Earlier quoted context omitted.
I don't understand what you are talking about. The syntactic sugar already exits before this change. That is to say, in a version f C# without the feature, you can write this: a.b?.c = foo It's not not well-formed semantically. What the change does is allow the above to be well-formed semantically. If b isn't null, then it behaves like a.b.c = foo. Otherwise, the value of foo is discarded. (Perhaps foo isn't even eva…
> The idea that there is no change in semantics, but only syntactic sugar is exactly backwards. > The syntactic sugar already exits before this change. That is to say, in a version f C# without the feature, you can write this: a.b?.c = foo You cannot. The semantics is conditional assignment, which already exists in the language. Hence the article repeatedly bludgeoning you with pairs of code snippets - whose semantic…
a.b?.c = foo
Main.cs(19,9): error CS0131: The left-hand side of an assignment must be a variable, property or indexer
This error got replaced with code which allows that type of expression, and generates code for it rather than a diagnostic.
I can't say for sure that they did zero parser work for the feature, but it sure looks like in principle, you do not have to, for this case, given that it already parses.
(If they have a parser which handles semantic attributes in teh grammar like "assignable expression", then of course that gets adjusted.)
For reference:
using System;
public class A
{
public B b { get; set; }
}
public class B
{
public int? c { get; set; }
}
public class Program.
{
public static void Main()
{
A a = new A { };
int foo = 42;
a.b?.c = foo;
}
}