I think I found the problem @josevalim. Either my editor or the context generator or my cat added alias HelloWeb.ProductController to the top of router.ex. When I comment that line out I no longer have the problem.

defmodule HelloWeb.Router do
  alias HelloWeb.ProductController
  use HelloWeb, :router

  pipeline :browser do
    plug :accepts, ["html"]
    plug :fetch_session
    plug :fetch_live_flash
    plug :put_root_layout, html: {HelloWeb.Layouts, :root}
    plug :protect_from_forgery
    plug :put_secure_browser_headers
  end

  pipeline :api do
    plug :accepts, ["json"]
  end

  scope "/", HelloWeb do
    pipe_through :browser

    get "/", PageController, :home
    get "/hello", HelloController, :index
    get "/hello/:messenger", HelloController, :show
    resources "/products", ProductController
  end

  # Other scopes may use custom stacks.
  # scope "/api", HelloWeb do
  #   pipe_through :api
  # end

  # Enable LiveDashboard and Swoosh mailbox preview in development
  if Application.compile_env(:hello, :dev_routes) do
    # If you want to use the LiveDashboard in production, you should put
    # it behind authentication and allow only admins to access it.
    # If your application does not have an admins-only section yet,
    # you can use Plug.BasicAuth to set up some basic authentication
    # as long as you are also using SSL (which you should anyway).
    import Phoenix.LiveDashboard.Router

    scope "/dev" do
      pipe_through :browser

      live_dashboard "/dashboard", metrics: HelloWeb.Telemetry
      forward "/mailbox", Plug.Swoosh.MailboxPreview
    end
  end
end

That wont cause any future problems for me if I comment out that second line, will it?

I hate that feature so much, those auto-added aliases has tripped me up a few times as well. If you don’t see it happen you will start to get errors that doesn’t seem to make any sense at all.