Can't mark whitespaces as necessary

[ElBe-Plaq]

When trying to mark a whitespace as necessary, parsing will fail at Pos(0, 0).

Example grammar:

file = _{ SOI ~ ((import) ~ ((";" ~ NEWLINE?) | (";"? ~ NEWLINE))?)* ~ EOI }

import = { "import" ~ WHITESPACE+ ~ identifier }

identifier = { ASCII_ALPHA ~ (ASCII_ALPHA | "_")* | ("_")* ~ ASCII_ALPHA ~ (ASCII_ALPHA | "_")* }

WHITESPACE = _{ " " | "\t" }

Input: import xy

Error:

 --> 1:1
  |
1 | import xy
  | ^---
  |
  = expected EOI or import

I tested it on my machine and the online playground.

I have not opened an issue yet, because I don't know if this is intentional.

My repository: https://github.com/I-Language-Development/I-language-rust/tree/issue-43

[ElBe-Plaq]

Found answer in #628.