simplifyForceDefer (Let vdefs expr) = Let (simplifyVdef `fmap` vdefs) (simplifyForceDefer expr) where
    simplifyVdef (Vdef name expr) = Vdef name $ simplifyForceDefer expr
simplifyForceDefer (Let vdefs expr) = Let (simplifyVdef `fmap` vdefs) (simplifyForceDefer expr) where
    simplifyVdef (Vdef name expr) = Vdef name $ simplifyForceDefer expr
simplifyForceDefer (Let vdefs expr) = Let (simplifyVdef `fmap` vdefs) (simplifyForceDefer expr) where
    simplifyVdef (Vdef name expr) = Vdef name $ simplifyForceDefer expr