false not used

[shestero]

Reproduction steps

Scala version: 2.13.10 (also checked 2.13.8)

    def pairOriginTarget[T](f: String => Future[T]): Future[List[T]] = Future.sequence(List(req.srcCaseId, req.targetCaseId).map(f))
    for {
      cases @ List(_, target)                    <- pairOriginTarget(gettingCase)
      List(originInstance, targetInstance)       = cases.map(_.caseInstance)
      List(originParts, targetParts)             <- pairOriginTarget(gettingParts)
      ...

    def pairOriginTarget[T](f: String => Future[T]): Future[List[T]] = Future.sequence(List(req.srcCaseId, req.targetCaseId).map(f))
    for {
      cases @ List(_, target)                    <- pairOriginTarget(gettingCase)
      List(originParts, targetParts)             <- pairOriginTarget(gettingParts)
      List(originInstance, targetInstance)       = cases.map(_.caseInstance)
      ...

Problem

The first peace of code produce false compiler message:
pattern var cases in value $anonfun is never used: use a wildcard _ or suppress this warning with cases@_
cases @ List(_, target) <- pairOriginTarget(caseStaticService.getCaseWithPrinting)
The second compiles ok.
I suggest some optimization is to blame.

[som-snytt]

Just the desugaring of for is too complex for the linter. There is an existing ticket.

[SethTisue]

is it #10287 or is that distinct? (local val vs pattern var)

[som-snytt]

That is the duplicatee.