in job ‘aarch64-darwin’:
error:
       … while evaluating the attribute 'hydraJobs'
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/outputs.nix:41:11:
           40|   inherit devShells;
           41|   inherit hydraJobs;
             |           ^
           42| }

       … from call site
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/outputs.nix:32:15:
           31|
           32|   hydraJobs = utils.flattenDerivationTree "-" hydraJobsPerSystem.${system};
             |               ^
           33|

       … while calling 'flattenDerivationTree'
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/utils.nix:5:38:
            4|
            5|   flattenDerivationTree = separator: set:
             |                                      ^
            6|     let

       … while calling the 'listToAttrs' builtin
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/utils.nix:20:7:
           19|       assert lib.typeOf set == "set";
           20|       lib.listToAttrs (flatten "" set);
             |       ^
           21|

       … from call site
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/utils.nix:20:24:
           19|       assert lib.typeOf set == "set";
           20|       lib.listToAttrs (flatten "" set);
             |                        ^
           21|

       … while calling 'flatten'
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/utils.nix:10:24:
            9|
           10|       flatten = name': value:
             |                        ^
           11|         let

       … while calling the 'concatLists' builtin
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/utils.nix:17:13:
           16|           else
           17|             lib.concatLists (lib.mapAttrsToList (recurse name) value);
             |             ^
           18|     in

       … while calling 'flatten'
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/utils.nix:10:24:
            9|
           10|       flatten = name': value:
             |                        ^
           11|         let

       … while calling the 'concatLists' builtin
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/utils.nix:17:13:
           16|           else
           17|             lib.concatLists (lib.mapAttrsToList (recurse name) value);
             |             ^
           18|     in

       … while calling 'flatten'
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/utils.nix:10:24:
            9|
           10|       flatten = name': value:
             |                        ^
           11|         let

       … while evaluating a branch condition
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/utils.nix:14:11:
           13|         in
           14|           if lib.isDerivation value || lib.typeOf value != "set" then
             |           ^
           15|             [{ inherit name value; }]

       … in the left operand of the OR (||) operator
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/utils.nix:14:37:
           13|         in
           14|           if lib.isDerivation value || lib.typeOf value != "set" then
             |                                     ^
           15|             [{ inherit name value; }]

       … from call site
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/utils.nix:14:14:
           13|         in
           14|           if lib.isDerivation value || lib.typeOf value != "set" then
             |              ^
           15|             [{ inherit name value; }]

       … while calling 'isDerivation'
         at /nix/store/dzwwydggypqg4p8r6if5zdaqyzhsxjkd-source/lib/attrsets.nix:1251:18:
         1250|   */
         1251|   isDerivation = value: value.type or null == "derivation";
             |                  ^
         1252|

       … from call site
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/outputs.nix:14:23:
           13|
           14|   devShells.default = mkShell "ghc966";
             |                       ^
           15|

       … while calling 'mkShell'
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/outputs.nix:12:13:
           11|
           12|   mkShell = ghc: import ./shell.nix { inherit inputs pkgs lib project utils ghc; };
             |             ^
           13|

       … from call site
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/outputs.nix:12:18:
           11|
           12|   mkShell = ghc: import ./shell.nix { inherit inputs pkgs lib project utils ghc; };
             |                  ^
           13|

       … while calling anonymous lambda
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/shell.nix:1:1:
            1| { inputs, pkgs, lib, project, utils, ghc }:
             | ^
            2|

       … from call site
         at /nix/store/hafb8kbrwp8r8y2hxypn2vp4zyr6m0pa-source/nix/shell.nix:79:11:
           78|
           79|   shell = project.shellFor {
             |           ^
           80|     name = "plinth-${project.args.compiler-nix-name}";

       … while calling 'shellFor'
         at /nix/store/9m3x6x4zwdcv4ai75kihk77fv6cfh71w-source/overlays/haskell.nix:836:24:
          835|             #
          836|             shellFor = extraArgs: (appendModule { shell = extraArgs; }).shell;
             |                        ^
          837|             shell = shellFor' rawProject.args.shell.crossPlatforms;

       … while evaluating the attribute 'shell'
         at /nix/store/9m3x6x4zwdcv4ai75kihk77fv6cfh71w-source/overlays/haskell.nix:837:13:
          836|             shellFor = extraArgs: (appendModule { shell = extraArgs; }).shell;
          837|             shell = shellFor' rawProject.args.shell.crossPlatforms;
             |             ^
          838|             shellFor' = crossPlatforms:

       … from call site
         at /nix/store/9m3x6x4zwdcv4ai75kihk77fv6cfh71w-source/overlays/haskell.nix:837:21:
          836|             shellFor = extraArgs: (appendModule { shell = extraArgs; }).shell;
          837|             shell = shellFor' rawProject.args.shell.crossPlatforms;
             |                     ^
          838|             shellFor' = crossPlatforms:

       … while calling 'shellFor''
         at /nix/store/9m3x6x4zwdcv4ai75kihk77fv6cfh71w-source/overlays/haskell.nix:838:25:
          837|             shell = shellFor' rawProject.args.shell.crossPlatforms;
          838|             shellFor' = crossPlatforms:
             |                         ^
          839|               let

       … while evaluating the attribute 'hsPkgs.shellFor'
         at /nix/store/9m3x6x4zwdcv4ai75kihk77fv6cfh71w-source/overlays/haskell.nix:707:44:
          706|               project = addProjectAndPackageAttrs rec {
          707|                   inherit (pkg-set.config) hsPkgs;
             |                                            ^
          708|                   inherit pkg-set;

       … while evaluating a branch condition
         at /nix/store/9m3x6x4zwdcv4ai75kihk77fv6cfh71w-source/overlays/haskell.nix:676:25:
          675|                 else project;
          676|               pkg-set = if plan-pkgs ? configurationError
             |                         ^
          677|                 then {

       … while evaluating a branch condition
         at /nix/store/9m3x6x4zwdcv4ai75kihk77fv6cfh71w-source/overlays/haskell.nix:661:27:
          660|               callProjectResults = callCabalProjectToNix config;
          661|               plan-pkgs = if !builtins.pathExists (callProjectResults.projectNix + "/plan.json")
             |                           ^
          662|                 then

       … in the argument of the not operator
         at /nix/store/9m3x6x4zwdcv4ai75kihk77fv6cfh71w-source/overlays/haskell.nix:661:31:
          660|               callProjectResults = callCabalProjectToNix config;
          661|               plan-pkgs = if !builtins.pathExists (callProjectResults.projectNix + "/plan.json")
             |                               ^
          662|                 then

       … while calling the 'pathExists' builtin
         at /nix/store/9m3x6x4zwdcv4ai75kihk77fv6cfh71w-source/overlays/haskell.nix:661:31:
          660|               callProjectResults = callCabalProjectToNix config;
          661|               plan-pkgs = if !builtins.pathExists (callProjectResults.projectNix + "/plan.json")
             |                               ^
          662|                 then

       … while realising the context of path '/nix/store/qk79lr9xqm3jyr954jhlicpcbv06f3s4-my-project-plan-to-nix-pkgs/plan.json'

       error: Cannot build '/nix/store/ak9znc63ww448l9lllqj3vnssypigf6s-my-project-plan-to-nix-pkgs.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/qk79lr9xqm3jyr954jhlicpcbv06f3s4-my-project-plan-to-nix-pkgs
         /nix/store/xkk9k2fj3yx80mwiljsyx2471jpskmkb-my-project-plan-to-nix-pkgs-freeze