Macro: fails with a string that ends with a backslash

[maiha]

minimum code

macro foo
  "\\"
end

$ crystal test.cr
In test.cr:1:7

 1 | macro foo
           ^
Error: unterminated macro

It fails in all versions 0.27.2, ... , 0.30.0.

FYI

Since it works with "\\a", it simply looks like a parsing problem.

Best regards,