grammar org.xtext.example.mydsl.MyDsl with org.eclipse.xtext.common.Terminals

generate myDsl "http://www.eclipse.org/example/mydsl/MyDsl"

Model:
	((things+=Thing) | (refs+=Reference))*
;
	
Thing:
	'thing' name=ID '{'
		stuff += Stuff* 
	'}'
;

Stuff:
	'stuff' name=ID
;

Reference:
	'reference' thing=[Thing] stuff=[Stuff] 
;

class MyDslScopeProvider extends AbstractMyDslScopeProvider {
}

class MyDslScopeProvider extends AbstractDeclarativeScopeProvider {
    def IScope scope_Reference_stuff(Reference reference, EReference ref) {
        scopeFor(reference.thing.stuff)
    }
}

import static org.xtext.example.mydsl.myDsl.MyDslPackage.Literals.*

class MyDslScopeProvider extends AbstractMyDslScopeProvider {

	override getScope(EObject context, EReference reference) {
		switch reference {
			case MY_CLASS__MY_REF:
				return // create the scope as you did with the old API and return  
			case MY_CLASS2__MY_REF2:
				return // create the scope as you did with the old API and return  
			...
		}
		super.getScope(context, reference)
	}
}