Engine roll is blocked by warning from transitive dep source_span #66132
Description
../../cache/.pub-cache/hosted/pub.dartlang.org/source_span-1.8.0-nullsafety/lib/src/highlighter.dart:327:17: Warning: Operand of null-aware operation '!' has type '_Highlight' which excludes null.
- '_Highlight' is from 'package:source_span/src/highlighter.dart' ('../../cache/.pub-cache/hosted/pub.dartlang.org/source_span-1.8.0-nullsafety/lib/src/highlighter.dart').
highlight!.isPrimary ? _primaryColor : _secondaryColor;
This is blocking the engine roller and the Flutter repo no longer has clean analysis. There was a work around committed that hasn't been published yet: https://www.google.com/url?sa=j&url=https%3A%2F%2Fgithub.com%2Fdart-lang%2Fsource_span%2Fpull%2F59&uct=1596224968&usg=CwlxcZOEnRpg06Yh_b2srZmah5w.&source=chat