Case confusion in module name

[mtzguido]

XX.fsti:

module XX

let x : int = 1

val y : int

XX.fst, note the change in case:

module Xx

let y = x

In the IDE, it starts but we get identifier not found for x:

In the CLI, a bad error:

$ ./bin/fstar.exe XX.fst
* Error 161:
  - mismatch between pre-module and module

1 error was reported (see above)