Use toString on attrs having outPath

checkmate.nix

@@ -194,6 +194,15 @@ in
           expected = "world";
         };
 
+        import-tree."test take as arg anything path convertible" = {
+          expr = lit.leafs [
+            {
+              outPath = ./tree/modules/hello-world;
+            }
+          ];
+          expected = [ ./tree/modules/hello-world/mod.nix ];
+        };
+
         import-tree."test can take other import-trees as if they were paths" = {
           expr = (lit.filter (lib.hasInfix "mod")).leafs [
             (it.addPath ./tree/modules/hello-option)

default.nix

@@ -33,6 +33,8 @@ let
             x:
             if isImportTree x then
               treeFiles x
+            else if hasOutPath x then
+              listFilesRecursive x.outPath
             else if lib.pathIsDirectory x then
               lib.filesystem.listFilesRecursive x
             else
@@ -69,6 +71,8 @@ let
     attrs: k: f:
     attrs // { ${k} = f attrs.${k}; };
 
+  hasOutPath = and (x: x ? outPath) builtins.isAttrs;
+
   isImportTree = and (x: x ? __config.__functor) builtins.isAttrs;
 
   inModuleEval = and (x: x ? options) builtins.isAttrs;