auto merge of #933 : saneyuki/servo/is_some, r=jdm
auto merge of #933 : saneyuki/servo/is_some, r=jdm

Fix #919 

shrenikgala/servo,Adenilson/prototype-viewing-distance,dvberkel/servo,shrenikgala/servo,zhangjunlei26/servo,dmarcos/servo,shrenikgala/servo,mrobinson/servo,indykish/servo,eddyb/servo,s142857/servo,walac/servo,nnethercote/servo,ConnorGBrewster/servo,pcwalton/servo,splav/servo,eddyb/servo,meh/servo,avadacatavra/servo,dagnir/servo,kindersung/servo,samfoo/servo,bfrohs/servo,dhananjay92/servo,runarberg/servo,fiji-flo/servo,froydnj/servo,chotchki/servo,dati91/servo,WriterOfAlicrow/servo,echochamber/servo,luniv/servo,mattnenterprise/servo,juzer10/servo,michaelwu/servo,dvberkel/servo,anthgur/servo,snf/servo,paulrouget/servo,mbrubeck/servo,g-k/servo,saneyuki/servo,szeged/servo,snf/servo,ConnorGBrewster/servo,hyowon/servo,dati91/servo,paulrouget/servo,thiagopnts/servo,dsandeephegde/servo,DominoTree/servo,samfoo/servo,sadmansk/servo,Aalhad/CanvasRenderingContext2DMozilla,bjwbell/servo,peterjoel/servo,cbrewster/servo,AnthonyBroadCrawford/servo,GyrosOfWar/servo,snf/servo,fiji-flo/servo,youprofit/servo,emilio/servo,fiji-flo/servo,larsbergstrom/servo,GyrosOfWar/servo,dhananjay92/servo,dati91/servo,splav/servo,jgraham/servo,indykish/servo,aweinstock314/servo,evilpie/servo,echochamber/servo,canaltinova/servo,DominoTree/servo,luniv/servo,evilpie/servo,juzer10/servo,runarberg/servo,szeged/servo,wpgallih/servo,srbhklkrn/SERVOENGINE,mdibaiee/servo,boghison/servo,ryancanhelpyou/servo,froydnj/servo,nerith/servo,nnethercote/servo,larsbergstrom/servo,saneyuki/servo,indykish/servo,indykish/servo,larsbergstrom/servo,upsuper/servo,SimonSapin/servo,aidanhs/servo,dsandeephegde/servo,juzer10/servo,WriterOfAlicrow/servo,akosel/servo,s142857/servo,paulrouget/servo,GyrosOfWar/servo,aweinstock314/servo,SimonSapin/servo,jdramani/servo,rixrix/servo,Shraddha512/servo,Aalhad/CanvasRenderingContext2DMozilla,Shraddha512/servo,wartman4404/servo,RenaudParis/servo,rnestler/servo,huonw/servo,indykish/servo,thiagopnts/servo,jlegendary/servo,dmarcos/servo,zentner-kyle/servo,hyowon/servo,wartman4404/servo,ruud-v-a/servo,boghison/servo,j3parker/servo,wartman4404/servo,upsuper/servo,aidanhs/servo,rentongzhang/servo,metajack/servo,paulrouget/servo,rixrix/servo,zhangjunlei26/servo,walac/servo,dvberkel/servo,ryancanhelpyou/servo,hyowon/servo,zentner-kyle/servo,KiChjang/servo,nnethercote/servo,rentongzhang/servo,aidanhs/servo,tafia/servo,wartman4404/servo,mukilan/servo,WriterOfAlicrow/servo,pyecs/servo,youprofit/servo,evilpie/servo,pyecs/servo,boghison/servo,A-deLuna/servo,nnethercote/servo,cbrewster/servo,zentner-kyle/servo,karlito40/servo,dhananjay92/servo,bjwbell/servo,A-deLuna/servo,pyfisch/servo,karlito40/servo,rentongzhang/servo,mattnenterprise/servo,Aalhad/CanvasRenderingContext2DMozilla,huonw/servo,huonw/servo,g-k/servo,peterjoel/servo,jdramani/servo,caldwell/servo,emilio/servo,anthgur/servo,mattnenterprise/servo,anthgur/servo,huonw/servo,seanmonstar/servo,youprofit/servo,AnthonyBroadCrawford/servo,runarberg/servo,avadacatavra/servo,GreenRecycleBin/servo,nnethercote/servo,emilio/servo,rentongzhang/servo,zhangjunlei26/servo,froydnj/servo,dati91/servo,notriddle/servo,GreenRecycleBin/servo,jlegendary/servo,szeged