use* items are applied to ApplicationBuilder in reverse order.

[deapsquatter]

In Application.fs new items are prepended as follows:

config::state.AppConfigs

The AppConfigs list is then copied in the same order to a ResizeArray:

// as we want to add middleware to our pipeline, we can add it here and we'll fold across it in the end
let useParts = ResizeArray<IApplicationBuilder -> IApplicationBuilder>()

// user-provided middleware
state.AppConfigs |> List.iter (useParts.Add)

Finally we fold over the ResizeArray in the same order:

let wbhst =
  wbhst.Configure(fun ab ->
    (ab, useParts)
    ||> Seq.fold (fun ab part -> part ab)
    |> ignore
  )

This breaks middleware that depends on a logical order as added in the application computation expression.

In this example static content does not get redirected to SSL even thought thats what a user would expect:

let app = application {
force_ssl
use_static
}

The use_static has to be before the force_ssl to work correctly because of this bug (not intuitive)