<<EOF>> is silently accepted but generates a parser with compile errors

[nthykier]

Writing a grammar with the token <<EOF>> (instead of <<eof>>) is accepted without any hints of issues by the parser generator. It results in a grammar file referencing a non-existing method called EOF (instead of eof).

I would recommend that the IDEA editor would highlight this as a "likely mistake" with a suggestion to lowercase it to the expected value. I find this particular relevant as the JFlex lexer expects <<EOF>> in all caps meaning the two related languages disagree on the casing.

In the concrete case, I had:

rule ::= subrule (TOKEN_A* subrule)* TOKEN_A* (TOKEN_B|<<EOF>>)

Which should have been:

rule ::= subrule (TOKEN_A* subrule)* TOKEN_A* (TOKEN_B|<<eof>>)