diff --git a/ClosedXML/Excel/AutoFilters/XLAutoFilter.cs b/ClosedXML/Excel/AutoFilters/XLAutoFilter.cs
index ec79a5c..6fb573e 100644
--- a/ClosedXML/Excel/AutoFilters/XLAutoFilter.cs
+++ b/ClosedXML/Excel/AutoFilters/XLAutoFilter.cs
@@ -71,8 +71,7 @@
             if (column < 1 || column > XLHelper.MaxColumnNumber)
                 throw new ArgumentOutOfRangeException(nameof(column), "Column " + column + " is outside the allowed column range.");
 
-            XLFilterColumn filterColumn;
-            if (!_columns.TryGetValue(column, out filterColumn))
+            if (!_columns.TryGetValue(column, out XLFilterColumn filterColumn))
             {
                 filterColumn = new XLFilterColumn(this, column);
                 _columns.Add(column, filterColumn);
diff --git a/ClosedXML/Excel/AutoFilters/XLFilterColumn.cs b/ClosedXML/Excel/AutoFilters/XLFilterColumn.cs
index dc4bceb..a6cd574 100644
--- a/ClosedXML/Excel/AutoFilters/XLFilterColumn.cs
+++ b/ClosedXML/Excel/AutoFilters/XLFilterColumn.cs
@@ -47,8 +47,7 @@
 
             _autoFilter.Enabled = true;
 
-            List<XLFilter> filterList;
-            if (_autoFilter.Filters.TryGetValue(_column, out filterList))
+            if (_autoFilter.Filters.TryGetValue(_column, out List<XLFilter> filterList))
                 filterList.Add(
                     new XLFilter
                     {
@@ -396,8 +395,7 @@
             }
             else
             {
-                List<XLFilter> filterList;
-                if (_autoFilter.Filters.TryGetValue(_column, out filterList))
+                if (_autoFilter.Filters.TryGetValue(_column, out List<XLFilter> filterList))
                     filterList.Add(new XLFilter
                     {
                         Value = value,
diff --git a/ClosedXML/Excel/Caching/XLRepositoryBase.cs b/ClosedXML/Excel/Caching/XLRepositoryBase.cs
index 5d2c5fe..85cc546 100644
--- a/ClosedXML/Excel/Caching/XLRepositoryBase.cs
+++ b/ClosedXML/Excel/Caching/XLRepositoryBase.cs
@@ -40,8 +40,7 @@
         /// <returns>True if entry exists and alive, false otherwise.</returns>
         public bool ContainsKey(Tkey key, out Tvalue value)
         {
-            WeakReference cachedReference;
-            if (_storage.TryGetValue(key, out cachedReference))
+            if (_storage.TryGetValue(key, out WeakReference cachedReference))
             {
                 value = cachedReference.Target as Tvalue;
                 return (value != null);
@@ -88,8 +87,7 @@
         /// </summary>
         public Tvalue GetOrCreate(Tkey key)
         {
-            WeakReference cachedReference;
-            if (_storage.TryGetValue(key, out cachedReference))
+            if (_storage.TryGetValue(key, out WeakReference cachedReference))
             {
                 var storedValue = cachedReference.Target as Tvalue;
                 if (storedValue != null)
@@ -98,11 +96,10 @@
                 }
                 else
                 {
-                    WeakReference _;
-                    _storage.TryRemove(key, out _);
+                    _storage.TryRemove(key, out WeakReference _);
                 }
             }
-            
+
             var value = _createNew(key);
             return Store(key, value);
         }
@@ -123,8 +120,7 @@
                     var val = pair.Value.Target as Tvalue;
                     if (val == null)
                     {
-                        WeakReference _;
-                        _storage.TryRemove(pair.Key, out _);
+                        _storage.TryRemove(pair.Key, out WeakReference _);
                     }
                     return val;
                 })
diff --git a/ClosedXML/Excel/CalcEngine/CalcEngine.cs b/ClosedXML/Excel/CalcEngine/CalcEngine.cs
index c1a1aa1..c68df40 100644
--- a/ClosedXML/Excel/CalcEngine/CalcEngine.cs
+++ b/ClosedXML/Excel/CalcEngine/CalcEngine.cs
@@ -264,7 +264,6 @@
             ["#NUM!"] = ErrorExpression.ExpressionErrorType.NumberInvalid
         };
 
-
         // build/get static token table
         private Dictionary<object, Token> GetSymbolTable()
         {
@@ -404,7 +403,6 @@
         {
             string id;
             Expression x = null;
-            FunctionDefinition fnDef = null;
 
             switch (_token.Type)
             {
@@ -420,7 +418,7 @@
                     id = (string)_token.Value;
 
                     // look for functions
-                    if (_fnTbl.TryGetValue(id, out fnDef))
+                    if (_fnTbl.TryGetValue(id, out FunctionDefinition fnDef))
                     {
                         var p = GetParameters();
                         var pCnt = p == null ? 0 : p.Count;
@@ -550,21 +548,19 @@
                     }
 
                     // look up single-char tokens on table
-                    Token tk;
-                    if (_tkTbl.TryGetValue(c, out tk))
+                    if (_tkTbl.TryGetValue(c, out Token tk))
                     {
                         // save token we found
                         _token = tk;
                         _ptr++;
 
                         // look for double-char tokens (special case)
-                        if (_ptr < _len && (c == '>' || c == '<'))
+                        if (_ptr < _len
+                            && (c == '>' || c == '<')
+                            && _tkTbl.TryGetValue(_expr.Substring(_ptr - 1, 2), out tk))
                         {
-                            if (_tkTbl.TryGetValue(_expr.Substring(_ptr - 1, 2), out tk))
-                            {
-                                _token = tk;
-                                _ptr++;
-                            }
+                            _token = tk;
+                            _ptr++;
                         }
 
                         // found token on the table
@@ -680,7 +676,7 @@
             }
 
             // parse #REF! (and other errors) in formula
-            if (c == '#' && ErrorMap.Any(pair => _len > _ptr+pair.Key.Length && _expr.Substring(_ptr, pair.Key.Length).Equals(pair.Key, StringComparison.OrdinalIgnoreCase)))
+            if (c == '#' && ErrorMap.Any(pair => _len > _ptr + pair.Key.Length && _expr.Substring(_ptr, pair.Key.Length).Equals(pair.Key, StringComparison.OrdinalIgnoreCase)))
             {
                 var errorPair = ErrorMap.Single(pair => _len > _ptr + pair.Key.Length && _expr.Substring(_ptr, pair.Key.Length).Equals(pair.Key, StringComparison.OrdinalIgnoreCase));
                 _ptr += errorPair.Key.Length;
diff --git a/ClosedXML/Excel/CalcEngine/CalcEngineHelpers.cs b/ClosedXML/Excel/CalcEngine/CalcEngineHelpers.cs
index 00d8a32..6a01456 100644
--- a/ClosedXML/Excel/CalcEngine/CalcEngineHelpers.cs
+++ b/ClosedXML/Excel/CalcEngine/CalcEngineHelpers.cs
@@ -36,8 +36,7 @@
             {
                 if (value is Double)
                     return (double)value == (double)criteria;
-                Double dValue;
-                return Double.TryParse(value.ToString(), out dValue) && dValue == (double)criteria;
+                return Double.TryParse(value.ToString(), out double dValue) && dValue == (double)criteria;
             }
 
