Merge pull request #3736 from tesonep/backporting-fix-for-diamond-pro…

…blem-in-stateful-traits

Backport of fix for diamond problem in traits with slots.

src/TraitsV2/TaSequence.class.st

@@ -315,7 +315,7 @@ TaSequence >> validateMethods: aTrait [
 { #category : #validations }
 TaSequence >> validateSlots: anElement [
 	self slots do: [ :e | anElement slots do: [ :other | 
-					(e name = other name and: [ e ~= other ])
+					(e name = other name and: [ e definingClass ~= other definingClass ])
 						ifTrue: [ self error: 'The added trait duplicates an existing slot ' , e name printString ] ] ]
 ]