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LotsaValues.sol

pragma solidity ^0.5.0;

contract Configuration {
    uint256 public val1  = 1;
    uint256 public val2  = 2;
    uint256 public val3  = 3;
    uint256 public val4  = 4;
    uint256 public val5  = 5;
    uint256 public val6  = 6;
    uint256 public val7  = 7;
    uint256 public val8  = 8;
    uint256 public val9  = 9;
    uint256 public val10 = 10;
    uint256 public val11 = 11;
    uint256 public val12 = 12;
    uint256 public val13 = 13;
    uint256 public val14 = 14;
    uint256 public val15 = 15;
    uint256 public val16 = 16;
    uint256 public val17 = 17;
    uint256 public val18 = 18;
    uint256 public val19 = 19;
    uint256 public val20 = 20;
}

contract LotsaValuesConfig {

    uint256 public result;

    function initialize(Configuration _config) public {
        result =
          _config.val1() +
          _config.val2() +
          _config.val3() +
          _config.val4() + // Stack too deep occurs here.
          _config.val5() +
          _config.val6() +
          _config.val7() +
          _config.val8() +
          _config.val9() +
          _config.val10() +
          _config.val11() +
          _config.val12() +
          _config.val13() +
          _config.val14() +
          _config.val15() +
          _config.val16() +
          _config.val17() +
          _config.val18() +
          _config.val19() +
          _config.val20();
    }
}

contract LotsaValuesParams {

    uint256 public result;

    function initialize(
      uint256 _value1,
      uint256 _value2,
      uint256 _value3,
      uint256 _value4,
      uint256 _value5,
      uint256 _value6,
      uint256 _value7,
      uint256 _value8,
      uint256 _value9,
      uint256 _value10,
      uint256 _value11,
      uint256 _value12,
      uint256 _value13,
      uint256 _value14,
      uint256 _value15,
      uint256 _value16,
      uint256 _value17,
      uint256 _value18,
      uint256 _value19,
      uint256 _value20
    )
        public
    {
      result =
        _value1 +
        _value2 +
        _value3 +
        _value4 +
        _value5 +
        _value6 +
        _value7 +
        _value8 +
        _value9 +
        _value10 +
        _value11 +
        _value12 + // Stack too deep occurs here.
        _value13 +
        _value14 +
        _value15 +
        _value16 +
        _value17 +
        _value18 +
        _value19 +
        _value20;
    }
}