             // convert criteria to string
@@ -61,17 +60,14 @@
                     // add quotes if necessary
                     var pattern = @"([\w\s]+)(\W+)(\w+)";
                     var m = Regex.Match(expression, pattern);
-                    if (m.Groups.Count == 4)
+                    if (m.Groups.Count == 4
+                        && (!double.TryParse(m.Groups[1].Value, out double d) ||
+                            !double.TryParse(m.Groups[3].Value, out d)))
                     {
-                        double d;
-                        if (!double.TryParse(m.Groups[1].Value, out d) ||
-                            !double.TryParse(m.Groups[3].Value, out d))
-                        {
-                            expression = string.Format("\"{0}\"{1}\"{2}\"",
-                                                       m.Groups[1].Value,
-                                                       m.Groups[2].Value,
-                                                       m.Groups[3].Value);
-                        }
+                        expression = string.Format("\"{0}\"{1}\"{2}\"",
+                                                   m.Groups[1].Value,
+                                                   m.Groups[2].Value,
+                                                   m.Groups[3].Value);
                     }
 
                     // evaluate
diff --git a/ClosedXML/Excel/CalcEngine/ExpressionCache.cs b/ClosedXML/Excel/CalcEngine/ExpressionCache.cs
index 57640a4..b688271 100644
--- a/ClosedXML/Excel/CalcEngine/ExpressionCache.cs
+++ b/ClosedXML/Excel/CalcEngine/ExpressionCache.cs
@@ -29,8 +29,7 @@
             get
             {
                 Expression x;
-                WeakReference wr;
-                if (_dct.TryGetValue(expression, out wr) && wr.IsAlive)
+                if (_dct.TryGetValue(expression, out WeakReference wr) && wr.IsAlive)
                 {
                     x = wr.Target as Expression;
                 }
diff --git a/ClosedXML/Excel/CalcEngine/Functions/Information.cs b/ClosedXML/Excel/CalcEngine/Functions/Information.cs
index 6b19dfb..be8b7bc 100644
--- a/ClosedXML/Excel/CalcEngine/Functions/Information.cs
+++ b/ClosedXML/Excel/CalcEngine/Functions/Information.cs
@@ -130,8 +130,7 @@
                 try
                 {
                     var stringValue = (string) v;
-                    double dv;
-                    return double.TryParse(stringValue.TrimEnd('%', ' '), NumberStyles.Any, null, out dv);
+                    return double.TryParse(stringValue.TrimEnd('%', ' '), NumberStyles.Any, null, out double dv);
                 }
                 catch (Exception)
                 {
diff --git a/ClosedXML/Excel/CalcEngine/Functions/MathTrig.cs b/ClosedXML/Excel/CalcEngine/Functions/MathTrig.cs
index 4eb642e..db1306d 100644
--- a/ClosedXML/Excel/CalcEngine/Functions/MathTrig.cs
+++ b/ClosedXML/Excel/CalcEngine/Functions/MathTrig.cs
@@ -829,11 +829,9 @@
 
         private static object Roman(List<Expression> p)
         {
-            Int32 intTemp;
-            Boolean boolTemp;
             if (p.Count == 1
-                || (Boolean.TryParse(p[1]._token.Value.ToString(), out boolTemp) && boolTemp)
-                || (Int32.TryParse(p[1]._token.Value.ToString(), out intTemp) && intTemp == 1))
+                || (Boolean.TryParse(p[1]._token.Value.ToString(), out bool boolTemp) && boolTemp)
+                || (Int32.TryParse(p[1]._token.Value.ToString(), out int intTemp) && intTemp == 1))
                 return XLMath.ToRoman((int)p[0]);
 
             throw new ArgumentException("Can only support classic roman types.");
@@ -880,8 +878,7 @@
 
         private static object Sec(List<Expression> p)
         {
-            double number;
-            if (double.TryParse(p[0], out number))
+            if (double.TryParse(p[0], out double number))
                 return 1.0 / Math.Cos(number);
             else
                 throw new CellValueException();
diff --git a/ClosedXML/Excel/CalcEngine/Functions/Tally.cs b/ClosedXML/Excel/CalcEngine/Functions/Tally.cs
index cd6b4d5..5f609cf 100644
--- a/ClosedXML/Excel/CalcEngine/Functions/Tally.cs
+++ b/ClosedXML/Excel/CalcEngine/Functions/Tally.cs
@@ -87,18 +87,17 @@
         {
             foreach (var value in _list)
             {
-                double tmp;
                 var vEnumerable = value as IEnumerable;
                 if (vEnumerable == null || vEnumerable is string)
                 {
-                    if (TryParseToDouble(value, out tmp))
+                    if (TryParseToDouble(value, out double tmp))
                         yield return tmp;
                 }
                 else
                 {
                     foreach (var v in vEnumerable)
                     {
-                        if (TryParseToDouble(v, out tmp))
+                        if (TryParseToDouble(v, out double tmp))
                             yield return tmp;
                     }
                 }
diff --git a/ClosedXML/Excel/CalcEngine/XLCalcEngine.cs b/ClosedXML/Excel/CalcEngine/XLCalcEngine.cs
index da2f83b..4c161f9 100644
--- a/ClosedXML/Excel/CalcEngine/XLCalcEngine.cs
+++ b/ClosedXML/Excel/CalcEngine/XLCalcEngine.cs
@@ -44,8 +44,7 @@
                     throw new ArgumentOutOfRangeException(referencedSheetNames.Last(), "Cross worksheet references may references no more than 1 other worksheet");
                 else
                 {
-                    IXLWorksheet worksheet;
-                    if (!_wb.TryGetWorksheet(referencedSheetNames.Single(), out worksheet))
+                    if (!_wb.TryGetWorksheet(referencedSheetNames.Single(), out IXLWorksheet worksheet))
                         throw new ArgumentOutOfRangeException(referencedSheetNames.Single(), "The required worksheet cannot be found");
 
                     identifier = identifier.ToLower().Replace(string.Format("{0}!", worksheet.Name.ToLower()), "");
diff --git a/ClosedXML/Excel/Cells/XLCell.cs b/ClosedXML/Excel/Cells/XLCell.cs
index dab1b88..e331477 100644
--- a/ClosedXML/Excel/Cells/XLCell.cs
+++ b/ClosedXML/Excel/Cells/XLCell.cs
@@ -336,8 +336,7 @@
                 return (cValue != "0").ToExcelFormat(format);
             else if (_dataType == XLDataType.TimeSpan || _dataType == XLDataType.DateTime || IsDateFormat())
             {
-                double dTest;
-                if (Double.TryParse(cValue, XLHelper.NumberStyle, XLHelper.ParseCulture, out dTest)
+                if (Double.TryParse(cValue, XLHelper.NumberStyle, XLHelper.ParseCulture, out Double dTest)
                     && dTest.IsValidOADateNumber())
                 {
                     return DateTime.FromOADate(dTest).ToExcelFormat(format);
@@ -347,8 +346,7 @@
             }
             else if (_dataType == XLDataType.Number)
             {
-                double dTest;
-                if (Double.TryParse(cValue, XLHelper.NumberStyle, XLHelper.ParseCulture, out dTest))
+                if (Double.TryParse(cValue, XLHelper.NumberStyle, XLHelper.ParseCulture, out Double dTest))
                 {
                     return dTest.ToExcelFormat(format);
                 }
@@ -431,27 +429,21 @@
                 if (_dataType == XLDataType.Boolean)
                     return cellValue != "0";
 
-                if (_dataType == XLDataType.DateTime)
-                {
-                    Double d;
-                    if (Double.TryParse(cellValue, XLHelper.NumberStyle, XLHelper.ParseCulture, out d)
-                        && d.IsValidOADateNumber())
-                        return DateTime.FromOADate(d);
-                }
+                if (_dataType == XLDataType.DateTime
+                    && Double.TryParse(cellValue, XLHelper.NumberStyle, XLHelper.ParseCulture, out Double d)
+                    && d.IsValidOADateNumber())
 
-                if (_dataType == XLDataType.Number)
-                {
-                    Double d;
-                    if (double.TryParse(cellValue, XLHelper.NumberStyle, XLHelper.ParseCulture, out d))
-                        return d;
-                }
+                    return DateTime.FromOADate(d);
 