/servo,akosel/servo,vks/servo,fiji-flo/servo,KiChjang/servo,jlegendary/servo,larsbergstrom/servo,brendandahl/servo,mukilan/servo,wpgallih/servo,pyfisch/servo,deokjinkim/servo,chotchki/servo,tafia/servo,saratang/servo,paulrouget/servo,chotchki/servo,dhananjay92/servo,kindersung/servo,codemac/servo,mt2d2/servo,ryancanhelpyou/servo,thiagopnts/servo,tschneidereit/servo,caldwell/servo,DominoTree/servo,DominoTree/servo,CJ8664/servo,chotchki/servo,youprofit/servo,jimberlage/servo,boghison/servo,peterjoel/servo,notriddle/servo,DominoTree/servo,nrc/servo,saneyuki/servo,shrenikgala/servo,boghison/servo,DominoTree/servo,pcwalton/servo,peterjoel/servo,pyecs/servo,tafia/servo,huonw/servo,steveklabnik/servo,splav/servo,boghison/servo,dmarcos/servo,tempbottle/servo,emilio/servo,karlito40/servo,wpgallih/servo,rnestler/servo,avadacatavra/servo,hyowon/servo,dhananjay92/servo,Adenilson/prototype-viewing-distance,nnethercote/servo,peterjoel/servo,pyfisch/servo,CJ8664/servo,saneyuki/servo,saneyuki/servo,mattnenterprise/servo,KiChjang/servo,aidanhs/servo,GreenRecycleBin/servo,bfrohs/servo,WriterOfAlicrow/servo,hyowon/servo,j3parker/servo,rixrix/servo,dati91/servo,bfrohs/servo,eddyb/servo,tschneidereit/servo,youprofit/servo,Adenilson/prototype-viewing-distance,karlito40/servo,pgonda/servo,indykish/servo,brendandahl/servo,karlito40/servo,cbrewster/servo,aidanhs/servo,sadmansk/servo,deokjinkim/servo,tafia/servo,chotchki/servo,codemac/servo,juzer10/servo,rentongzhang/servo,luniv/servo,seanmonstar/servo,AnthonyBroadCrawford/servo,ConnorGBrewster/servo,codemac/servo,tschneidereit/servo,mbrubeck/servo,jgraham/servo,fiji-flo/servo,mt2d2/servo,owaspjocur/servo,dagnir/servo,DominoTree/servo,CJ8664/servo,dati91/servo,saratang/servo,nrc/servo,aweinstock314/servo,emilio/servo,saratang/servo,Adenilson/prototype-viewing-distance,jimberlage/servo,huonw/servo,mrobinson/servo,caldwell/servo,cbrewster/servo,ruud-v-a/servo,Adenilson/prototype-viewing-distance,nrc/servo,ConnorGBrewster/servo,jlegendary/servo,saneyuki/servo,larsbergstrom/servo,echochamber/servo,jimberlage/servo,shrenikgala/servo,zhangjunlei26/servo,sadmansk/servo,mt2d2/servo,dagnir/servo,karlito40/servo,srbhklkrn/SERVOENGINE,splav/servo,luniv/servo,michaelwu/servo,srbhklkrn/SERVOENGINE,rixrix/servo,eddyb/servo,mdibaiee/servo,j3parker/servo,s142857/servo,mbrubeck/servo,michaelwu/servo,nick-thompson/servo,j3parker/servo,saneyuki/servo,peterjoel/servo,dvberkel/servo,nick-thompson/servo,paulrouget/servo,aweinstock314/servo,nerith/servo,jlegendary/servo,wpgallih/servo,DominoTree/servo,evilpie/servo,CJ8664/servo,ruud-v-a/servo,splav/servo,splav/servo,pcwalton/servo,brendandahl/servo,mbrubeck/servo,akosel/servo,szeged/servo,michaelwu/servo,ruud-v-a/servo,s142857/servo,codemac/servo,Aalhad/CanvasRenderingContext2DMozilla,GyrosOfWar/servo,runarberg/servo,pyfisch/servo,peterjoel/servo,samfoo/servo,eddyb/servo,s142857/servo,sadmansk/servo,zhangjunlei26/servo,notriddle/servo,akosel/servo,DominoTree/servo,luniv/servo,sadmansk/servo,WriterOfAlicrow/servo,notriddle/servo,canaltinova/servo,emilio/servo,caldwell/servo,paulrouget/servo,kindersung/servo,jlegendary/servo,larsbergstrom/servo,deokjinkim/servo,eddyb/servo,RenaudParis/servo,nick-thompson/servo,aweinstock314/