Install this version:
emerge -a =dev-haskell/data-default-0.8.0.1
If this version is masked, you can unmask it using the autounmask tool or standard emerge options:
autounmask =dev-haskell/data-default-0.8.0.1
Or alternatively:
emerge --autounmask-write -a =dev-haskell/data-default-0.8.0.1
# Copyright 1999-2026 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2
EAPI=8
# ebuild generated by hackport 0.9.0.0
CABAL_FEATURES="lib profile haddock hoogle hscolour test-suite"
inherit haskell-cabal
DESCRIPTION="A class for types with a default value"
HOMEPAGE="https://hackage.haskell.org/package/data-default"
LICENSE="BSD"
SLOT="0/${PV}"
KEYWORDS="~amd64 ~arm64 ~ppc64 ~riscv ~x86"
RDEPEND=">=dev-lang/ghc-9.0.2:=
"
DEPEND="${RDEPEND}
>=dev-haskell/cabal-3.4.1.0
"
>=dev-lang/ghc-9.0.2:= >=dev-haskell/cabal-3.4.1.0
>=dev-lang/ghc-9.0.2:=