-                if (_dataType == XLDataType.TimeSpan)
-                {
-                    TimeSpan t;
-                    if (TimeSpan.TryParse(cellValue, out t))
-                        return t;
-                }
+                if (_dataType == XLDataType.Number
+                    && double.TryParse(cellValue, XLHelper.NumberStyle, XLHelper.ParseCulture, out Double n))
+
+                    return n;
+
+                if (_dataType == XLDataType.TimeSpan
+                    && TimeSpan.TryParse(cellValue, out TimeSpan t))
+
+                    return t;
 
                 return cellValue;
             }
@@ -933,19 +925,16 @@
                 {
                     if (value == XLDataType.Boolean)
                     {
-                        bool bTest;
-                        if (Boolean.TryParse(_cellValue, out bTest))
+                        if (Boolean.TryParse(_cellValue, out Boolean bTest))
                             _cellValue = bTest ? "1" : "0";
                         else
                             _cellValue = _cellValue == "0" || String.IsNullOrEmpty(_cellValue) ? "0" : "1";
                     }
                     else if (value == XLDataType.DateTime)
                     {
-                        DateTime dtTest;
-                        double dblTest;
-                        if (DateTime.TryParse(_cellValue, out dtTest))
+                        if (DateTime.TryParse(_cellValue, out DateTime dtTest))
                             _cellValue = dtTest.ToOADate().ToInvariantString();
-                        else if (Double.TryParse(_cellValue, XLHelper.NumberStyle, XLHelper.ParseCulture, out dblTest))
+                        else if (Double.TryParse(_cellValue, XLHelper.NumberStyle, XLHelper.ParseCulture, out Double dblTest))
                             _cellValue = dblTest.ToInvariantString();
                         else
                         {
@@ -960,8 +949,7 @@
                     }
                     else if (value == XLDataType.TimeSpan)
                     {
-                        TimeSpan tsTest;
-                        if (TimeSpan.TryParse(_cellValue, out tsTest))
+                        if (TimeSpan.TryParse(_cellValue, out TimeSpan tsTest))
                         {
                             _cellValue = tsTest.ToString();
                             var style = GetStyleForRead();
@@ -986,7 +974,6 @@
                     else if (value == XLDataType.Number)
                     {
                         var v = _cellValue;
-                        double dTest;
                         double factor = 1.0;
                         if (v.EndsWith("%"))
                         {
@@ -994,7 +981,7 @@
                             factor = 1 / 100.0;
                         }
 
-                        if (Double.TryParse(v, XLHelper.NumberStyle, CultureInfo.InvariantCulture, out dTest))
+                        if (Double.TryParse(v, XLHelper.NumberStyle, CultureInfo.InvariantCulture, out Double dTest))
                             _cellValue = (dTest * factor).ToInvariantString();
                         else
                         {
@@ -1264,12 +1251,10 @@
 
                 if (StyleValue.Equals(Worksheet.StyleValue))
                 {
-                    XLRow row;
-                    if (Worksheet.Internals.RowsCollection.TryGetValue(_rowNumber, out row) && !row.StyleValue.Equals(Worksheet.StyleValue))
+                    if (Worksheet.Internals.RowsCollection.TryGetValue(_rowNumber, out XLRow row) && !row.StyleValue.Equals(Worksheet.StyleValue))
                         return false;
 
-                    XLColumn column;
-                    if (Worksheet.Internals.ColumnsCollection.TryGetValue(_columnNumber, out column) && !column.StyleValue.Equals(Worksheet.StyleValue))
+                    if (Worksheet.Internals.ColumnsCollection.TryGetValue(_columnNumber, out XLColumn column) && !column.StyleValue.Equals(Worksheet.StyleValue))
                         return false;
                 }
             }
@@ -1412,8 +1397,7 @@
                 return true;
             }
 
-            bool b;
-            if (TryGetTimeSpanValue(out value, currValue, out b)) return b;
+            if (TryGetTimeSpanValue(out value, currValue, out Boolean b)) return b;
 
             if (TryGetRichStringValue(out value)) return true;
 
@@ -1533,8 +1517,7 @@
         {
             if (typeof(T) == typeof(Boolean))
             {
-                Boolean tmp;
-                if (Boolean.TryParse(currValue.ToString(), out tmp))
+                if (Boolean.TryParse(currValue.ToString(), out Boolean tmp))
                 {
                     value = (T)Convert.ChangeType(tmp, typeof(T));
                     {
@@ -1550,8 +1533,7 @@
 
         private static Boolean TryGetBasicValue<T, U>(out T value, String currValue, Func<U> func)
         {
-            U tmp;
-            if (func(currValue, out tmp))
+            if (func(currValue, out U tmp))
             {
                 value = (T)Convert.ChangeType(tmp, typeof(T));
                 {
@@ -1916,10 +1898,6 @@
                 _dataType = XLDataType.Text;
             else
             {
-                double dTest;
-                DateTime dtTest;
-                bool bTest;
-                TimeSpan tsTest;
                 var style = GetStyleForRead();
                 if (style.NumberFormat.Format == "@")
                 {
@@ -1934,7 +1912,8 @@
                     if (val.Contains(Environment.NewLine) && !style.Alignment.WrapText)
                         Style.Alignment.WrapText = true;
                 }
-                else if (value is TimeSpan || (!Double.TryParse(val, XLHelper.NumberStyle, XLHelper.ParseCulture, out dTest) && TimeSpan.TryParse(val, out tsTest)))
+                // TODO: sort out the double TimeSpan parsing
+                else if (value is TimeSpan || (!Double.TryParse(val, XLHelper.NumberStyle, XLHelper.ParseCulture, out Double d1) && TimeSpan.TryParse(val, out TimeSpan tsTest)))
                 {
                     if (!(value is TimeSpan) && TimeSpan.TryParse(val, out tsTest))
                         val = tsTest.ToString();
@@ -1943,9 +1922,9 @@
                     if (style.NumberFormat.Format == String.Empty && style.NumberFormat.NumberFormatId == 0)
                         Style.NumberFormat.NumberFormatId = 46;
                 }
-                else if (val.Trim() != "NaN" && Double.TryParse(val, XLHelper.NumberStyle, XLHelper.ParseCulture, out dTest))
+                else if (val.Trim() != "NaN" && Double.TryParse(val, XLHelper.NumberStyle, XLHelper.ParseCulture, out Double d2))
                     _dataType = XLDataType.Number;
-                else if (DateTime.TryParse(val, out dtTest) && dtTest >= BaseDate)
+                else if (DateTime.TryParse(val, out DateTime dtTest) && dtTest >= BaseDate)
                 {
                     _dataType = XLDataType.DateTime;
 
@@ -1963,7 +1942,7 @@
                         }
                     }
                 }
-                else if (Boolean.TryParse(val, out bTest))
+                else if (Boolean.TryParse(val, out Boolean bTest))
                 {
                     _dataType = XLDataType.Boolean;
                     val = bTest ? "1" : "0";
@@ -2127,8 +2106,7 @@
                 var parts = a1Address.Split(':');
                 var p1 = parts[0];
                 var p2 = parts[1];
-                int row1;
-                if (Int32.TryParse(p1.Replace("$", string.Empty), out row1))
+                if (Int32.TryParse(p1.Replace("$", string.Empty), out Int32 row1))
                 {
                     var row2 = Int32.Parse(p2.Replace("$", string.Empty));
                     var leftPart = GetR1C1Row(row1, p1.Contains('$'), rowsToShift);
diff --git a/ClosedXML/Excel/Cells/XLCellsCollection.cs b/ClosedXML/Excel/Cells/XLCellsCollection.cs
index 2a70742..2cd1490 100644
--- a/ClosedXML/Excel/Cells/XLCellsCollection.cs
+++ b/ClosedXML/Excel/Cells/XLCellsCollection.cs
@@ -6,7 +6,6 @@
 {
     internal class XLCellsCollection
     {
-
         private readonly Dictionary<int, Dictionary<int, XLCell>> rowsCollection = new Dictionary<int, Dictionary<int, XLCell>>();
         public readonly Dictionary<Int32, Int32> ColumnsUsed = new Dictionary<int, int>();
         public readonly Dictionary<Int32, HashSet<Int32>> deleted = new Dictionary<int, HashSet<int>>();
@@ -27,7 +26,6 @@
 
         public Int32 Count { get; private set; }
 
-
         public void Add(XLSheetPoint sheetPoint, XLCell cell)
         {
             Add(sheetPoint.Row, sheetPoint.Column, cell);
@@ -40,8 +38,7 @@
             IncrementUsage(RowsUsed, row);
             IncrementUsage(ColumnsUsed, column);
 
