`can't find type required by parameter` error when referencing Scala 3 code

[jadenPete]

Reproduction steps

Scala 2 version: 2.13.18
Scala 3 version: 3.7.4

1. Clone this minimum reproducibility case:
   https://github.com/jadenPete/scala-cant-find-type-bug-reproduction

2. Run sbt compile

3. Observe the following compilation error:

[error] <REDACTED>/scala2/Main.scala:2:45: can't find type required by parameter inner in class Child.Middle: Child.this.Inner; perhaps it is missing from the classpath.
[error]   def useMiddle(child: Child)(middle: child.Middle): Unit = ???
[error]                                             ^
[error] one error found

Problem

I'd expect this to compile.