(stack trace truncated; use '--show-trace' to show the full, detailed trace)

error: Refusing to evaluate package 'a-0' in /nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-default.nix:19 because it has an invalid meta attrset:
  - a.meta.problems.florp: Invalid value; expected attrs, got
    true
