Strange compilation error with duplicate module resolution and running mix test

[wkirschbaum]

Elixir and Erlang/OTP versions

Erlang/OTP 26 [erts-14.1.1] [source] [64-bit] [smp:12:12] [ds:12:12:10] [async-threads:1] [jit:ns]

Elixir 1.15.7 (compiled with Erlang/OTP 26)

Operating system

GNU Linux

Current behavior

With the following steps to reproduce:

$ mix new foo
$ cd foo
$ mix test ( passes )

$ cp lib/foo.ex lib/bar.ex
$ mix test ( passes with warning )

edit lib/bar.ex and change module name from

defmodule Foo do
...

to

defmodule Foo.Bar do
...

$ mix test

Compiling 1 file (.ex)
Generated foo app
error: module Foo is not loaded and could not be found
  test/foo_test.exs:3: FooTest (module)


== Compilation error in file test/foo_test.exs ==
** (CompileError) test/foo_test.exs: cannot compile module FooTest (errors have been logged)
    (ex_unit 1.15.7) expanding macro: ExUnit.DocTest.doctest/1
    test/foo_test.exs:3: FooTest (module)

mix compile --force does not help, it seems like i have to remove the module, compile and then re-add it to fix the error.

Expected behavior

To not have compilation errors when duplicate module duplicates gets resolved.