public static void CheckConstant(ConstantExpression value, bool isRelational)
{
if (value.Value == null)
{
if (isRelational)
{
throw Error.CannotUseNullValueInRelationalPattern();
}
return;
}
if (value.Type.IsNullableType() && value.Value != null)
{
throw Error.InvalidPatternConstantType(value.Type);
}
if (value.Type == typeof(IntPtr) || value.Type == typeof(UIntPtr))
{
return;
}
switch (Type.GetTypeCode(value.Type.GetNonNullableType()))
{
case TypeCode.Char:
case TypeCode.SByte:
case TypeCode.Byte:
case TypeCode.Int16:
case TypeCode.UInt16:
case TypeCode.Int32:
case TypeCode.UInt32:
case TypeCode.Int64:
case TypeCode.UInt64:
case TypeCode.Decimal:
break;
case TypeCode.Single:
if (isRelational && float.IsNaN((float)value.Value))
{
throw Error.CannotUsePatternConstantNaN();
}
break;
case TypeCode.Double:
if (isRelational && double.IsNaN((double)value.Value))
{
throw Error.CannotUsePatternConstantNaN();
}
break;
case TypeCode.Boolean:
case TypeCode.String:
if (isRelational)
{
throw Error.InvalidRelationalPatternConstantType(value.Type);
}
break;
default:
throw Error.InvalidPatternConstantType(value.Type);
}
}