Is there a syntactic sugar to write the following code in a better way?

if (x != null && x.y != null) {
   ...things that use x!.y
}

I could write something like

if (x?.y != null) {
   ...things that use x!.y
}

but I don't think that is the same thing

CodePudding user response：

You should not use ! if you can instead write better code:

final item = x?.y;
if (item != null) {
   // ...things that use item,
   // a local variable elevated to non-null inside the scope of the if,
   // no ! operator neccessary
}

CodePudding user response：

The x?.y != null is mostly equivalent to x != null && x.y != null except that it doesn't promote x to non-null.

To actually promote a variable, you need to test the variable directly.

I'd do:

if (x != null) {  
  var y = x.y;
  if (y != null) {
    // use y
  }
}

in order to get promotion on both. Or do as @nvoght says and use x?.y to get the value into a variable, then promote that variable.