Scala annotation yields warning about "no valid targets"

[scabug]

This seems to work in Scala 2.10.4 but no more in Scala 2.11.x.

Welcome to Scala version 2.10.4 (Java HotSpot(TM) 64-Bit Server VM, Java 1.7.0_51).
Type in expressions to have them evaluated.
Type :help for more information.

scala> class annot extends scala.annotation.StaticAnnotation
defined class annot

scala> trait A { @annot val x: Int }
defined trait A

scala> :q

[success] Total time: 62 s, completed Aug 23, 2014 9:13:32 PM
> ++ 2.11.2
[info] Setting version to 2.11.2
[info] Set current project to REPL (in build file:/Users/leo/REPL/)
> console
Welcome to Scala version 2.11.2 (Java HotSpot(TM) 64-Bit Server VM, Java 1.7.0_51).
Type in expressions to have them evaluated.
Type :help for more information.

scala> class annot extends scala.annotation.StaticAnnotation
defined class annot

scala> trait A { @annot val x: Int }
<console>:8: warning: no valid targets for annotation on value x - it is discarded unused. You may specify targets with meta-annotations, e.g. @(annot @getter)
       trait A { @annot val x: Int }
                  ^
defined trait A

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-8813?orig=1
Reporter: Leonard Schneider (leonard.schneider)
Affected Versions: 2.11.1, 2.11.2, 2.11.5, 2.11.8

[scabug]

Leonard Schneider (leonard.schneider) said:
I've just realized this warning was intended for reflection about annotation, which is precisely what I wanted to do. See #6325.

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Tim Feuerbach (tfeuerbach) said:
The warning should not be issued for annotations that are elided by the compiler anyway, e.g. @BeanProperty:

scala> trait A {@BeanProperty var x: Int }
<console>:8: warning: no valid targets for annotation on method x - it is discarded unused. You may specify targets with meta-annotations, e.g. @(scala.beans.BeanProperty @getter)
       trait A {@BeanProperty var x: Int }

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Andrei Pozolotin (andrei.pozolotin) said:
still affects 2.11.5 both java and scala annotations

[scabug]

Helena Edelson (helena) said (edited on Feb 13, 2015 3:45:39 PM UTC):
I am trying to upgrade our project to scala 2.11 and add a cross build and see this same compiler error with Scala 2.11.0 through 5 with: (for sc and rtf @transient)

{code}
class CassandraRDD[R] private[connector] (
@transient sc: SparkContext,
val connector: CassandraConnector,
val keyspaceName: String,
val tableName: String,
val columnNames: ColumnSelector = AllColumns,
val where: CqlWhereClause = CqlWhereClause.empty,
val readConf: ReadConf = ReadConf())(
implicit
ct : ClassTag[R], @transient rtf: RowReaderFactory[R])
extends RDD[R](sc, Seq.empty) with Logging{code}

Same compiler error if I use these against 2.11.0 - 5:
@(transient @scala.annotation.meta.field)
@(transient @scala.annotation.meta.getter)

[scabug]

Helena Edelson (helena) said (edited on Feb 13, 2015 4:04:31 PM UTC):
This compiles by 'var' or 'val'-ing the @transient

{code}class CassandraRDD[R] private[connector] (@transient var sc: SparkContext ...){code}

[som-snytt]

Currently relevant ticket is: #6375 as to whether to bring back the warning vilified here.