Why are types not allowed to pass through concepts?

[IcedQuinn]

This seems odd given that a concept is able to successfully interrogate a type itself has some properties. But something blocks passing the type itself even after the concept clears it as OK.

local FlompFn = @function(self: pointer, msg: string)
local FlompDg = @record{
  data: pointer,
  func: FlompFn,
}

local some_delegate = #[concept(function(attr)
  if attr.value.is_record and
    attr.value.fields['data'] and
    attr.value.fields['data'].type.is_pointer and
    attr.value.fields['func'] and
    attr.value.fields['func'].type.is_function then
      return true
  end
  return false
end)]#

local some_function = #[concept(function(attr)
  return attr.type.is_function
end)]#

local some_pointer = #[concept(function(attr)
  return attr.type.is_pointer
end)]#

local function wrap(dg: some_delegate, data: some_pointer, fn: some_function): isize
  return 0 --dg{data=data, func=fn}
end

local Object = @record{
  yeet: string
}

function Object:flomp(msg: string)
  print("instance ", self.yeet, " is flomping: ", msg)
end

local o: Object

local k = wrap(FlompDg, &o, Object.flomp)

functors.nelua:70:15: error: in call of function 'wrap' at argument 1: invalid return for concept 'some_delegate': cannot be of the type 'type'
local k = wrap(FlompDg, &o, Object.flomp)