use Proxy instead of undefined -- we already dropped support for 7.6
use Proxy instead of undefined -- we already dropped support for 7.6

Reviewers: austin, goldfire, bgamari

Reviewed By: bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D1363

AlexanderPankiv/ghc,sdiehl/ghc,olsner/ghc,da-x/ghc,elieux/ghc,sdiehl/ghc,oldmanmike/ghc,mcschroeder/ghc,oldmanmike/ghc,shlevy/ghc,mettekou/ghc,elieux/ghc,nushio3/ghc,oldmanmike/ghc,siddhanathan/ghc,oldmanmike/ghc,sdiehl/ghc,snoyberg/ghc,sdiehl/ghc,vTurbine/ghc,nushio3/ghc,mcschroeder/ghc,elieux/ghc,mettekou/ghc,tjakway/ghcjvm,da-x/ghc,vikraman/ghc,AlexanderPankiv/ghc,tjakway/ghcjvm,nushio3/ghc,vTurbine/ghc,sgillespie/ghc,vikraman/ghc,da-x/ghc,gridaphobe/ghc,vTurbine/ghc,vTurbine/ghc,siddhanathan/ghc,mettekou/ghc,mcschroeder/ghc,mettekou/ghc,AlexanderPankiv/ghc,oldmanmike/ghc,olsner/ghc,ezyang/ghc,vTurbine/ghc,AlexanderPankiv/ghc,GaloisInc/halvm-ghc,snoyberg/ghc,GaloisInc/halvm-ghc,sgillespie/ghc,olsner/ghc,tjakway/ghcjvm,olsner/ghc,vikraman/ghc,olsner/ghc,elieux/ghc,gridaphobe/ghc,nushio3/ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,nushio3/ghc,GaloisInc/halvm-ghc,olsner/ghc,gridaphobe/ghc,sdiehl/ghc,vikraman/ghc,sdiehl/ghc,da-x/ghc,mettekou/ghc,ezyang/ghc,mcschroeder/ghc,AlexanderPankiv/ghc,AlexanderPankiv/ghc,vikraman/ghc,ezyang/ghc,shlevy/ghc,gridaphobe/ghc,nushio3/ghc,siddhanathan/ghc,mettekou/ghc,mettekou/ghc,ezyang/ghc,siddhanathan/ghc,mcschroeder/ghc,snoyberg/ghc,snoyberg/ghc,siddhanathan/ghc,gridaphobe/ghc,snoyberg/ghc,snoyberg/ghc,vTurbine/ghc,elieux/ghc,tjakway/ghcjvm,tjakway/ghcjvm,sgillespie/ghc,sgillespie/ghc,ezyang/ghc,gridaphobe/ghc,tjakway/ghcjvm,tjakway/ghcjvm,da-x/ghc,nushio3/ghc,vikraman/ghc,ezyang/ghc,oldmanmike/ghc,ezyang/ghc,mcschroeder/ghc,gridaphobe/ghc,shlevy/ghc,shlevy/ghc,GaloisInc/halvm-ghc,shlevy/ghc,da-x/ghc,sgillespie/ghc,da-x/ghc,vikraman/ghc,elieux/ghc,snoyberg/ghc,mcschroeder/ghc,siddhanathan/ghc,elieux/ghc,GaloisInc/halvm-ghc,sdiehl/ghc,sgillespie/ghc,shlevy/ghc,vTurbine/ghc,olsner/ghc,sgillespie/ghc,shlevy/ghc,AlexanderPankiv/ghc,siddhanathan/ghc,oldmanmike/ghc