error: builder for '/nix/store/gj22iyvsikagh72v02790h0cv27l5fl6-ocaml4.12.0-fsq-unstable-2019-09-17.drv' failed with exit code 1;
       last 10 log lines:
       > 76 |                 psq = PsqK.adjust (fun p -> p - d) k t.psq;
       >                                        ^^^^^^^^^^^^^^^^
       > Error: This expression should not be a function, the expected type is PsqK.k
       >     ocamlopt lib/.fsq.objs/native/fsq.{cmx,o} (exit 2)
       > (cd _build/default && /nix/store/28nfnd70f17y2vd3rdihxx8ws3p6i1p2-ocaml-4.12.0/bin/ocamlopt.opt -w -40 -g -I lib/.fsq.objs/byte -I lib/.fsq.objs/native -I /nix/store/vbvl3ggqx588kwdwf380648almyp4wfq-ocaml4.12.0-psq-0.2.0/lib/ocaml/4.12.0/site-lib/psq -I /nix/store/vn9cb3m87klnrw8j1ax12dgxi10gdd16-ocaml4.12.0-seq-0.1/lib/ocaml/4.12.0/site-lib/seq -intf-suffix .ml -no-alias-deps -o lib/.fsq.objs/native/fsq.cmx -c -impl lib/fsq.ml)
       > File "lib/fsq.ml", line 76, characters 34-50:
       > 76 |                 psq = PsqK.adjust (fun p -> p - d) k t.psq;
       >                                        ^^^^^^^^^^^^^^^^
       > Error: This expression should not be a function, the expected type is PsqK.k