-            Dictionary<int, XLCell> columnsCollection;
-            if (!rowsCollection.TryGetValue(row, out columnsCollection))
+            if (!rowsCollection.TryGetValue(row, out Dictionary<int, XLCell> columnsCollection))
             {
                 columnsCollection = new Dictionary<int, XLCell>();
                 rowsCollection.Add(row, columnsCollection);
@@ -50,8 +47,7 @@
             if (row > MaxRowUsed) MaxRowUsed = row;
             if (column > MaxColumnUsed) MaxColumnUsed = column;
 
-            HashSet<Int32> delHash;
-            if (deleted.TryGetValue(row, out delHash))
+            if (deleted.TryGetValue(row, out HashSet<int> delHash))
                 delHash.Remove(column);
         }
 
@@ -65,8 +61,7 @@
 
         private static void DecrementUsage(Dictionary<int, int> dictionary, Int32 key)
         {
-            Int32 count;
-            if (!dictionary.TryGetValue(key, out count)) return;
+            if (!dictionary.TryGetValue(key, out Int32 count)) return;
 
             if (count > 0)
                 dictionary[key]--;
@@ -96,8 +91,7 @@
             DecrementUsage(RowsUsed, row);
             DecrementUsage(ColumnsUsed, row);
 
-            HashSet<Int32> delHash;
-            if (deleted.TryGetValue(row, out delHash))
+            if (deleted.TryGetValue(row, out HashSet<Int32> delHash))
             {
                 if (!delHash.Contains(column))
                     delHash.Add(column);
@@ -109,8 +103,7 @@
                 deleted.Add(row, delHash);
             }
 
-            Dictionary<int, XLCell> columnsCollection;
-            if (rowsCollection.TryGetValue(row, out columnsCollection))
+            if (rowsCollection.TryGetValue(row, out Dictionary<Int32, XLCell> columnsCollection))
             {
                 columnsCollection.Remove(column);
                 if (columnsCollection.Count == 0)
@@ -118,8 +111,6 @@
                     rowsCollection.Remove(row);
                 }
             }
-
-
         }
 
         internal IEnumerable<XLCell> GetCells(Int32 rowStart, Int32 columnStart,
@@ -130,13 +121,11 @@
             int finalColumn = columnEnd > MaxColumnUsed ? MaxColumnUsed : columnEnd;
             for (int ro = rowStart; ro <= finalRow; ro++)
             {
-                Dictionary<int, XLCell> columnsCollection;
-                if (rowsCollection.TryGetValue(ro, out columnsCollection))
+                if (rowsCollection.TryGetValue(ro, out Dictionary<Int32, XLCell> columnsCollection))
                 {
                     for (int co = columnStart; co <= finalColumn; co++)
                     {
-                        XLCell cell;
-                        if (columnsCollection.TryGetValue(co, out cell)
+                        if (columnsCollection.TryGetValue(co, out XLCell cell)
                             && (predicate == null || predicate(cell)))
                             yield return cell;
                     }
@@ -152,20 +141,18 @@
             int finalColumn = columnEnd > MaxColumnUsed ? MaxColumnUsed : columnEnd;
             for (int ro = rowStart; ro <= finalRow; ro++)
             {
-                Dictionary<int, XLCell> columnsCollection;
-                if (rowsCollection.TryGetValue(ro, out columnsCollection))
+                if (rowsCollection.TryGetValue(ro, out Dictionary<Int32, XLCell> columnsCollection))
                 {
                     for (int co = columnStart; co <= finalColumn; co++)
                     {
-                        XLCell cell;
-                        if (columnsCollection.TryGetValue(co, out cell)
-                        && !cell.IsEmpty(includeFormats)
-                        && (predicate == null || predicate(cell)))
+                        if (columnsCollection.TryGetValue(co, out XLCell cell)
+                            && !cell.IsEmpty(includeFormats)
+                            && (predicate == null || predicate(cell)))
+
                             yield return cell;
                     }
                 }
             }
-
         }
 
         public XLSheetPoint FirstPointUsed(Int32 rowStart, Int32 columnStart,
@@ -205,15 +192,14 @@
             int finalColumn = columnEnd > MaxColumnUsed ? MaxColumnUsed : columnEnd;
             for (int ro = rowStart; ro <= finalRow; ro++)
             {
-                Dictionary<int, XLCell> columnsCollection;
-                if (rowsCollection.TryGetValue(ro, out columnsCollection))
+                if (rowsCollection.TryGetValue(ro, out Dictionary<Int32, XLCell> columnsCollection))
                 {
                     for (int co = columnStart; co <= finalColumn; co++)
                     {
-                        XLCell cell;
-                        if (columnsCollection.TryGetValue(co, out cell)
-                        && !cell.IsEmpty(includeFormats)
-                        && (predicate == null || predicate(cell)))
+                        if (columnsCollection.TryGetValue(co, out XLCell cell)
+                            && !cell.IsEmpty(includeFormats)
+                            && (predicate == null || predicate(cell)))
+
                             return ro;
                     }
                 }
@@ -228,15 +214,14 @@
             int finalColumn = columnEnd > MaxColumnUsed ? MaxColumnUsed : columnEnd;
             for (int ro = rowStart; ro <= finalRow; ro++)
             {
-                Dictionary<int, XLCell> columnsCollection;
-                if (rowsCollection.TryGetValue(ro, out columnsCollection))
+                if (rowsCollection.TryGetValue(ro, out Dictionary<Int32, XLCell> columnsCollection))
                 {
                     for (int co = columnStart; co <= finalColumn; co++)
                     {
-                        XLCell cell;
-                        if (columnsCollection.TryGetValue(co, out cell)
-                        && !cell.IsEmpty(includeFormats)
-                        && (predicate == null || predicate(cell)))
+                        if (columnsCollection.TryGetValue(co, out XLCell cell)
+                            && !cell.IsEmpty(includeFormats)
+                            && (predicate == null || predicate(cell)))
+
                             return co;
                     }
                 }
@@ -245,22 +230,20 @@
             return 0;
         }
 
