Fix #1684 - Correct regression in refactoring extend.
Fix #1684 - Correct regression in refactoring extend.

rashmisajjan/backbone,chyeh727/backbone,yuhualingfeng/backbone,elma-cao/backbone,zhoufan879/backbone,premkumargithub/backbone,Khan/backbone,akre54/backbone,sunday-star/backbone,lastjune/backbone,zhangwei001/backbone,huanglp47/backbone,7213/backbone,gitterHQ/backbone,webapp/library,getshuvo/backbone,dillonforrest/backbone-df,heroazure/backbone,jashkenas/backbone,ridixcr/backbone,udhayam/backbone,alekskorolev/lightbones,streamablevideo/backbone,gmaclennan/backbone,luffy94608/backbone,chyeh727/backbone,wakanpaladin/mybackbone,ppker/backbone,amitpatange88/backbonejs,kuychaco/backbone,timebackzhou/backbone,udhayam/backbone,zgl2007dj/backbone,LovelyL25/backbone.js,ebsco/backbone,gmaclennan/backbone,jridgewell/backbone,moimikey/backbone,aihua/backbone,Connectlegendary/backbone,wangdahoo/backbone,cailong1028/backbone,webapp/library,ridixcr/backbone,wangdahoo/backbone,pandoraui/backbone,howtolearntocode/backbone,yuhualingfeng/backbone,elma-cao/backbone,moccen/backbone,elancom/backbone,liudianpeng/backbone,braddunbar/backbone,npmcomponent/jashkenas-backbone,zdespolit/backbone,paulfalgout/backbone,JesseQin/backbone,nvoron23/backbone,jmeas/backbone,amitpatange88/backbonejs,mrblueblue/backbone,streamablevideo/backbone,braddunbar/backbone,Aplopio/backbone,anhtholee/backbone,sueyeh/backbone,au-phiware/backbone,Niades/backbone,getshuvo/backbone,anhtholee/backbone,sitexa/backbone,trizko/backbone,tibic/backbone,vin100bk/backbone,megawac/backbone,FishbaitHarry/backbone,ThiagoGarciaAlves/backbone,jstrimpel/backbone,moccen/backbone,IsoldaJS/isolda-models,timebackzhou/backbone,dcheepurupalli/backbone,Niades/backbone,DannyDelott/backbone,zhoufan879/backbone,wangcan2014/backbone,jungjung917/backbone,leimd/backbone,Akkuma/backbone,wushuyi/backbone,ThisIsManta/Backbone,FishbaitHarry/backbone,Diwahars/backbone,wxmfront/backbone,linalu1/backbone,ywenjinlin/backbone,yawenl/backbone,componentizr/backbone,mrblueblue/backbone,maryrosecook/backbone-df,wangcan2014/backbone,DannyDelott/backbone,wushuyi/backbone,zhangwei001/backbone,trizko/backbone,feychenie/backbone,maryrosecook/backbone-df,moimikey/backbone,cgvarela/backbone,darrrk/backbone,IsoldaJS/isolda-pubsub,ebsco/backbone,mpapp/backbone,linalu1/backbone,Aplopio/backbone,sumyfly/backbone,guigrpa/backbone,liudianpeng/backbone,vincent1988/backbone,zgl2007dj/backbone,wjb12/backbone,feychenie/backbone,fanhc019/backbone,ereddate/backbone,sumyfly/backbone,oss-practice/backbone,kuychaco/backbone,batigoal1980/backbone_example,cgvarela/backbone,au-phiware/backbone,lastjune/backbone,lujocom/backbone,yawenl/backbone,sunday-star/backbone,ThisIsManta/Backbone,GerHobbelt/backbone,tgriesser/backbone,luffy94608/backbone,neocotic/hipbone,vincent1988/backbone,GrimDerp/backbone,jewsroch/backbone,Flip120/backbone,jashkenas/backbone,nvoron23/backbone,gougouGet/backbone,zhangdimelody/backbone,cailong1028/backbone,wxmfront/backbone,Aplopio/backbone,fanhc019/backbone,7213/backbone,Khan/backbone,closeio/backbone,sueyeh/backbone,jstrimpel/backbone,huanglp47/backbone,ntgn81/backbone,elancom/backbone,embarknow/backbone,howtolearntocode/backbone,ThiagoGarciaAlves/backbone,ppker/backbone,FormidableLabs/backbone,wakanpaladin/mybackbone,JesseQin/backbone,honger05/backbone,rashmisajjan/backbone,jordansexton/backboner,gdi2290/backbone,tibic/backbone,jewsroch/backbone,dillonforrest/backbone-df,nikolas/backbone,webcoding/backbone,jasoncbautista/backboneX,alekskorolev/lightbones,tzkKrbys/backbone,ywenjinlin/backbone,dak/backbone,dcheepurupalli/backbone,Bug2014/backbone,Sachin-Ganesh/backbone,hugohua/backbone,leimd/backbone,guahanweb/backbone,zhangdimelody/backbone,platinumazure/backbone,tadwhitaker/backbone,paulfalgout/backbone,tzkKrbys/backbone,premkumargithub/backbone,wjb12/backbone,closeio/backbone,youprofit/backbone,craigmichaelmartin/backbone,LovelyL25/backbone.js,ntgn81/backbone,maryrosecook/backbone-df,vin100bk/backbone,Bug2014/backbone,GrimDerp/backbone,virtru-components/backbone,pandoraui/backbone,darrrk/backbone,Khan/backbone,honger05/backbone,gougouGet/backbone,tadwhitaker/backbone,antoniogarrote/backbone,nikolas/backbone,webcoding/backbone,amdjs/backbone,jridgewell/backbone,dillonforrest/backbone-df,jmeas/backbone,GerHobbelt/backbone,Sachin-Ganesh/backbone,Krasnyanskiy/backbone,akre54/backbone,aihua/backbone,youprofit/backbone,craigmichaelmartin/backbone,jungjung917/backbone,zdespolit/backbone,Flip120/backbone,mmolinastudio/backbone,lujocom/backbone,ereddate/backbone,Diwahars/backbone,batigoal1980/backbone_example,ohbarye/backbone,dak/backbone,rjz/boneless,mmolinastudio/backbone,ohbarye/backbone,Krasnyanskiy/backbone,Connectlegendary/backbone,embarknow/backbone,sitexa/backbone,neocotic/hipbone,heroazure/backbone,platinumazure/backbone,guahanweb/backbone