e6ac464ff0
This is cleanup work required to start enforcing this with static analysis, as per https://github.com/dart-lang/sdk/issues/53253. Real quick this issue is that this code is unsafe: ```dart void f(Completer<int> c, int? i) { Future<int>.value(i); // Ouch! c.complete(i); // Ouch! } ``` Change-Id: Ia4d83719c425601b24e8ae6e305c88c95cba8b20 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/324640 Auto-Submit: Samuel Rawlins <srawlins@google.com> Commit-Queue: Liam Appelbe <liama@google.com> Reviewed-by: Liam Appelbe <liama@google.com>