Nicolas Cellier uploaded a new version of Traits to project The Trunk:
http://source.squeak.org/trunk/Traits-nice.311.mcz

==================== Summary ====================

Name: Traits-nice.311
Author: nice
Time: 10 June 2017, 6:00:07.752334 pm
UUID: cc5f8bd4-1879-4453-87cf-337d4ec0da45
Ancestors: Traits-ul.310

Massively replace ifNotNilDo: by ifNotNil:
We don't need two different selectors to do a single thing.

=============== Diff against Traits-ul.310 ===============

Item was changed:
  ----- Method: Trait>>category (in category 'accessing') -----
  category
  	"Answer the system organization category for the receiver. First check whether the
  	category name stored in the ivar is still correct and only if this fails look it up
  	(latter is much more expensive)"
  
  	| result |
+ 	category ifNotNil: [ :symbol |
- 	category ifNotNilDo: [ :symbol |
  		((SystemOrganization listAtCategoryNamed: symbol) includes: self name)
  			ifTrue: [ ^symbol ] ].
  	category := (result := SystemOrganization categoryOfElement: self name).
  	^result!