diff --git a/src/Sudoku.Console/BulkSolver.cs b/src/Sudoku.Console/BulkSolver.cs
index 83a6b10..a2e0ad4 100644
--- a/src/Sudoku.Console/BulkSolver.cs
+++ b/src/Sudoku.Console/BulkSolver.cs
@@ -76,7 +76,7 @@ public void Solve(bool quiet = false, bool noSummary = false)
 
                         var clues = _puzzles[i].Clues;
 
-                        if (! _timings.TryGetValue(clues, out (int Count, double Elapsed) value))
+                        if (! _timings.TryGetValue(clues, out var value))
                         {
                             value = (0, 0);
 
@@ -126,7 +126,7 @@ public void Solve(bool quiet = false, bool noSummary = false)
 
                         var clues = _puzzles[i].Clues;
 
-                        if (! _timings.TryGetValue(clues, out (int Count, double Elapsed) value))
+                        if (! _timings.TryGetValue(clues, out var value))
                         {
                             value = (0, 0);
 
diff --git a/src/Sudoku.Console/TreeGenerator.cs b/src/Sudoku.Console/TreeGenerator.cs
index 1205f8b..9e5c6cc 100644
--- a/src/Sudoku.Console/TreeGenerator.cs
+++ b/src/Sudoku.Console/TreeGenerator.cs
@@ -167,7 +167,7 @@ private static Node GenerateNodes(int[] puzzle, SudokuResult result)
 
         var root = node;
 
-        Node solved = node;
+        var solved = node;
 
         var backtracking = false;
         
diff --git a/src/Sudoku/Generator.cs b/src/Sudoku/Generator.cs
index ec1aae6..e3b1dc4 100644
--- a/src/Sudoku/Generator.cs
+++ b/src/Sudoku/Generator.cs
@@ -81,12 +81,7 @@ private bool CreateSolvedPuzzle(Span<int> puzzle, int cell = 0)
 
             if (puzzle.IsValidSudoku())
             {
-                if (cell == 80)
-                {
-                    return true;
-                }
-                
-                return CreateSolvedPuzzle(puzzle, cell + 1);
+                return cell == 80 || CreateSolvedPuzzle(puzzle, cell + 1);
             }
         }
         
diff --git a/src/Sudoku/Solver.cs b/src/Sudoku/Solver.cs
index 1fec1a5..4e6515e 100644
--- a/src/Sudoku/Solver.cs
+++ b/src/Sudoku/Solver.cs
@@ -79,7 +79,7 @@ public SudokuResult Solve(int[] puzzle)
             return new SudokuResult(_workingCopy, false, _steps, stopwatch.Elapsed.TotalMicroseconds, null, null, $"Insufficient number of clues: {81 - _score}");
         }
 
-        _history = _historyType != HistoryType.None ? new List<Move>() : null;
+        _history = _historyType != HistoryType.None ? [] : null;
 
         var candidates = GetSectionCandidates(span);