lib.types: improve performance on attrsWith

    # base type for lazyAttrsOf and attrsOf

    attrsWith =

    {

      elemType,

      lazy ? false,

    }:

    let

      typeName = if lazy then "lazyAttrsOf" else "attrsOf";

      # Push down position info.

      pushPositions = map (def: mapAttrs (n: v: { inherit (def) file; value = v; }) def.value);

      binOp = lhs: rhs:

        let

          elemType = lhs.elemType.typeMerge rhs.elemType.functor;

          lazy =

            if lhs.lazy == rhs.lazy then

              lhs.lazy

            else

              null;

        in

        if elemType == null || lazy == null then

          null

        else

          {

            inherit elemType lazy;

          };

    in

    {

      elemType,

      lazy ? false,

    }:

    mkOptionType {

      name = typeName;

      name = if lazy then "lazyAttrsOf" else "attrsOf";

      description = (if lazy then "lazy attribute set" else "attribute set") + " of ${optionDescriptionPhrase (class: class == "noun" || class == "composite") elemType}";

      descriptionClass = "composite";

      check = isAttrs;

          # Important!: Add new function attributes here in case of future changes

          inherit elemType lazy;

        };

        binOp = lhs: rhs:

          let

            elemType = lhs.elemType.typeMerge rhs.elemType.functor;

            lazy =

              if lhs.lazy == rhs.lazy then

                lhs.lazy

              else

                null;

          in

          if elemType == null || lazy == null then

            null

          else

            {

              inherit elemType lazy;

            };

        inherit binOp;

      };

      nestedTypes.elemType = elemType;

    };