error during sync: dev-lang/mono-9999::dotnet EAPI 5 not supported

[fluffynuts]

As per the title, error happens during sync, full output is:

Calculating dependencies - * ERROR: dev-lang/mono-9999::dotnet failed (depend phase):
 *   toolchain-funcs: EAPI 5 not supported
 * 
 * Call stack:
 *                ebuild.sh, line 618:  Called source '/var/db/repos/dotnet/dev-lang/mono/mono-9999.ebuild'
 *         mono-9999.ebuild, line   7:  Called inherit 'linux-info' 'mono-env' 'flag-o-matic' 'pax-utils' 'autotools' 'git-r3'
 *                ebuild.sh, line 298:  Called __qa_source '/usr/portage/eclass/linux-info.eclass'
 *                ebuild.sh, line 114:  Called source '/usr/portage/eclass/linux-info.eclass'
 *        linux-info.eclass, line 135:  Called inherit 'toolchain-funcs'
 *                ebuild.sh, line 298:  Called __qa_source '/usr/portage/eclass/toolchain-funcs.eclass'
 *                ebuild.sh, line 114:  Called source '/usr/portage/eclass/toolchain-funcs.eclass'
 *   toolchain-funcs.eclass, line  18:  Called die
 * The specific snippet of code:
 *      *) die "${ECLASS}: EAPI ${EAPI:-0} not supported" ;;
 * 
 * If you need support, post the output of `emerge --info '=dev-lang/mono-9999::dotnet'`,
 * the complete build log and the output of `emerge -pqv '=dev-lang/mono-9999::dotnet'`.
 * Working directory: '/usr/lib/python3.10/site-packages'
 * S: '/var/tmp/portage/dev-lang/mono-9999/work/mono-9999'

[Irets]

I can confirm. What happened to the non-9999 ebuilds of dev-lang/mono?

/var/db/repos/dotnet/dev-lang/mono/:
total 8
drwxr-xr-x 3 root root 1024 Nov 13  2021 .
drwxr-xr-x 5 root root 1024 Nov 13  2021 ..
drwxr-xr-x 2 root root 1024 Nov 13  2021 files
-rw-r--r-- 1 root root  967 Nov 13  2021 metadata.xml
-rw-r--r-- 1 root root 3173 Nov 13  2021 mono-9999.ebuild

/var/db/repos/dotnet/dev-lang/mono/files:
total 25
drwxr-xr-x 2 root root 1024 Nov 13  2021 .
drwxr-xr-x 3 root root 1024 Nov 13  2021 ..
-rw-r--r-- 1 root root 1174 Nov 13  2021 add_missing_vb_portable_targets.patch
-rw-r--r-- 1 root root  687 Nov 13  2021 autofac.patch
-rw-r--r-- 1 root root  551 Nov 13  2021 fix-for-bug36724.patch
-rw-r--r-- 1 root root 2182 Nov 13  2021 fix-for-GitExtensions-issue-2710-another-resolution.patch
-rw-r--r-- 1 root root 1353 Nov 13  2021 fix-for-GitExtensions-issue-2710.patch
-rw-r--r-- 1 root root  620 Nov 13  2021 mono-3.2.1-mdoc-fix.patch
-rw-r--r-- 1 root root 1149 Nov 13  2021 mono-4.0.2.5-fix-decimal-ms-on-big-endian.patch
-rw-r--r-- 1 root root  552 Nov 13  2021 mono-4.0.2.5-fix-mono-dis-makefile-am-when-without-sgen.patch
-rw-r--r-- 1 root root 2550 Nov 13  2021 mono-4.0.2.5-fix-ppc-atomic-add-i4.patch
-rw-r--r-- 1 root root  751 Nov 13  2021 mono-5.0.1.1-x86_32.patch
-rw-r--r-- 1 root root 2745 Nov 13  2021 mono-5.10.0.179-ncurses61.patch
-rw-r--r-- 1 root root  676 Nov 13  2021 systemweb3.patch
-rw-r--r-- 1 root root 1267 Nov 13  2021 try-catch.patch

[thesamesam]

There are mono ebuilds in ::gentoo which work.