-
         public int LastRowUsed(int rowStart, int columnStart, int rowEnd, int columnEnd, Boolean includeFormats, Func<IXLCell, Boolean> predicate = null)
         {
             int finalRow = rowEnd > MaxRowUsed ? MaxRowUsed : rowEnd;
             int finalColumn = columnEnd > MaxColumnUsed ? MaxColumnUsed : columnEnd;
             for (int ro = finalRow; ro >= rowStart; ro--)
             {
-                Dictionary<int, XLCell> columnsCollection;
-                if (rowsCollection.TryGetValue(ro, out columnsCollection))
+                if (rowsCollection.TryGetValue(ro, out Dictionary<Int32, XLCell> columnsCollection))
                 {
                     for (int co = finalColumn; co >= columnStart; co--)
                     {
-                        XLCell cell;
-                        if (columnsCollection.TryGetValue(co, out cell)
-                         && !cell.IsEmpty(includeFormats)
-                        && (predicate == null || predicate(cell)))
+                        if (columnsCollection.TryGetValue(co, out XLCell cell)
+                            && !cell.IsEmpty(includeFormats)
+                            && (predicate == null || predicate(cell)))
+
                             return ro;
                     }
                 }
@@ -275,15 +258,14 @@
             int finalColumn = columnEnd > MaxColumnUsed ? MaxColumnUsed : columnEnd;
             for (int ro = finalRow; ro >= rowStart; ro--)
             {
-                Dictionary<int, XLCell> columnsCollection;
-                if (rowsCollection.TryGetValue(ro, out columnsCollection))
+                if (rowsCollection.TryGetValue(ro, out Dictionary<int, XLCell> columnsCollection))
                 {
                     for (int co = finalColumn; co >= columnStart && co > maxCo; co--)
                     {
-                        XLCell cell;
-                        if (columnsCollection.TryGetValue(co, out cell)
-                         && !cell.IsEmpty(includeFormats)
-                        && (predicate == null || predicate(cell)))
+                        if (columnsCollection.TryGetValue(co, out XLCell cell)
+                            && !cell.IsEmpty(includeFormats)
+                            && (predicate == null || predicate(cell)))
+
                             maxCo = co;
                     }
                 }
@@ -298,8 +280,7 @@
             int finalColumn = columnEnd > MaxColumnUsed ? MaxColumnUsed : columnEnd;
             for (int ro = rowStart; ro <= finalRow; ro++)
             {
-                Dictionary<int, XLCell> columnsCollection;
-                if (rowsCollection.TryGetValue(ro, out columnsCollection))
+                if (rowsCollection.TryGetValue(ro, out Dictionary<int, XLCell> columnsCollection))
                 {
                     for (int co = columnStart; co <= finalColumn; co++)
                     {
@@ -317,8 +298,7 @@
             int finalColumn = columnEnd > MaxColumnUsed ? MaxColumnUsed : columnEnd;
             for (int ro = rowStart; ro <= finalRow; ro++)
             {
-                Dictionary<int, XLCell> columnsCollection;
-                if (rowsCollection.TryGetValue(ro, out columnsCollection))
+                if (rowsCollection.TryGetValue(ro, out Dictionary<Int32, XLCell> columnsCollection))
                 {
                     for (int co = columnStart; co <= finalColumn; co++)
                     {
@@ -333,11 +313,10 @@
         {
             if (row > MaxRowUsed || column > MaxColumnUsed)
                 return null;
-            Dictionary<int, XLCell> columnsCollection;
-            if (rowsCollection.TryGetValue(row, out columnsCollection))
+
+            if (rowsCollection.TryGetValue(row, out Dictionary<Int32, XLCell> columnsCollection))
             {
-                XLCell cell;
-                return columnsCollection.TryGetValue(column, out cell) ? cell : null;
+                return columnsCollection.TryGetValue(column, out XLCell cell) ? cell : null;
             }
             return null;
         }
@@ -390,37 +369,32 @@
         {
             for (int ro = 1; ro <= MaxRowUsed; ro++)
             {
-                Dictionary<int, XLCell> columnsCollection;
-                if (rowsCollection.TryGetValue(ro, out columnsCollection))
+                if (rowsCollection.TryGetValue(ro, out Dictionary<Int32, XLCell> columnsCollection))
                 {
                     for (int co = 1; co <= MaxColumnUsed; co++)
                     {
-                        XLCell cell;
-                        if (columnsCollection.TryGetValue(co, out cell)
+                        if (columnsCollection.TryGetValue(co, out XLCell cell)
                             && (predicate == null || predicate(cell)))
                             yield return cell;
                     }
                 }
             }
-
         }
 
         public Boolean Contains(Int32 row, Int32 column)
         {
-            Dictionary<int, XLCell> columnsCollection;
-            return rowsCollection.TryGetValue(row, out columnsCollection) && columnsCollection.ContainsKey(column);
+            return rowsCollection.TryGetValue(row, out Dictionary<Int32, XLCell> columnsCollection)
+                && columnsCollection.ContainsKey(column);
         }
 
         public Int32 MinRowInColumn(Int32 column)
         {
             for (int row = 1; row <= MaxRowUsed; row++)
             {
-                Dictionary<int, XLCell> columnsCollection;
-                if (rowsCollection.TryGetValue(row, out columnsCollection))
-                {
-                    if (columnsCollection.ContainsKey(column))
-                        return row;
-                }
+                if (rowsCollection.TryGetValue(row, out Dictionary<Int32, XLCell> columnsCollection)
+                    && columnsCollection.ContainsKey(column))
+
+                    return row;
             }
 
             return 0;
@@ -430,12 +404,10 @@
         {
             for (int row = MaxRowUsed; row >= 1; row--)
             {
-                Dictionary<int, XLCell> columnsCollection;
-                if (rowsCollection.TryGetValue(row, out columnsCollection))
-                {
-                    if (columnsCollection.ContainsKey(column))
-                        return row;
-                }
+                if (rowsCollection.TryGetValue(row, out Dictionary<Int32, XLCell> columnsCollection)
+                    && columnsCollection.ContainsKey(column))
+
+                    return row;
             }
 
             return 0;
@@ -443,24 +415,20 @@
 
         public Int32 MinColumnInRow(Int32 row)
         {
-            Dictionary<int, XLCell> columnsCollection;
-            if (rowsCollection.TryGetValue(row, out columnsCollection))
-            {
-                if (columnsCollection.Count > 0)
-                    return columnsCollection.Keys.Min();
-            }
+            if (rowsCollection.TryGetValue(row, out Dictionary<Int32, XLCell> columnsCollection)
+                && columnsCollection.Any())
+
+                return columnsCollection.Keys.Min();
 
             return 0;
         }
 
         public Int32 MaxColumnInRow(Int32 row)
         {
-            Dictionary<int, XLCell> columnsCollection;
-            if (rowsCollection.TryGetValue(row, out columnsCollection))
-            {
-                if (columnsCollection.Count > 0)
-                    return columnsCollection.Keys.Max();
-            }
+            if (rowsCollection.TryGetValue(row, out Dictionary<Int32, XLCell> columnsCollection)
+                && columnsCollection.Any())
+
+                return columnsCollection.Keys.Max();
 
             return 0;
         }
diff --git a/ClosedXML/Excel/ConditionalFormats/Save/XLCFCellIsConverter.cs b/ClosedXML/Excel/ConditionalFormats/Save/XLCFCellIsConverter.cs
index 2a3bf8e..9c02c83 100644
--- a/ClosedXML/Excel/ConditionalFormats/Save/XLCFCellIsConverter.cs
+++ b/ClosedXML/Excel/ConditionalFormats/Save/XLCFCellIsConverter.cs
@@ -31,8 +31,7 @@
         private String GetQuoted(XLFormula formula)
         {
             String value = formula.Value;
-            Double num;
-            if ((!Double.TryParse(value, out num) && !formula.IsFormula) && value[0] != '\"' && !value.EndsWith("\""))
+            if ((!Double.TryParse(value, out double num) && !formula.IsFormula) && value[0] != '\"' && !value.EndsWith("\""))
                 return String.Format("\"{0}\"", value.Replace("\"", "\"\""));
 
             return value;
diff --git a/ClosedXML/Excel/CustomProperties/XLCustomProperty.cs b/ClosedXML/Excel/CustomProperties/XLCustomProperty.cs
index bd5f5c6..d814355 100644
--- a/ClosedXML/Excel/CustomProperties/XLCustomProperty.cs
+++ b/ClosedXML/Excel/CustomProperties/XLCustomProperty.cs
@@ -33,14 +33,13 @@
         {
             get
             {
-                Double dTest;
                 if (Value is DateTime)
                     return XLCustomPropertyType.Date;
                 
                 if (Value is Boolean)
                     return XLCustomPropertyType.Boolean;
                 
