error:
       … while calling the 'throw' builtin
         at /pwd/in.nix:6:1:
            5| in
            6| throw set.inner
             | ^
            7|

       … while evaluating the attribute 'inner'
         at /pwd/in.nix:3:5:
            2|   set = {
            3|     inner = throw "nested throw";
             |     ^
            4|   };

       … caused by explicit throw
         at /pwd/in.nix:3:13:
            2|   set = {
            3|     inner = throw "nested throw";
             |             ^
            4|   };

       error: nested throw