Bug Assembly reload performance degradation due to boxing in StyleCatalog.SetIndex<T>

Submitting a bug report for this one is a bit hard, so I'm posting it here as a heads up.

UnityEditor.StyleSheets.StyleCatalog.SetIndex<T> cost about 25% of my assembly reload time (total of about 14s while deep profiling).



All this cost is coming from the IndexOf in the generic list.
That is about 3.4s (of which 2.2 are just due to garbage collection due to the default equality comparer being used in value types). It also costs 75MB of allocations (from a total of about 190MB) due to this heavy boxing.

It would probably help to have non-generic overloads (or force T to have IEquatable<> implemented).
Since this is called many times, the times are adding up fast.

This is a low hanging fruit with quite impressive gains if optimized.

 

Thank you for spotting it!
The fix which implements IEquatable<> for StyleCatalog structs is on the way to 2019.3

 

Incredible!
I was baffled to see such a delicious fruit hanging, but I guess I was too late to notice and it had already been picked (and eaten).

Thanks for keeping us posted!