Imported From: https://issues.scala-lang.org/browse/SI-9488?orig=1
Reporter: @retronym
Affected Versions: 2.11.8

@retronym said:
[~viktorklang] WDYT?

Viktor Klang (viktorklang) said:
AFAIK this has already been "fixed" in 2.12.x: https://github.com/scala/scala/blob/2.12.x/src/library/scala/concurrent/impl/Promise.scala#L46

However, I think the solution in 2.12.x is a bit dodgy in the sense that toString now has a temporal aspect to it, but perhaps that is not a problem since the same thing affects virtually every mutable object since the dawn of time.

@SethTisue said:
This was reported against 2.11.8 by @nilskp at https://groups.google.com/d/msg/scala-user/FjhQGH7TII0/DPz8tOVUAgAJ

I suggest we backport the 2.12 fix for 2.11.9.

@SethTisue said:
another possibility would be to restore the 2.11.7 behavior:

scala> concurrent.Promise.apply[String]()
res0: scala.concurrent.Promise[String] = scala.concurrent.impl.Promise$DefaultPromise@71dac704

Viktor Klang (viktorklang) said:
The appropriate fix is to move the toString overrides in 2.12 to 2.11

The old version is problematic, not only does it expose that a Future is also a Promise, but it also involved System.identityHashCode, which is not only problematic from the fact that it needs to be stored in the object header, but also because it conveys 0 meaning. Thoughts?

@lrytz said:
scala/scala#5056