090b17fe99
From the times where some of the type arguments should have been reported as warnings, the procedure was run twice in two different modes, in order to report some issues as errors and some as warnings. This CL is a cleanup that invokes the procedure once. Additionally, a refactoring of the return value discipline is made: it always returns a list and never returns null. An empty list is returned if there are no issues. Change-Id: Id497216bf51f49c86517cf16a52f03da5b65b1fd Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/180570 Reviewed-by: Johnni Winther <johnniwinther@google.com> Commit-Queue: Dmitry Stefantsov <dmitryas@google.com>