-                if (Double.TryParse(Value.ToString(), out dTest))
+                if (Double.TryParse(Value.ToString(), out Double dTest))
                     return XLCustomPropertyType.Number;
                 
                 return XLCustomPropertyType.Text;
@@ -56,4 +55,4 @@
 
         #endregion
     }
-}
\ No newline at end of file
+}
diff --git a/ClosedXML/Excel/Drawings/XLPictures.cs b/ClosedXML/Excel/Drawings/XLPictures.cs
index 705ccb1..3cf1007 100644
--- a/ClosedXML/Excel/Drawings/XLPictures.cs
+++ b/ClosedXML/Excel/Drawings/XLPictures.cs
@@ -126,9 +126,7 @@
 
         public IXLPicture Picture(string pictureName)
         {
-            IXLPicture p;
-
-            if (TryGetPicture(pictureName, out p))
+            if (TryGetPicture(pictureName, out IXLPicture p))
                 return p;
 
             throw new ArgumentException($"There isn't a picture named '{pictureName}'.");
diff --git a/ClosedXML/Excel/Hyperlinks/XLHyperlink_Internal.cs b/ClosedXML/Excel/Hyperlinks/XLHyperlink_Internal.cs
index caf81d2..3705568 100644
--- a/ClosedXML/Excel/Hyperlinks/XLHyperlink_Internal.cs
+++ b/ClosedXML/Excel/Hyperlinks/XLHyperlink_Internal.cs
@@ -27,8 +27,7 @@
             }
             else
             {
-                Uri uri;
-                if(Uri.TryCreate(address, UriKind.Absolute, out uri))
+                if (Uri.TryCreate(address, UriKind.Absolute, out Uri uri))
                 {
                     _externalAddress = uri;
                     IsExternal = true;
diff --git a/ClosedXML/Excel/NamedRanges/XLNamedRanges.cs b/ClosedXML/Excel/NamedRanges/XLNamedRanges.cs
index f3f7304..30d6be8 100644
--- a/ClosedXML/Excel/NamedRanges/XLNamedRanges.cs
+++ b/ClosedXML/Excel/NamedRanges/XLNamedRanges.cs
@@ -25,8 +25,7 @@
 
         public IXLNamedRange NamedRange(String rangeName)
         {
-            IXLNamedRange range;
-            if (_namedRanges.TryGetValue(rangeName, out range))
+            if (_namedRanges.TryGetValue(rangeName, out IXLNamedRange range))
                 return range;
 
             return null;
diff --git a/ClosedXML/Excel/PageSetup/XLPageSetup.cs b/ClosedXML/Excel/PageSetup/XLPageSetup.cs
index 7e03392..f241e90 100644
--- a/ClosedXML/Excel/PageSetup/XLPageSetup.cs
+++ b/ClosedXML/Excel/PageSetup/XLPageSetup.cs
@@ -83,8 +83,7 @@
         public void SetColumnsToRepeatAtLeft(String range)
         {
             var arrRange = range.Replace("$", "").Split(':');
-            Int32 iTest;
-            if (Int32.TryParse(arrRange[0], out iTest))
+            if (Int32.TryParse(arrRange[0], out int iTest))
                 SetColumnsToRepeatAtLeft(Int32.Parse(arrRange[0]), Int32.Parse(arrRange[1]));
             else
                 SetColumnsToRepeatAtLeft(arrRange[0], arrRange[1]);
diff --git a/ClosedXML/Excel/Ranges/XLRange.cs b/ClosedXML/Excel/Ranges/XLRange.cs
index fbee6dd..8e29344 100644
--- a/ClosedXML/Excel/Ranges/XLRange.cs
+++ b/ClosedXML/Excel/Ranges/XLRange.cs
@@ -93,8 +93,7 @@
                     lastColumn = tPair;
                 }
 
-                Int32 tmp;
-                if (Int32.TryParse(firstColumn, out tmp))
+                if (Int32.TryParse(firstColumn, out Int32 tmp))
                 {
                     foreach (IXLRangeColumn col in Columns(Int32.Parse(firstColumn), Int32.Parse(lastColumn)))
                         retVal.Add(col);
diff --git a/ClosedXML/Excel/Ranges/XLRangeBase.cs b/ClosedXML/Excel/Ranges/XLRangeBase.cs
index 0e78b5a..313d82a 100644
--- a/ClosedXML/Excel/Ranges/XLRangeBase.cs
+++ b/ClosedXML/Excel/Ranges/XLRangeBase.cs
@@ -807,12 +807,10 @@
 
             if (styleValue == Worksheet.StyleValue)
             {
-                XLRow row;
-                XLColumn column;
-                if (Worksheet.Internals.RowsCollection.TryGetValue(absRow, out row)
+                if (Worksheet.Internals.RowsCollection.TryGetValue(absRow, out XLRow row)
                     && row.StyleValue != Worksheet.StyleValue)
                     styleValue = row.StyleValue;
-                else if (Worksheet.Internals.ColumnsCollection.TryGetValue(absColumn, out column)
+                else if (Worksheet.Internals.ColumnsCollection.TryGetValue(absColumn, out XLColumn column)
                     && column.StyleValue != Worksheet.StyleValue)
                     styleValue = column.StyleValue;
             }
@@ -954,16 +952,14 @@
 
         protected String FixColumnAddress(String address)
         {
-            Int32 test;
-            if (Int32.TryParse(address, out test))
+            if (Int32.TryParse(address, out Int32 test))
                 return "A" + address;
             return address;
         }
 
         protected String FixRowAddress(String address)
         {
-            Int32 test;
-            if (Int32.TryParse(address, out test))
+            if (Int32.TryParse(address, out Int32 test))
                 return XLHelper.GetColumnLetterFromNumber(test) + "1";
             return address;
         }
@@ -1767,8 +1763,7 @@
                     order = sortOrder == XLSortOrder.Ascending ? "ASC" : "DESC";
                 }
 
-                Int32 co;
-                if (!Int32.TryParse(coString, out co))
+                if (!Int32.TryParse(coString, out Int32 co))
                     co = XLHelper.GetColumnNumberFromLetter(coString);
 
                 SortColumns.Add(co, String.Compare(order, "ASC", true) == 0 ? XLSortOrder.Ascending : XLSortOrder.Descending, ignoreBlanks, matchCase);
diff --git a/ClosedXML/Excel/Tables/XLTable.cs b/ClosedXML/Excel/Tables/XLTable.cs
index 6eb0a9e..6df8a1a 100644
--- a/ClosedXML/Excel/Tables/XLTable.cs
+++ b/ClosedXML/Excel/Tables/XLTable.cs
@@ -534,8 +534,7 @@
                     order = sortOrder == XLSortOrder.Ascending ? "ASC" : "DESC";
                 }
 
-                Int32 co;
-                if (!Int32.TryParse(coString, out co))
+                if (!Int32.TryParse(coString, out Int32 co))
                     co = Field(coString).Index + 1;
 
                 if (toSortBy.Length > 0)
diff --git a/ClosedXML/Excel/XLWorkbook.cs b/ClosedXML/Excel/XLWorkbook.cs
index c9716be..4d5e1de 100644
--- a/ClosedXML/Excel/XLWorkbook.cs
+++ b/ClosedXML/Excel/XLWorkbook.cs
@@ -317,8 +317,7 @@
                 var first = split[0];
                 var wsName = first.StartsWith("'") ? first.Substring(1, first.Length - 2) : first;
                 var name = split[1];
-                IXLWorksheet ws;
-                if (TryGetWorksheet(wsName, out ws))
+                if (TryGetWorksheet(wsName, out IXLWorksheet ws))
                 {
                     var range = ws.NamedRange(name);
                     return range ?? NamedRange(name);
@@ -751,11 +750,7 @@
             if (namedRange != null)
                 return namedRange.Ranges.FirstOrDefault();
             else
-            {
-                IXLWorksheet ws;
-                var r = RangeFromFullAddress(range, out ws);
-                return r;
-            }
+                return RangeFromFullAddress(range, out IXLWorksheet ws);
         }
 
