Propоsal: Allow simultaneous use of this (...) and base (...) when creating a class constructor

[DeveloperLookBook]

Example:

class A {
   private string PropA {get; set;}
   public A() {}
   public A(string propA) this.PropA = propA;
}

class B : A {
   private string PropB_1 {get; set;}
   private string PropB_2 {get; set;}

   public B(string propB_1) => this.PropB_1 = propB_1;
   public B(string propB_1, string propB_2, string propA) : this(propB_1), base(A) // simultaneous use of this (...) and base (...) 
   {
       this.PropB_2 = propB_2;
   }
}

[svick]

I don't think I like that adding base(propA) effectively changes what the preceding this(propB_1) means.

Also, I'm not sure there's a good way to represent this in IL: when B(string, string, string) calls B(string), it doesn't get a choice to tell it to skip calling A().

[HaloFour]

A constructor must either call a base constructor or another constructor on the current class. It cannot call both as the base constructor must only be called once.

You can very easily solve your problem above with some minor refactoring. More complicated examples can be solved through helper methods.