Cache zero values to reduce boxing in PrimitiveType.DefaultValue

src/NHibernate/Async/Type/Int16Type.cs

@@ -24,8 +24,6 @@ namespace NHibernate.Type
 	public partial class Int16Type : PrimitiveType, IDiscriminatorType, IVersionType
 	{
 
-		#region IVersionType Members
-
 		public virtual Task<object> NextAsync(object current, ISessionImplementor session, CancellationToken cancellationToken)
 		{
 			if (cancellationToken.IsCancellationRequested)
@@ -57,7 +55,5 @@ public virtual Task<object> SeedAsync(ISessionImplementor session, CancellationT
 				return Task.FromException<object>(ex);
 			}
 		}
-
-		#endregion
 	}
 }

src/NHibernate/Type/AbstractCharType.cs

@@ -11,14 +11,13 @@ namespace NHibernate.Type
 	[Serializable]
 	public abstract class AbstractCharType : PrimitiveType, IDiscriminatorType
 	{
-		public AbstractCharType(SqlType sqlType)
-			: base(sqlType) {}
-
-		public override object DefaultValue
+		/// <summary />
+		public AbstractCharType(SqlType sqlType) : base(sqlType)
 		{
-			get { throw new NotSupportedException("not a valid id type"); }
 		}
 
+		public override object DefaultValue => throw new NotSupportedException("not a valid id type");
+
 		public override object Get(DbDataReader rs, int index, ISessionImplementor session)
 		{
 			string dbValue = Convert.ToString(rs[index]);
@@ -30,15 +29,9 @@ public override object Get(DbDataReader rs, int index, ISessionImplementor sessi
 			return '\0'; // This line should never be executed
 		}
 
-		public override System.Type PrimitiveClass
-		{
-			get { return typeof(char); }
-		}
+		public override System.Type PrimitiveClass => typeof(char);
 
-		public override System.Type ReturnedClass
-		{
-			get { return typeof(char); }
-		}
+		public override System.Type ReturnedClass => typeof(char);
 
 		public override void Set(DbCommand cmd, object value, int index, ISessionImplementor session)
 		{

src/NHibernate/Type/AbstractDateTimeType.cs

@@ -14,7 +14,7 @@ namespace NHibernate.Type
 	[Serializable]
 	public abstract partial class AbstractDateTimeType : PrimitiveType, IIdentifierType, ILiteralType, IVersionType
 	{
-		private static readonly DateTime BaseDateValue = DateTime.MinValue;
+		private static readonly object BaseDateValue = DateTime.MinValue;
 
 		/// <summary>
 		/// Returns the <see cref="DateTimeKind" /> for the type.
@@ -31,17 +31,12 @@ public abstract partial class AbstractDateTimeType : PrimitiveType, IIdentifierT
 		/// <see cref="DateTime.Now" /> otherwise.</value>
 		protected virtual DateTime Now => Kind == DateTimeKind.Utc ? DateTime.UtcNow : DateTime.Now;
 
-		/// <summary>
-		/// Default constructor.
-		/// </summary>
-		protected AbstractDateTimeType() : base(SqlTypeFactory.DateTime)
+		/// <summary />
+		protected AbstractDateTimeType() : this(SqlTypeFactory.DateTime)
 		{
 		}
 
-		/// <summary>
-		/// Constructor for overriding the default <see cref="SqlType"/>.
-		/// </summary>
-		/// <param name="sqlTypeDateTime">The <see cref="SqlType"/> to use.</param>
+		/// <summary />
 		protected AbstractDateTimeType(SqlType sqlTypeDateTime) : base(sqlTypeDateTime)
 		{
 		}

src/NHibernate/Type/ByteType.cs

@@ -15,10 +15,10 @@ namespace NHibernate.Type
 	[Serializable]
 	public partial class ByteType : PrimitiveType, IDiscriminatorType, IVersionType
 	{
-		private static readonly byte ZERO = 0;
+		private static readonly object ZeroObject = (byte) 0;
 
-		public ByteType()
-			: base(SqlTypeFactory.Byte)
+		/// <summary />
+		public ByteType() : base(SqlTypeFactory.Byte)
 		{
 		}
 
@@ -32,26 +32,17 @@ public override object Get(DbDataReader rs, int index, ISessionImplementor sessi
 			};
 		}
 
-		public override System.Type ReturnedClass
-		{
-			get { return typeof(byte); }
-		}
+		public override System.Type ReturnedClass => typeof(byte);
 
