InstEnv
type DFunId
data OverlapFlag
data Instance
pprInstance
pprInstanceHdr
pprInstances
instanceHead
mkLocalInstance
mkImportedInstance
instanceDFunId
setInstanceDFunId
instanceRoughTcs
type InstEnv
emptyInstEnv
extendInstEnv
extendInstEnvList
lookupInstEnv
instEnvElts
classInstances
instanceBindFun
instanceCantMatch
roughMatchTcs