false positives of cascade_invocations when there are implicit downcast assignments

[yyoon]

Here's an example snippet.

class Foo {}

class Bar extends Foo {
  void bar() {}
}

void baz(Foo foo) {
  Bar bar = foo;
  bar.bar();      // This line is reported by cascade_invocations rule
}

In this case, we can't simply change this to Bar bar = foo..bar(); because foo is not of type Bar until it is assigned to bar variable using implicit downcast. The only reasonable way I found to get around this issue is to suppress the warning with an // ignore: cascade_invocations comment, but maybe I missed something.

[a14n]

an other workaround (foo as Bar).bar()

[yyoon]

Yes, that works. Although we have avoid_as turned on as well, so it's not an option for us.

[zoechi]

Is there still a good reason for avoid_as?
I thought that was for performance reasons that are no longer relevant.

update: #34582

[asashour]

The case is not compilable, for line

Bar bar = foo;

A value of type 'Foo' can't be assigned to a variable of type 'Bar'. (Documentation)
Try changing the type of the variable, or casting the right-hand type to 'Bar'.

[bwilkerson]

The original example was written prior to null safety. After null safely there would need to be either an explicit cast or a type test.

I suspect that we can close this issue.

[pq]

I agree. I'm guessing there's a host of issues like this.