         public IXLRanges Ranges(String ranges)
diff --git a/ClosedXML/Excel/XLWorkbook_Load.cs b/ClosedXML/Excel/XLWorkbook_Load.cs
index d4182b0..95c292a 100644
--- a/ClosedXML/Excel/XLWorkbook_Load.cs
+++ b/ClosedXML/Excel/XLWorkbook_Load.cs
@@ -1227,8 +1227,7 @@
                         }
                         else
                         {
-                            string sheetName, sheetArea;
-                            ParseReference(area, out sheetName, out sheetArea);
+                            ParseReference(area, out String sheetName, out String sheetArea);
                             if (!(sheetArea.Equals("#REF") || sheetArea.EndsWith("#REF!") || sheetArea.Length == 0 || sheetName.Length == 0))
                                 WorksheetsInternal.Worksheet(sheetName).PageSetup.PrintAreas.Add(sheetArea);
                         }
@@ -1297,8 +1296,7 @@
 
         private void SetColumnsOrRowsToRepeat(string area)
         {
-            string sheetName, sheetArea;
-            ParseReference(area, out sheetName, out sheetArea);
+            ParseReference(area, out String sheetName, out String sheetArea);
             if (sheetArea.Equals("#REF")) return;
             if (IsColReference(sheetArea))
                 WorksheetsInternal.Worksheet(sheetName).PageSetup.SetColumnsToRepeatAtLeft(sheetArea);
@@ -1843,9 +1841,8 @@
                     Boolean isText = false;
                     foreach (var filter in filterColumn.CustomFilters.OfType<CustomFilter>())
                     {
-                        Double dTest;
                         String val = filter.Val.Value;
-                        if (!Double.TryParse(val, out dTest))
+                        if (!Double.TryParse(val, out Double dTest))
                         {
                             isText = true;
                             break;
@@ -1907,9 +1904,8 @@
                     Boolean isText = false;
                     foreach (var filter in filterColumn.Filters.OfType<Filter>())
                     {
-                        Double dTest;
                         String val = filter.Val.Value;
-                        if (!Double.TryParse(val, out dTest))
+                        if (!Double.TryParse(val, out Double dTest))
                         {
                             isText = true;
                             break;
diff --git a/ClosedXML/Excel/XLWorkbook_Save.cs b/ClosedXML/Excel/XLWorkbook_Save.cs
index 750e924..5c694a8 100644
--- a/ClosedXML/Excel/XLWorkbook_Save.cs
+++ b/ClosedXML/Excel/XLWorkbook_Save.cs
@@ -2118,8 +2118,7 @@
                                 .Cast<object>()
                                 .ToArray();
 
-                        int val;
-                        var allInteger = ptfi.DistinctValues.All(v => int.TryParse(v.ToString(), out val));
+                        var allInteger = ptfi.DistinctValues.All(v => int.TryParse(v.ToString(), out int val));
                         if (allInteger) sharedItems.ContainsInteger = true;
 
                         pti.Fields.Add(xlpf.SourceName, ptfi);
@@ -2779,8 +2778,7 @@
                 var comment = new Comment { Reference = c.Address.ToStringRelative() };
                 var authorName = c.Comment.Author;
 
-                Int32 authorId;
-                if (!authorsDict.TryGetValue(authorName, out authorId))
+                if (!authorsDict.TryGetValue(authorName, out int authorId))
                 {
                     authorId = authorsDict.Count;
                     authorsDict.Add(authorName, authorId);
diff --git a/ClosedXML/Excel/XLWorksheet.cs b/ClosedXML/Excel/XLWorksheet.cs
index d5cc301..2f02040 100644
--- a/ClosedXML/Excel/XLWorksheet.cs
+++ b/ClosedXML/Excel/XLWorksheet.cs
@@ -306,8 +306,7 @@
                     lastColumn = tPair;
                 }
 
-                Int32 tmp;
-                if (Int32.TryParse(firstColumn, out tmp))
+                if (Int32.TryParse(firstColumn, out int tmp))
                 {
                     foreach (IXLColumn col in Columns(Int32.Parse(firstColumn), Int32.Parse(lastColumn)))
                         retVal.Add((XLColumn)col);
@@ -1350,8 +1349,7 @@
                                                                  XLHelper.MaxRowNumber));
 
             IXLStyle style;
-            XLRow rowToUse;
-            if (Internals.RowsCollection.TryGetValue(row, out rowToUse))
+            if (Internals.RowsCollection.TryGetValue(row, out XLRow rowToUse))
                 style = rowToUse.Style;
             else
             {
diff --git a/ClosedXML/Excel/XLWorksheets.cs b/ClosedXML/Excel/XLWorksheets.cs
index 94cace4..14c22bd 100644
--- a/ClosedXML/Excel/XLWorksheets.cs
+++ b/ClosedXML/Excel/XLWorksheets.cs
@@ -47,8 +47,7 @@
 
         public bool TryGetWorksheet(string sheetName, out IXLWorksheet worksheet)
         {
-            XLWorksheet w;
-            if (_worksheets.TryGetValue(sheetName.UnescapeSheetName().ToLowerInvariant(), out w))
+            if (_worksheets.TryGetValue(sheetName.UnescapeSheetName().ToLowerInvariant(), out XLWorksheet w))
             {
                 worksheet = w;
                 return true;
@@ -61,9 +60,7 @@
         {
             sheetName = sheetName.UnescapeSheetName();
 
-            XLWorksheet w;
-
-            if (_worksheets.TryGetValue(sheetName.ToLowerInvariant(), out w))
+            if (_worksheets.TryGetValue(sheetName.ToLowerInvariant(), out XLWorksheet w))
                 return w;
 
             var wss = _worksheets.Where(ws => string.Equals(ws.Key, sheetName, StringComparison.OrdinalIgnoreCase));
diff --git a/ClosedXML/Extensions.cs b/ClosedXML/Extensions.cs
index 5d14a91..8af0aac 100644
--- a/ClosedXML/Extensions.cs
+++ b/ClosedXML/Extensions.cs
@@ -251,8 +251,7 @@
 
         private static Font GetCachedFont(IXLFontBase fontBase, Dictionary<IXLFontBase, Font> fontCache)
         {
-            Font font;
-            if (!fontCache.TryGetValue(fontBase, out font))
+            if (!fontCache.TryGetValue(fontBase, out Font font))
             {
                 font = new Font(fontBase.FontName, (float)fontBase.FontSize, GetFontStyle(fontBase));
                 fontCache.Add(fontBase, font);
diff --git a/ClosedXML/XLHelper.cs b/ClosedXML/XLHelper.cs
index ea324cd..652dabe 100644
--- a/ClosedXML/XLHelper.cs
+++ b/ClosedXML/XLHelper.cs
@@ -158,8 +158,7 @@
 
         public static bool IsValidRow(string rowString)
         {
-            Int32 row;
-            if (Int32.TryParse(rowString, out row))
+            if (Int32.TryParse(rowString, out int row))
                 return row > 0 && row <= MaxRowNumber;
             return false;
         }
diff --git a/ClosedXML_Tests/Excel/NamedRanges/NamedRangesTests.cs b/ClosedXML_Tests/Excel/NamedRanges/NamedRangesTests.cs
index afe5c7b..f406d08 100644
--- a/ClosedXML_Tests/Excel/NamedRanges/NamedRangesTests.cs
+++ b/ClosedXML_Tests/Excel/NamedRanges/NamedRangesTests.cs
@@ -41,7 +41,7 @@
         public void WbContainsWsNamedRange()
         {
             var wb = new XLWorkbook();
-            IXLWorksheet ws = wb.AddWorksheet("Sheet1");
+            var ws = wb.AddWorksheet("Sheet1");
             ws.FirstCell().AddToNamed("Name", XLScope.Worksheet);
 
