!!! resolution failed
!!! request ( ( ('repo.livefs',) EqualityMatch: =False || ( ('category',) == virtual && ('package_is_real',) EqualityMatch: =False ) ) && =dev-ml/core_kernel-0.16.0 ), mode none
!!! trying dev-ml/core_kernel-0.16.0
!!!   request dev-ml/core:0/0.16, mode depend
!!!   trying dev-ml/core-0.16.1
!!!     request dev-ml/base:0/0.16, mode depend
!!!     trying dev-ml/base-0.16.3-r1
!!!       request =dev-ml/sexplib0-0.16*:=[ocamlopt], mode depend
!!!       trying dev-ml/sexplib0-0.16.0
!!!         failed due to failed inserting: [<PackageWrapper pkg=<<class 'pkgcore.ebuild.ebuild_src.package'> cpv='dev-ml/sexplib0-0.17.0-r2' @0x10dc81e90> wrapped='use' @0x10dcd5dd0>]
!!!       removing choices involving =dev-ml/sexplib0-0.16*:=[ocamlopt]
!!!     removing choices involving dev-ml/base:0/0.16
!!!   removing choices involving dev-ml/core:0/0.16

Failures encountered:
!!! failed '( ( ('repo.livefs',) EqualityMatch: =False || ( ('category',) == virtual && ('package_is_real',) EqualityMatch: =False ) ) && =dev-ml/core_kernel-0.16.0 )'
potentials:
repo gentoo: [ ebuild src: dev-ml/core_kernel-0.16.0 ]