Cryptic "undefined function arg0/0" error message in EEx templates

I’ve tested with more versions and it still doesn’t compile…

  • 1.10.04-otp-22
  • 1.10.04-otp-23
  • 1.11.03-otp-22
  • 1.11.03-otp-23

I have no clue what this could be… Do you have any other suggestions?