False positive in for comprehension

[fmeriaux]

Hello, in 2.12.7, this warning appear:

[warn] /Users/(..)/Constraint.scala:189:9: parameter value endDate in value $anonfun is never used
[warn]         endDate ← Checks.getDateTime(data, end, endFormat)
[warn]         ^
[warn] one warning found

code:

 def check(data: JsObject)(implicit failures: FailureBuffer): Unit = {
      for {
        beginDate ← Checks.getDateTime(data, start, startFormat)
        endDate ← Checks.getDateTime(data, end, endFormat)
        if beginDate.isAfter(endDate)
      } yield Checks.failWith(failure)
    }

PS: Checks.getDateTime returns Option[DateTime]

scalac option -Ywarn-unused:params.

[hrhino]

looks like a duplicate of #11175