a prefix path in all these alternatives. See: https://chevrotain.io/docs/guide/resolving_grammar_errors.html#AMBIGUOUS_ALTERNATIVES For Further details. But I don't really understand the numbers 12, 14 nor OR1 mean in my grammar. And this error leads to the failure of ComputedScopes for that document.
Anyone knows what do they mean?

[msujew]

Hey @durianwaffle,

this specific error comes from the chevrotain allstar plugin that enables unlimited lookahead. In particular, this error means that the 12th and 14th of your first alternative within the Primary parser rule are impossible to differentiate from one another. Can you share your grammar? Otherwise it's impossible to help you in any meaningful way.