`scaladoc` issues "Flag -classpath set repeatedly" warning, when classpath is set only once

[arixmkii]

Compiler version

3.6.4

Minimized code

A.scala

class A

B.scala

class B extends A

Project setup:

tree
.
├── a
│   └── A.scala
├── b
│   └── B.scala
└── o

4 directories, 2 files

Output

pushd a ; scalac A.scala ; popd

pushd b ; scalac -classpath ../a B.scala ; popd

scaladoc -d o -project b -classpath a b/B.tasty
Flag -classpath set repeatedly
1 warning found

Expectation

No warning issued by scaladoc as classpath is only set once in the command line

[arixmkii]

It actually could be minimized into

A.scala

class A

and then

scalac A.scala

mkdir -p o

scaladoc -d o -classpath /dev/null A.tasty
Flag -classpath set repeatedly
1 warning found

[arixmkii]

Reproduced with 3.7.0-rc1

~/Downloads/scala3-3.7.0-RC1-aarch64-apple-darwin/bin/scaladoc -d o -classpath /dev/null A.tasty
Flag -classpath set repeatedly
1 warning found