             Assert.IsTrue(wb.NamedRanges.Contains("Sheet1!Name"));
@@ -50,13 +50,11 @@
             Assert.IsNotNull(wb.NamedRange("Sheet1!Name"));
             Assert.IsNull(wb.NamedRange("Sheet1!NameX"));
 
-            IXLNamedRange range1;
-            Boolean result1 = wb.NamedRanges.TryGetValue("Sheet1!Name", out range1);
+            Boolean result1 = wb.NamedRanges.TryGetValue("Sheet1!Name", out IXLNamedRange range1);
             Assert.IsTrue(result1);
             Assert.IsNotNull(range1);
 
-            IXLNamedRange range2;
-            Boolean result2 = wb.NamedRanges.TryGetValue("Sheet1!NameX", out range2);
+            Boolean result2 = wb.NamedRanges.TryGetValue("Sheet1!NameX", out IXLNamedRange range2);
             Assert.IsFalse(result2);
             Assert.IsNull(range2);
         }
@@ -65,7 +63,7 @@
         public void WorkbookContainsNamedRange()
         {
             var wb = new XLWorkbook();
-            IXLWorksheet ws = wb.AddWorksheet("Sheet1");
+            var ws = wb.AddWorksheet("Sheet1");
             ws.FirstCell().AddToNamed("Name");
 
             Assert.IsTrue(wb.NamedRanges.Contains("Name"));
@@ -74,13 +72,11 @@
             Assert.IsNotNull(wb.NamedRange("Name"));
             Assert.IsNull(wb.NamedRange("NameX"));
 
-            IXLNamedRange range1;
-            Boolean result1 = wb.NamedRanges.TryGetValue("Name", out range1);
+            Boolean result1 = wb.NamedRanges.TryGetValue("Name", out IXLNamedRange range1);
             Assert.IsTrue(result1);
             Assert.IsNotNull(range1);
 
-            IXLNamedRange range2;
-            Boolean result2 = wb.NamedRanges.TryGetValue("NameX", out range2);
+            Boolean result2 = wb.NamedRanges.TryGetValue("NameX", out IXLNamedRange range2);
             Assert.IsFalse(result2);
             Assert.IsNull(range2);
         }
@@ -97,13 +93,11 @@
             Assert.IsNotNull(ws.NamedRange("Name"));
             Assert.IsNull(ws.NamedRange("NameX"));
 
-            IXLNamedRange range1;
-            Boolean result1 = ws.NamedRanges.TryGetValue("Name", out range1);
+            Boolean result1 = ws.NamedRanges.TryGetValue("Name", out IXLNamedRange range1);
             Assert.IsTrue(result1);
             Assert.IsNotNull(range1);
 
-            IXLNamedRange range2;
-            Boolean result2 = ws.NamedRanges.TryGetValue("NameX", out range2);
+            Boolean result2 = ws.NamedRanges.TryGetValue("NameX", out IXLNamedRange range2);
             Assert.IsFalse(result2);
             Assert.IsNull(range2);
         }
diff --git a/ClosedXML_Tests/Excel/Worksheets/XLWorksheetTests.cs b/ClosedXML_Tests/Excel/Worksheets/XLWorksheetTests.cs
index f87f008..632a27c 100644
--- a/ClosedXML_Tests/Excel/Worksheets/XLWorksheetTests.cs
+++ b/ClosedXML_Tests/Excel/Worksheets/XLWorksheetTests.cs
@@ -170,8 +170,8 @@
         {
             using (var wb = new XLWorkbook())
             {
-                var ws1 = wb.AddWorksheet("Sheet1");
-                var ws2 = wb.AddWorksheet("Sheet2");
+                wb.AddWorksheet("Sheet1");
+                wb.AddWorksheet("Sheet2");
 
                 IXLWorksheet ws;
                 Assert.IsTrue(wb.Worksheets.TryGetWorksheet("Sheet1", out ws));
diff --git a/ClosedXML_Tests/ExcelDocsComparerTests.cs b/ClosedXML_Tests/ExcelDocsComparerTests.cs
index 42677eb..dd32014 100644
--- a/ClosedXML_Tests/ExcelDocsComparerTests.cs
+++ b/ClosedXML_Tests/ExcelDocsComparerTests.cs
@@ -16,8 +16,7 @@
             {
                 new BasicTable().Create(left);
                 new BasicTable().Create(right);
-                string message;
-                Assert.IsTrue(ExcelDocsComparer.Compare(left, right, out message));
+                Assert.IsTrue(ExcelDocsComparer.Compare(left, right, out string message));
             }
             finally
             {
@@ -42,8 +41,7 @@
                 new BasicTable().Create(left);
                 new HelloWorld().Create(right);
 
-                string message;
-                Assert.IsFalse(ExcelDocsComparer.Compare(left, right, out message));
+                Assert.IsFalse(ExcelDocsComparer.Compare(left, right, out string message));
             }
             finally
             {
diff --git a/ClosedXML_Tests/TestHelper.cs b/ClosedXML_Tests/TestHelper.cs
index 476247c..0655c5a 100644
--- a/ClosedXML_Tests/TestHelper.cs
+++ b/ClosedXML_Tests/TestHelper.cs
@@ -83,8 +83,7 @@
                 using (var streamExpected = _extractor.ReadFileFromResToStream(resourcePath))
                 using (var streamActual = File.OpenRead(filePath2))
                 {
-                    string message;
-                    var success = ExcelDocsComparer.Compare(streamActual, streamExpected, out message);
+                    var success = ExcelDocsComparer.Compare(streamActual, streamExpected, out string message);
                     var formattedMessage =
                         String.Format(
                             "Actual file '{0}' is different than the expected file '{1}'. The difference is: '{2}'",
@@ -120,8 +119,7 @@
                 using (var streamExpected = _extractor.ReadFileFromResToStream(resourcePath))
                 using (var streamActual = File.OpenRead(filePath2))
                 {
-                    string message;
-                    var success = ExcelDocsComparer.Compare(streamActual, streamExpected, out message);
+                    var success = ExcelDocsComparer.Compare(streamActual, streamExpected, out string message);
                     var formattedMessage =
                         String.Format(
                             "Actual file '{0}' is different than the expected file '{1}'. The difference is: '{2}'",
diff --git a/ClosedXML_Tests/Utils/PackageHelper.cs b/ClosedXML_Tests/Utils/PackageHelper.cs
index f4f43cd..1e642a6 100644
--- a/ClosedXML_Tests/Utils/PackageHelper.cs
+++ b/ClosedXML_Tests/Utils/PackageHelper.cs
@@ -322,8 +322,7 @@
                 {
                     continue;
                 }
-                PartPair pair;
-                if (pairs.TryGetValue(part.Uri, out pair))
+                if (pairs.TryGetValue(part.Uri, out PartPair pair))
                 {
                     pair.Status = CompareStatus.Equal;
                 }
diff --git a/ClosedXML_Tests/Utils/ResourceFileExtractor.cs b/ClosedXML_Tests/Utils/ResourceFileExtractor.cs
index c6c4c9a..e982ee4 100644
--- a/ClosedXML_Tests/Utils/ResourceFileExtractor.cs
+++ b/ClosedXML_Tests/Utils/ResourceFileExtractor.cs
@@ -22,10 +22,9 @@
         {
             get
             {
-                ResourceFileExtractor _return;
                 Assembly _assembly = Assembly.GetCallingAssembly();
                 string _key = _assembly.GetName().FullName;
-                if (!ms_defaultExtractors.TryGetValue(_key, out _return))
+                if (!ms_defaultExtractors.TryGetValue(_key, out ResourceFileExtractor _return))
                 {
                     lock (ms_defaultExtractors)
                     {
@@ -235,4 +234,4 @@
         }
         #endregion
     }
-}
\ No newline at end of file
+}