property functions

[Nick via Digitalmars-d-learn]

The [Property 
Functions](https://dlang.org/spec/function.html#property-functions) documentation reads:

WARNING: The definition and usefulness of property functions is 
being reviewed, and the implementation is currently incomplete. 
Using property functions is not recommended until the 
definition is more certain and implementation more mature.

Is this warning still valid? The standard library appears to 
extensively use property functions.