idUnfoldingVars :: Id -> VarSet
-- Produce free vars for an unfolding, but NOT for an ordinary
-- (non-inline) unfolding, since it is a dup of the rhs
-- and we'll get exponential behaviour if we look at both unf and rhs!
-- But do look at the *real* unfolding, even for loop breakers, else
-- we might get out-of-scope variables
idUnfoldingVars id = fvVarSet $ idUnfoldingFVs id
idUnfoldingVars :: Id -> VarSet
idUnfoldingVars id = fvVarSet $ idUnfoldingFVs id
idUnfoldingVars id = fvVarSet $ idUnfoldingFVs id