Flow analysis didn't handle invalid type so non-null promotion would occur on declaration and initialization on erroneous code, leading to warnings about null-aware that is likely valid. For instance
f(Unresolved o) { // Error: Unresolved is unresolved
int? i = o.property;
i?.isEven; // Warning about unnecessary null-aware access
if (i != null) { // Warning about unnecessary null comparison
i.isEven;
}
}
To handle this fully we need to track invalid nullability (if that is even feasible) but for now we change the default to avoid non-null promotion in such cases.
This *does* change the kind cascading errors/warnings that we produce. For instance
f(Unresolved o) { // Error: Unresolved is unresolved
int? i = o.nonNullProperty;
i.isEven; // Error for access on int?
}
but since it probably more likely for code to *not* depend on non-null promotion, this should be less noise for the user.
Change-Id: Ia2bc3505a43b52e5151b93a7fee24e95246b4bbc
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/443320
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Paul Berry <paulberry@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>
Johnni Winther
e6e94f79d2