C# 先週の土曜日を取得する

先週の土曜日を取得
            var vDay = d.AddDays(-(int)d.DayOfWeek - 1);

先週の金曜日を取得
            var vDay = d.AddDays(-(int)d.DayOfWeek - 2);

dlangide build error

change to this in project.d file
bool isValidProjectName(in string s) pure {
if (s.empty)
return false;
return reduce!q{ a && (b == '_' || b == '-' || (b>='A' && b <='Z' || b>='a' && b <='z' || b>='0' && b <='9')) }(true, s);
}
bool isValidModuleName(in string s) pure {
if (s.empty)
return false;
return reduce!q{ a && (b == '_' || (b>='A' && b <='Z' || b>='a' && b <='z' || b>='0' && b <='9')) }(true, s);
}
bool isValidFileName(in string s) pure {
if (s.empty)
return false;
return reduce!q{ a && (b == '_' || b == '.' || b == '-' || (b>='A' && b <='Z' || b>='a' && b <='z' || b>='0' && b <='9')) }(true, s);
}