Promotion and ??

[lrhn]

Was just informed that bool? foo = ...; if (foo ?? false) print(!foo); does not promote foo to non-null in the "then" branch, even though the otherwise equivalent if (foo != null ? foo : false) print(!foo); does.

main() {
 bool? foo = true as dynamic;
 if (foo != null ? foo : false) print(!foo);  // No error here.
 if (foo ?? false) print(!foo);
 //                      ^ error here!
}

Is this deliberate, a flaw in the analysis spec, or a bug?

[leafpetersen]

This is discussed here: #1224 . This issue is largely a duplicate, but I since the discussion in #1224 is not very discoverable, I'll leave this issue open as a better named re-direct to that discussion.

[leafpetersen]

cc @stereotype441

[amir-msh]

As a temporary solution until the Dart team solve it :
print(!foo!);