My guess is this bug was born when multiline parameters were introduced, but regardless to how long its gone unnoticed the following code does not work:

def new Write (stream : NP.Stream, offset : int32,
                           [CCode(array_length_pos=0.9)]
                           buffer :  array of char) : int32

Reports this error:
error: syntax error, expected end of line but got identifier with previous `]'

It appears that EOL's in parameter blocks are being eaten on a higher level, and thus the end of the parse_attributes function in never finds the requisite EOL.

Attached is a git bundle (1 changeset) that fixes this and expands Genie syntax to also allow attribute blocks inline with parameters as well as on separate lines as before.