[Patch] libstdc++/23425

[Paolo Carlini]

Howard Hinnant wrote:

> And of course this all needs to be done without breaking exception 
> safety.  Do we run (and pass) Abrahams exception safety test?  
> Additionally, if we don't already have it, we could use some 
> exception safety tests that stress the corner cases of adding, 
> deleting, transferring nodes both on empty deques and non-empty  deques.

About this, Benjamin filed libstdc++/21772, dunno whether you like the
approach or anyway want to help for it...

Paolo.