duplicate properties within same declaration ignored

[Entoarox]

This is a rather unique issue that I only ran into because I was trying to do some stuff using the new flexbox functionality.

The issue happens if the same property is declared twice in the same selector block

#sample selector
{
display:block;
display:box;
}

This causes phpsass to only output the second declaration, while the preview on sass-lang displays the expected behaviour of outputting both. The issue doesnt come up often (as the need to declare a property twice in the same block is rare), but as the 'box' property for display isnt supported universally without vendor prefixes yet, this does cause a rather hard to detect bug (as your input css is completely correct, and the output css is the actual issue.)