Regression in -Wunused in 3.3.7

[mpilquist]

Compiler version

3.3.7

Minimized code

//> using scala 3.3.7
//> using options -Wunused:all

trait Codec[A]
class DiscrimatorCodec[A](val framing: [x] => Codec[x] => Codec[x])

def foo[A] =
  new DiscrimatorCodec[A]([x] => (cx: Codec[x]) => cx)

Output

❯ scala-cli compile u.scala
Compiling project (Scala 3.3.7, JVM (17))
[warn] ./u.scala:8:28
[warn] unused private member
[warn]   new DiscrimatorCodec[A]([x] => (cx: Codec[x]) => cx)
[warn]                            ^
Compiled project (Scala 3.3.7, JVM (17))

Expectation

There should not be an "unused private member" warning on the final line of this source file.

[Gedochao]

Doesn't seem to happen in any stable version of Next.
Last good version: 3.3.6
First bad version: 3.3.7
Only 3.3 LTS affected, hard to bisect given that 3.3 nightlies are currently borked...
@tgodzik @som-snytt I once again ask for your help, any clue? 😅 We likely didn't back port the fix somewhere...

[som-snytt]

This looks like the same as the other one, which I will second-look.