servo,avadacatavra/servo,jimberlage/servo,pyecs/servo,walac/servo,rnestler/servo,upsuper/servo,mt2d2/servo,notriddle/servo,wartman4404/servo,g-k/servo,avadacatavra/servo,metajack/servo,splav/servo,thiagopnts/servo,zhangjunlei26/servo,caldwell/servo,CJ8664/servo,dsandeephegde/servo,jgraham/servo,evilpie/servo,jdramani/servo,KiChjang/servo,mt2d2/servo,g-k/servo,brendandahl/servo,pcwalton/servo,echochamber/servo,splav/servo,wartman4404/servo,metajack/servo,AnthonyBroadCrawford/servo,mukilan/servo,tafia/servo,KiChjang/servo,vks/servo,brendandahl/servo,pcwalton/servo,jgraham/servo,ConnorGBrewster/servo,mattnenterprise/servo,deokjinkim/servo,rixrix/servo,dmarcos/servo,nrc/servo,thiagopnts/servo,WriterOfAlicrow/servo,tempbottle/servo,j3parker/servo,RenaudParis/servo,walac/servo,peterjoel/servo,juzer10/servo,meh/servo,huonw/servo,jimberlage/servo,mbrubeck/servo,steveklabnik/servo,srbhklkrn/SERVOENGINE,deokjinkim/servo,kindersung/servo,dvberkel/servo,Shraddha512/servo,pyfisch/servo,akosel/servo,mrobinson/servo,pyfisch/servo,srbhklkrn/SERVOENGINE,zhangjunlei26/servo,srbhklkrn/SERVOENGINE,emilio/servo,Adenilson/prototype-viewing-distance,Adenilson/prototype-viewing-distance,wpgallih/servo,vks/servo,samfoo/servo,pgonda/servo,zentner-kyle/servo,A-deLuna/servo,tschneidereit/servo,KiChjang/servo,indykish/servo,anthgur/servo,canaltinova/servo,nick-thompson/servo,owaspjocur/servo,shrenikgala/servo,tafia/servo,chotchki/servo,canaltinova/servo,jimberlage/servo,KiChjang/servo,meh/servo,larsbergstrom/servo,shrenikgala/servo,luniv/servo,sadmansk/servo,upsuper/servo,tschneidereit/servo,AnthonyBroadCrawford/servo,Aalhad/CanvasRenderingContext2DMozilla,wartman4404/servo,mukilan/servo,canaltinova/servo,pgonda/servo,avadacatavra/servo,steveklabnik/servo,GreenRecycleBin/servo,sadmansk/servo,snf/servo,paulrouget/servo,deokjinkim/servo,vks/servo,jdramani/servo,cbrewster/servo,notriddle/servo,vks/servo,mrobinson/servo,j3parker/servo,GyrosOfWar/servo,evilpie/servo,dmarcos/servo,dhananjay92/servo,youprofit/servo,eddyb/servo,dagnir/servo,pyecs/servo,steveklabnik/servo,GreenRecycleBin/servo,karlito40/servo,szeged/servo,hyowon/servo,walac/servo,jimberlage/servo,szeged/servo,RenaudParis/servo,notriddle/servo,aidanhs/servo,wpgallih/servo,ConnorGBrewster/servo,dati91/servo,dsandeephegde/servo,metajack/servo,steveklabnik/servo,nnethercote/servo,anthgur/servo,walac/servo,nerith/servo,owaspjocur/servo,fiji-flo/servo,hyowon/servo,dsandeephegde/servo,wpgallih/servo,froydnj/servo,avadacatavra/servo,bfrohs/servo,indykish/servo,dsandeephegde/servo,rentongzhang/servo,SimonSapin/servo,CJ8664/servo,nnethercote/servo,akosel/servo,srbhklkrn/SERVOENGINE,A-deLuna/servo,ConnorGBrewster/servo,vks/servo,emilio/servo,pgonda/servo,notriddle/servo,tempbottle/servo,fiji-flo/servo,seanmonstar/servo,codemac/servo,larsbergstrom/servo,AnthonyBroadCrawford/servo,nick-thompson/servo,snf/servo,rnestler/servo,deokjinkim/servo,jdramani/servo,szeged/servo,saratang/servo,wpgallih/servo,pyfisch/servo,paulrouget/servo,dhananjay92/servo,meh/servo,rixrix/servo,sadmansk/servo,pyecs/servo,mattnenterprise/servo,pyecs/servo,larsbergstrom/servo,jgraham/servo,mukilan/servo,ruud-v-a/servo,mattnenterprise/servo,evilpie/servo,KiChjang/servo,jimberlage/servo,samfoo/servo,g-k/servo,pgonda/servo,rixrix/servo,rixrix/servo,CJ8664/servo,bjwbell/servo,upsuper/servo,GreenRecycleBin/servo,bfrohs/servo,nerith/servo,nrc/servo,owaspjocur/servo,thiagopnts/servo,brendandahl/servo,splav/servo,seanmonstar/servo,cbrewster/servo,RenaudParis/servo,paulrouget/servo,bfrohs/servo,bjwbell/servo,michaelwu/servo,g-k/servo,runarberg/servo,dmarcos/servo,boghison/servo,owaspjocur/servo,zentner-kyle/servo,anthgur/servo,GyrosOfWar/servo,notriddle/servo,Aalhad/CanvasRenderingContext2DMozilla,fiji-flo/servo,jgraham/servo,saratang/servo,mdibaiee/servo,owaspjocur/servo,DominoTree/servo,echochamber/servo,emilio/servo,samfoo/servo,indykish/servo,zhangjunlei26/servo,thiagopnts/servo,caldwell/servo,mdibaiee/servo,pgonda/servo,GreenRecycleBin/servo,jgraham/servo,szeged/servo,KiChjang/servo,steveklabnik/servo,dsandeephegde/servo,ryancanhelpyou/servo,echochamber/servo,canaltinova/servo,seanmonstar/servo,GyrosOfWar/servo,ryancanhelpyou/servo,codemac/servo,A-deLuna/servo,dagnir/servo,froydnj/servo,rentongzhang/servo,jimberlage/servo,jlegendary/servo,SimonSapin/servo,pyfisch/servo,caldwell/servo,g-k/servo,bjwbell/servo,KiChjang/servo,aweinstock314/servo,mbrubeck/servo,cbrewster/servo,nnethercote/servo,mt2d2/servo,thiagopnts/servo,nick-thompson/servo,snf/servo,tempbottle/servo,dati91/servo,avadacatavra/servo,evilpie/servo,A-deLuna/servo,mdibaiee/servo,steveklabnik/servo,pyfisch/servo,upsuper/servo,rnestler/servo,RenaudParis/servo,aweinstock314/servo,Shraddha512/servo,saratang/servo,meh/servo,zhangjunlei26/servo,szeged/servo,youprofit/servo,AnthonyBroadCrawford/servo,mattnenterprise/servo,Shraddha512/servo,CJ8664/servo,peterjoel/servo,SimonSapin/servo,aidanhs/servo,juzer10/servo,runarberg/servo,saneyuki/servo,mt2d2/servo,rnestler/servo,kindersung/servo,kindersung/servo,dsandeephegde/servo,ryancanhelpyou/servo,rnestler/servo,jdramani/servo,dagnir/servo,upsuper/servo,larsbergstrom/servo,mrobinson/servo,saneyuki/servo,nnethercote/servo,saratang/servo,juzer10/servo,Shraddha512/servo,nerith/servo,seanmonstar/servo,wpgallih/servo,tschneidereit/servo,A-deLuna/servo,snf/servo,szeged/servo,nerith/servo,akosel/servo,canaltinova/servo,bjwbell/servo,dvberkel/servo,pgonda/servo,mbrubeck/servo,bjwbell/servo,saneyuki/servo,WriterOfAlicrow/servo,vks/servo,SimonSapin/servo,ryancanhelpyou/servo,walac/servo,notriddle/servo,kindersung/servo,pcwalton/servo,mrobinson/servo,froydnj/servo,j3parker/servo,mdibaiee/servo,meh/servo,canaltinova/servo,samfoo/servo,meh/servo,peterjoel/servo,nrc/servo,mbrubeck/servo,nick-thompson/servo,dmarcos/servo,pyfisch/servo,evilpie/servo,GreenRecycleBin/servo,dvberkel/servo,Shraddha512/servo,mukilan/servo,echochamber/servo,metajack/servo,brendandahl/servo,tempbottle/servo,SimonSapin/servo,michaelwu/servo,emilio/servo,rnestler/servo,rixrix/servo,anthgur/servo,RenaudParis/servo,eddyb/servo,tafia/servo,ConnorGBrewster/servo,mdibaiee/servo,zentner-kyle/servo,nrc/servo,cbrewster/servo,nerith/servo,jdramani/servo,dagnir/servo,luniv/servo,metajack/servo,upsuper/servo,GreenRecycleBin/servo,anthgur/servo,s142857/servo,ruud-v-a/servo,tempbottle/servo,tschneidereit/servo,codemac/servo,s142857/servo,zentner-kyle/servo,tempbottle/servo,runarberg/servo,SimonSapin/servo,splav/servo