Route with undefined module/function does not generate warning when compiled

[lkarthee]

Environment

• Elixir version (elixir -v): 1.13
• Phoenix version (mix deps): "~> 1.6.4"
• Operating system: Mac OS 12.0.1

Expected behavior

  scope "/", HelloLiveWeb do
    pipe_through :browser

    get "/", PageController, :index # <-- module and function is defined
    get "/pages/:id", PageController, :undefined_func # <-- function is not defined
    get "/tests/:id", SomeUndefinedController, :id # <-- module is not defined
    live "/demo", Demo # <-- module is defined
    live "/hello_demo", UndefinedDemoLive # <-- module is not defined 
  end

Routes with undefinded module or function should generate warnings - 3 warnings expected when routes are compiled.

• function HelloLiveWeb.PageController. undefined_func/2 is undefined
• module SomeUndefinedController is not available or undefined
• module UndefinedDemoLive is not available or undefined

Actual behavior

Only one warning is generated :

 warning: HelloLiveWeb.SomeUndefinedController/1 is undefined (module HelloLiveWeb.SomeUndefinedController is not available or is yet to be defined)
  lib/hello_live_web/router.ex:22: HelloLiveWeb.Router.__checks__/0

Undefined functions in plain controllers and undefined live controllers don't generate any warnings.