pa_ppx_q_ast 0.07.02

Error log

The package failed to build. The error log from opam follows.

Opam plugin "depext" may require upgrading/reinstalling. Reinstall the plugin on the current switch? [Y/n] y
The following actions will be performed:
  - recompile opam-depext 1.2.1-1

<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
-> retrieved opam-depext.1.2.1-1  (cached)
-> removed   opam-depext.1.2.1-1
-> installed opam-depext.1.2.1-1
Done.

<><> opam-depext.1.2.1-1 installed successfully <><><><><><><><><><><><><><><><>
=> opam-depext is unnecessary when used with opam >= 2.1. Please use opam install directly instead
# Run eval $(opam env) to update the current shell environment

<><> Carrying on to "opam depext -viy pa_ppx_q_ast.0.07.02 yojson.2.1.2 uint.2.0.1 topkg.1.0.7 stdlib-shims.0.3.0 stdint.0.7.2 sexplib0.v0.16.0 seq.base rresult.0.7.0 result.1.5 pcre.7.5.0 pa_ppx_unique.0.07.02 pa_ppx_hashcons.0.07.02 pa_ppx.0.07.02 ounit2.2.2.7 ounit.2.2.7 ocamlgraph.2.1.0 ocamlfind.1.9.6 ocamlbuild.0.14.3 not-ocamlfind.0.12 logs.0.7.0 hashcons.1.3 fpath.0.7.3 fmt.0.9.0 dune-configurator.3.13.0 dune.3.13.0 csexp.1.5.2 cppo.1.6.9 conf-which.1 conf-pkg-config.3 conf-perl-string-shellquote.3 conf-perl-ipc-system-simple.3 conf-perl.2 conf-m4.1 conf-libpcre.1 conf-autoconf.0.1 camlp5.8.00.01 camlp-streams.5.0.1 bos.0.2.1 astring.0.8.5" 

You are using opam 2.1+, where external dependency handling has been integrated: consider calling opam directly, the 'depext' plugin interface is provided for backwards compatibility only
# Detecting depexts using vars: arch=x86_64, os=linux, os-distribution=debian, os-family=debian
[ERROR] No solution for pa_ppx_q_ast.0.07.02 & yojson.2.1.2 & uint.2.0.1 & topkg.1.0.7 & stdlib-shims.0.3.0 & stdint.0.7.2 & sexplib0.v0.16.0 & seq.base & rresult.0.7.0 & result.1.5 & pcre.7.5.0 & pa_ppx_unique.0.07.02 & pa_ppx_hashcons.0.07.02 & pa_ppx.0.07.02 & ounit2.2.2.7 & ounit.2.2.7 & ocamlgraph.2.1.0 & ocamlfind.1.9.6 & ocamlbuild.0.14.3 & not-ocamlfind.0.12 & logs.0.7.0 & hashcons.1.3 & fpath.0.7.3 & fmt.0.9.0 & dune-configurator.3.13.0 & dune.3.13.0 & csexp.1.5.2 & cppo.1.6.9 & conf-which.1 & conf-pkg-config.3 & conf-perl-string-shellquote.3 & conf-perl-ipc-system-simple.3 & conf-perl.2 & conf-m4.1 & conf-libpcre.1 & conf-autoconf.0.1 & camlp5.8.00.01 & camlp-streams.5.0.1 & bos.0.2.1 & astring.0.8.5:   * No agreement on the version of ocaml:
            - (invariant) -> ocaml-base-compiler = 4.12.1 -> ocaml = 4.12.1
            - pa_ppx = 0.07.02 -> ocaml (>= 4.10.0 & != 4.10.3 & < 4.11.2 | = 4.12.0)
            You can temporarily relax the switch invariant with `--update-invariant'


Command failed: opam --cli=2.1 list --readonly --external '--resolve=pa_ppx_q_ast.0.07.02,yojson.2.1.2,uint.2.0.1,topkg.1.0.7,stdlib-shims.0.3.0,stdint.0.7.2,sexplib0.v0.16.0,seq.base,rresult.0.7.0,result.1.5,pcre.7.5.0,pa_ppx_unique.0.07.02,pa_ppx_hashcons.0.07.02,pa_ppx.0.07.02,ounit2.2.2.7,ounit.2.2.7,ocamlgraph.2.1.0,ocamlfind.1.9.6,ocamlbuild.0.14.3,not-ocamlfind.0.12,logs.0.7.0,hashcons.1.3,fpath.0.7.3,fmt.0.9.0,dune-configurator.3.13.0,dune.3.13.0,csexp.1.5.2,cppo.1.6.9,conf-which.1,conf-pkg-config.3,conf-perl-string-shellquote.3,conf-perl-ipc-system-simple.3,conf-perl.2,conf-m4.1,conf-libpcre.1,conf-autoconf.0.1,camlp5.8.00.01,camlp-streams.5.0.1,bos.0.2.1,astring.0.8.5' returned 20