-		public override System.Type PrimitiveClass
-		{
-			get { return typeof(byte); }
-		}
+		public override System.Type PrimitiveClass => typeof(byte);
 
 		public override void Set(DbCommand cmd, object value, int index, ISessionImplementor session)
 		{
 			var dp = cmd.Parameters[index];
 			dp.Value = dp.DbType == DbType.Int16 ? Convert.ToInt16(value) : Convert.ToByte(value);
 		}
 
-		public override string Name
-		{
-			get { return "Byte"; }
-		}
+		public override string Name => "Byte";
 
 		public override string ObjectToSQLString(object value, Dialect.Dialect dialect)
 		{
@@ -84,17 +75,11 @@ public virtual object Next(object current, ISessionImplementor session)
 
 		public virtual object Seed(ISessionImplementor session)
 		{
-			return ZERO;
+			return ZeroObject;
 		}
 
-		public IComparer Comparator
-		{
-			get { return Comparer.DefaultInvariant; }
-		}
+		public IComparer Comparator => Comparer.DefaultInvariant;
 
-		public override object DefaultValue
-		{
-			get { return ZERO; }
-		}
+		public override object DefaultValue => ZeroObject;
 	}
 }

src/NHibernate/Type/DateTimeOffSetType.cs

@@ -14,47 +14,26 @@ namespace NHibernate.Type
 	[Serializable]
 	public partial class DateTimeOffsetType : PrimitiveType, IIdentifierType, ILiteralType, IVersionType
 	{
-		static readonly DateTimeOffset BaseDateValue = DateTimeOffset.MinValue;
+		private static readonly object BaseDateValue = DateTimeOffset.MinValue;
 
-		/// <summary>
-		/// Default constructor.
-		/// </summary>
 		public DateTimeOffsetType() : base(SqlTypeFactory.DateTimeOffSet)
 		{
 		}
 
-		/// <summary>
-		/// Constructor for specifying a datetimeoffset with a scale. Use <see cref="SqlTypeFactory.GetDateTimeOffset"/>.
-		/// </summary>
-		/// <param name="sqlType">The sql type to use for the type.</param>
+		/// <summary />
 		public DateTimeOffsetType(DateTimeOffsetSqlType sqlType) : base(sqlType)
 		{
 		}
 
-		public override string Name
-		{
-			get { return "DateTimeOffset"; }
-		}
+		public override string Name => "DateTimeOffset";
 
-		public override System.Type ReturnedClass
-		{
-			get { return typeof (DateTimeOffset); }
-		}
+		public override System.Type ReturnedClass => typeof (DateTimeOffset);
 
-		public override System.Type PrimitiveClass
-		{
-			get { return typeof (DateTimeOffset); }
-		}
+		public override System.Type PrimitiveClass => typeof (DateTimeOffset);
 
-		public override object DefaultValue
-		{
-			get { return BaseDateValue; }
-		}
+		public override object DefaultValue => BaseDateValue;
 
-		public IComparer Comparator
-		{
-			get { return Comparer<DateTimeOffset>.Default; }
-		}
+		public IComparer Comparator => Comparer<DateTimeOffset>.Default;
 
 		public override void Set(DbCommand st, object value, int index, ISessionImplementor session)
 		{

src/NHibernate/Type/DateType.cs

@@ -21,11 +21,12 @@ public class DateType : AbstractDateTimeType, IParameterizedType
 		// Since v5.0
 		[Obsolete("Use DateTime.MinValue.")]
 		public static readonly DateTime BaseDateValue = DateTime.MinValue;
-		private DateTime customBaseDate = _baseDateValue;
 
 		private static readonly DateTime _baseDateValue = DateTime.MinValue;
 
-		/// <summary>Default constructor</summary>
+		private object customBaseDate = _baseDateValue;
+
+		/// <summary />
 		public DateType() : base(SqlTypeFactory.Date)
 		{
 		}

src/NHibernate/Type/DecimalType.cs

@@ -13,11 +13,15 @@ namespace NHibernate.Type
 	[Serializable]
 	public class DecimalType : PrimitiveType, IIdentifierType
 	{
+		private static readonly object ZeroObject = 0m;
+
+		/// <summary />
 		public DecimalType()
 			: this(SqlTypeFactory.Decimal)
 		{
 		}
 
+		/// <summary />
 		public DecimalType(SqlType sqlType) : base(sqlType)
 		{
 		}
@@ -27,30 +31,18 @@ public override object Get(DbDataReader rs, int index, ISessionImplementor sessi
 			return Convert.ToDecimal(rs[index]);
 		}
 
