No overload matches with argument NoReturn

[wooster0]

record A, argument : UInt64

variable1 = "hello"

if variable1.is_a?(UInt64)
  variable2 = variable1
end

exit if variable2.nil?

A.new(argument: variable2)

Error in line 11: no overload matches 'A.new', argument: NoReturn
Overloads are:
 - A.new(argument : UInt64)

I don't think variable2's type should be NoReturn here.
But now if I remove argument: from the last line (so A.new(variable2)), no compile-time error happens, but I expect the same to happen since A.new(variable2) and A.new(argument: variable2) should normally do the same thing.