C# 13 has this via the field keyword (as preview feature): https://learn.microsoft.com/en-us/dotnet/csharp/language-ref...
It's pretty similar to what PHP provides here, except that PHP uses "$this->propname =" and C# uses "field =".
Edit: As someone involved in the RFC, it's somewhat funny, because we considered a special variable like "$field" or "$value" too magic, and C# does just that with a field keyword.