0b9060ec1d
There were no checks for missing source or source position, which caused flaky crashes while running test mirrors/mirrors_reader_test. Change-Id: I73497414ebe7b030ba308851038e0ef9e133aa48 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/100781 Reviewed-by: Ben Konyi <bkonyi@google.com> Commit-Queue: Alexander Markov <alexmarkov@google.com>