Allow seeing the "Return value" of an operation in the debug panel

[MiniSuperDev]

In JS you can see the Return value of different operations in the debug panel in the "Return value"

I would like to be able to do the same in Dart.

So instead of this

int sum(int a, int b) {
  final result = a + b;
  return result; // break point to se the "Return value" but you need to create a local variable.
}

We could make this

ìnt sum(int a, int b)=> a + b; // with this feature you can make "Step over" or other steps and see "Return value" without create local variable.

More info:
https://stackoverflow.com/questions/47200659/watching-return-values-in-visual-studio-code

Thanks

[DanTup]

@bkonyi is there an existing way to get at the return value for a function through the VM Service?

In JS, when you step over a return, there's an extra stop location at the return which includes the return value in the variables list:

js.mp4

In Dart, it seems we have a similar extra stop location (it jumps to before the return keyword):

dart.mp4

However, I can't see anything in the VM traffic that indicates the return value so I'm not sure if the reason for this extra stop point was for this reason, or something else.

[bkonyi]

I'm not aware of any way to do that, otherwise it would have already been available alongside the list of other local variables.

We probably have a step location there since we're about to perform the return after evaluating a + b. If we didn't have that location, we'd simply skip past return in a function that returns void.

This does seem like nice behavior, but we'd need to make service changes. It's probably worth filing an issue for this in the SDK, but I don't think it'll be high priority.

[DanTup]

@bkonyi thanks, I've opened dart-lang/sdk#55704