Fix type casts

Author: Joy-less

SQLiteSharp.Tests/ConvertTest.cs

@@ -0,0 +1,30 @@
+namespace SQLiteSharp.Tests;
+
+public class ConvertTest {
+    [Fact]
+    public void Test1() {
+        // Open a database connection
+        using SqliteConnection Connection = new(":memory:");
+
+        // Create a table for a class
+        SqliteTable<GameEnemy> GameEnemies = Connection.GetTable<GameEnemy>("GameEnemies");
+
+        // Insert items into the table
+        GameEnemies.Insert(new GameEnemy() {
+            Type = GameEnemyType.Zombie,
+        });
+
+        // Find one item in the table matching a predicate
+        GameEnemies.FindOne(GameEnemy => GameEnemy.Type == GameEnemyType.Zombie).ShouldNotBeNull();
+    }
+}
+
+public class GameEnemy {
+    public GameEnemyType Type { get; set; }
+}
+
+public enum GameEnemyType {
+    Slime,
+    Zombie,
+    Skeleton,
+}

SQLiteSharp/SqlBuilder.cs

@@ -403,6 +403,10 @@ public string ExpressionToSql(Expression expression, ParameterExpression rowExpr
 
             // Unary (!a)
             case UnaryExpression unaryExpression:
+                if (unaryExpression.NodeType is ExpressionType.Convert or ExpressionType.ConvertChecked) {
+                    // Casts not necessary with SQLite's dynamic typing
+                    return ExpressionToSql(unaryExpression.Operand, rowExpression);
+                }
                 return $"({OperatorToSql(unaryExpression.NodeType)} {ExpressionToSql(unaryExpression.Operand, rowExpression)})";
 
             // Binary (a == b)