Mob 0.7.12 has been released.

Fixed

• ~MOB now raises a clear error when @foo is used without assigns in
  scope. The @foo → assigns.foo shorthand (0.7.11) only works inside a
  render(assigns); used in an ordinary helper function (positional args — the
  idiomatic composite pattern) it compiled to a cryptic “undefined variable
  assigns”. The sigil now guards with Macro.Env.has_var?(caller, {:assigns, nil}) (the same check Phoenix’s ~H uses) and raises a CompileError naming
  the fix ({title} instead of @title). Only @-using templates trigger it —
  a static ~MOB(<Text text="hi"/>) in a positional-arg helper still compiles.
  (MOB-5, #56)

Documentation

• Worked component-authoring examples in the Components guide. The
  “Defining your own components” section now carries two complete, runnable
  screens — a function composite and a tag composite — spelling out the
  tag→atom rule and where on_* event-target auto-injection applies (a
  composite tag’s own props vs a plain widget in its children). The @assigns
  section documents that @foo only works where assigns is in scope and
  steers helpers to positional {var}. (#56, #57)