-		public override System.Type ReturnedClass
-		{
-			get { return typeof(Decimal); }
-		}
+		public override System.Type ReturnedClass => typeof(Decimal);
 
 		public override void Set(DbCommand st, object value, int index, ISessionImplementor session)
 		{
 			st.Parameters[index].Value = Convert.ToDecimal(value);
 		}
 
-		public override string Name
-		{
-			get { return "Decimal"; }
-		}
+		public override string Name => "Decimal";
 
-		public override System.Type PrimitiveClass
-		{
-			get { return typeof (Decimal); }
-		}
+		public override System.Type PrimitiveClass => typeof (Decimal);
 
-		public override object DefaultValue
-		{
-			get { return 0m; }
-		}
+		public override object DefaultValue => ZeroObject;
 
 		// Since 5.2
 		[Obsolete("This method has no more usages and will be removed in a future version.")]

src/NHibernate/Type/DoubleType.cs

@@ -14,12 +14,17 @@ namespace NHibernate.Type
 	[Serializable]
 	public class DoubleType : PrimitiveType
 	{
-		/// <summary></summary>
+		private static readonly object ZeroObject = 0D;
+
+		/// <summary />
 		public DoubleType() : base(SqlTypeFactory.Double)
 		{
 		}
 
-		public DoubleType(SqlType sqlType) : base(sqlType) {}
+		/// <summary />
+		public DoubleType(SqlType sqlType) : base(sqlType)
+		{
+		}
 
 		public override object Get(DbDataReader rs, int index, ISessionImplementor session)
 		{
@@ -31,21 +36,15 @@ public override object Get(DbDataReader rs, int index, ISessionImplementor sessi
 		}
 
 		/// <summary></summary>
-		public override System.Type ReturnedClass
-		{
-			get { return typeof(double); }
-		}
+		public override System.Type ReturnedClass => typeof(double);
 
 		public override void Set(DbCommand st, object value, int index, ISessionImplementor session)
 		{
 			st.Parameters[index].Value = Convert.ToDouble(value);
 		}
 
 		/// <summary></summary>
-		public override string Name
-		{
-			get { return "Double"; }
-		}
+		public override string Name => "Double";
 
 		// Since 5.2
 		[Obsolete("This method has no more usages and will be removed in a future version.")]
@@ -54,15 +53,9 @@ public override object FromStringValue(string xml)
 			return double.Parse(xml);
 		}
 
-		public override System.Type PrimitiveClass
-		{
-			get { return typeof(double); }
-		}
+		public override System.Type PrimitiveClass => typeof(double);
 
-		public override object DefaultValue
-		{
-			get { return 0D; }
-		}
+		public override object DefaultValue => ZeroObject;
 
 		public override string ObjectToSQLString(object value, Dialect.Dialect dialect)
 		{

src/NHibernate/Type/GuidType.cs

@@ -13,7 +13,9 @@ namespace NHibernate.Type
 	[Serializable]
 	public class GuidType : PrimitiveType, IDiscriminatorType
 	{
-		/// <summary></summary>
+		private static readonly object EmptyObject = Guid.Empty;
+
+		/// <summary />
 		public GuidType() : base(SqlTypeFactory.Guid)
 		{
 		}
@@ -34,10 +36,7 @@ public override object Get(DbDataReader rs, int index, ISessionImplementor sessi
 		}
 
 		/// <summary></summary>
-		public override System.Type ReturnedClass
-		{
-			get { return typeof(Guid); }
-		}
+		public override System.Type ReturnedClass => typeof(Guid);
 
 		public override void Set(DbCommand cmd, object value, int index, ISessionImplementor session)
 		{
@@ -47,10 +46,7 @@ public override void Set(DbCommand cmd, object value, int index, ISessionImpleme
 		}
 
 		/// <summary></summary>
-		public override string Name
-		{
-			get { return "Guid"; }
-		}
+		public override string Name => "Guid";
 
 		// Since 5.2
 		[Obsolete("This method has no more usages and will be removed in a future version.")]
@@ -71,15 +67,9 @@ public object StringToObject(string xml)
 #pragma warning restore 618
 		}
 
-		public override System.Type PrimitiveClass
-		{
-			get { return typeof(Guid); }
-		}
+		public override System.Type PrimitiveClass => typeof(Guid);
 
-		public override object DefaultValue
-		{
-			get { return Guid.Empty; }
-		}
+		public override object DefaultValue => EmptyObject;
 
 		public override string ObjectToSQLString(object value, Dialect.Dialect dialect)
 		{