Install this version:
emerge -a =dev-haskell/fgl-5.8.3.1
If this version is masked, you can unmask it using the autounmask tool or standard emerge options:
autounmask =dev-haskell/fgl-5.8.3.1
Or alternatively:
emerge --autounmask-write -a =dev-haskell/fgl-5.8.3.1
# Copyright 1999-2026 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2
EAPI=8
# ebuild generated by hackport 0.9.1.0
CABAL_FEATURES="lib profile haddock hoogle hscolour test-suite"
inherit haskell-cabal
DESCRIPTION="Martin Erwig's Functional Graph Library"
HOMEPAGE="https://hackage.haskell.org/package/fgl"
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
test? ( >=dev-haskell/hspec-2.1 <dev-haskell/hspec-2.12
>=dev-haskell/quickcheck-2.8 <dev-haskell/quickcheck-2.17 )
"
>=dev-lang/ghc-9.0.2:= >=dev-haskell/cabal-3.4.1.0 test? ( >=dev-haskell/hspec-2.1 <dev-haskell/hspec-2.12 >=dev-haskell/quickcheck-2.8 <dev-haskell/quickcheck-2.17 )
>=dev-lang/ghc-9.0.2:=