Auto merge of #17743 - emilio:assert-properly, r=heycam
Auto merge of #17743 - emilio:assert-properly, r=heycam

stylo: Assert our stuff properly.

cbrewster/servo,eddyb/servo,fiji-flo/servo,nnethercote/servo,ConnorGBrewster/servo,cbrewster/servo,mbrubeck/servo,rnestler/servo,larsbergstrom/servo,peterjoel/servo,SimonSapin/servo,jimberlage/servo,mattnenterprise/servo,ConnorGBrewster/servo,cbrewster/servo,avadacatavra/servo,eddyb/servo,sadmansk/servo,ConnorGBrewster/servo,DominoTree/servo,splav/servo,CJ8664/servo,SimonSapin/servo,peterjoel/servo,larsbergstrom/servo,DominoTree/servo,upsuper/servo,CJ8664/servo,emilio/servo,splav/servo,SimonSapin/servo,emilio/servo,mbrubeck/servo,splav/servo,emilio/servo,DominoTree/servo,thiagopnts/servo,rnestler/servo,thiagopnts/servo,dati91/servo,larsbergstrom/servo,szeged/servo,notriddle/servo,pyfisch/servo,szeged/servo,SimonSapin/servo,fiji-flo/servo,sadmansk/servo,CJ8664/servo,dsandeephegde/servo,fiji-flo/servo,splav/servo,mbrubeck/servo,paulrouget/servo,rnestler/servo,dsandeephegde/servo,splav/servo,emilio/servo,dati91/servo,SimonSapin/servo,ConnorGBrewster/servo,mattnenterprise/servo,fiji-flo/servo,saneyuki/servo,CJ8664/servo,fiji-flo/servo,szeged/servo,nnethercote/servo,nnethercote/servo,pyfisch/servo,saneyuki/servo,upsuper/servo,notriddle/servo,canaltinova/servo,pyfisch/servo,KiChjang/servo,KiChjang/servo,DominoTree/servo,eddyb/servo,canaltinova/servo,nnethercote/servo,fiji-flo/servo,jimberlage/servo,dsandeephegde/servo,emilio/servo,saneyuki/servo,notriddle/servo,avadacatavra/servo,mattnenterprise/servo,pyfisch/servo,mbrubeck/servo,larsbergstrom/servo,notriddle/servo,fiji-flo/servo,rnestler/servo,dati91/servo,jimberlage/servo,cbrewster/servo,emilio/servo,dati91/servo,canaltinova/servo,canaltinova/servo,ConnorGBrewster/servo,szeged/servo,ConnorGBrewster/servo,cbrewster/servo,dsandeephegde/servo,KiChjang/servo,saneyuki/servo,szeged/servo,nnethercote/servo,pyfisch/servo,dati91/servo,paulrouget/servo,thiagopnts/servo,peterjoel/servo,avadacatavra/servo,saneyuki/servo,mbrubeck/servo,paulrouget/servo,peterjoel/servo,saneyuki/servo,paulrouget/servo,thiagopnts/servo,splav/servo,splav/servo,szeged/servo,jimberlage/servo,CJ8664/servo,thiagopnts/servo,paulrouget/servo,fiji-flo/servo,pyfisch/servo,dati91/servo,KiChjang/servo,larsbergstrom/servo,canaltinova/servo,SimonSapin/servo,larsbergstrom/servo,eddyb/servo,KiChjang/servo,cbrewster/servo,upsuper/servo,notriddle/servo,nnethercote/servo,ConnorGBrewster/servo,sadmansk/servo,rnestler/servo,saneyuki/servo,thiagopnts/servo,mbrubeck/servo,dsandeephegde/servo,thiagopnts/servo,canaltinova/servo,anthgur/servo,anthgur/servo,emilio/servo,mbrubeck/servo,CJ8664/servo,jimberlage/servo,pyfisch/servo,peterjoel/servo,peterjoel/servo,mattnenterprise/servo,anthgur/servo,emilio/servo,upsuper/servo,rnestler/servo,notriddle/servo,KiChjang/servo,sadmansk/servo,notriddle/servo,splav/servo,cbrewster/servo,saneyuki/servo,szeged/servo,peterjoel/servo,dsandeephegde/servo,sadmansk/servo,ConnorGBrewster/servo,upsuper/servo,pyfisch/servo,eddyb/servo,larsbergstrom/servo,KiChjang/servo,nnethercote/servo,avadacatavra/servo,DominoTree/servo,splav/servo,mbrubeck/servo,avadacatavra/servo,sadmansk/servo,avadacatavra/servo,paulrouget/servo,anthgur/servo,sadmansk/servo,DominoTree/servo,jimberlage/servo,szeged/servo,DominoTree/servo,peterjoel/servo,KiChjang/servo,anthgur/servo,szeged/servo,larsbergstrom/servo,canaltinova/servo,eddyb/servo,rnestler/servo,notriddle/servo,paulrouget/servo,CJ8664/servo,jimberlage/servo,dsandeephegde/servo,emilio/servo,canaltinova/servo,CJ8664/servo,dati91/servo,paulrouget/servo,notriddle/servo,peterjoel/servo,larsbergstrom/servo,rnestler/servo,cbrewster/servo,larsbergstrom/servo,emilio/servo,anthgur/servo,eddyb/servo,saneyuki/servo,jimberlage/servo,DominoTree/servo,peterjoel/servo,avadacatavra/servo,mattnenterprise/servo,nnethercote/servo,saneyuki/servo,paulrouget/servo,SimonSapin/servo,splav/servo,sadmansk/servo,anthgur/servo,szeged/servo,upsuper/servo,upsuper/servo,thiagopnts/servo,nnethercote/servo,paulrouget/servo,avadacatavra/servo,DominoTree/servo,notriddle/servo,dsandeephegde/servo,upsuper/servo,mattnenterprise/servo,pyfisch/servo,mattnenterprise/servo,DominoTree/servo,SimonSapin/servo,nnethercote/servo,jimberlage/servo,anthgur/servo,KiChjang/servo,mattnenterprise/servo,eddyb/servo,dati91/servo,pyfisch/servo,KiChjang/servo