tree 421099d599143e5208619d91b972ce80a7578e6c
parent 622d54c20900966b3eda031578885e79cd4f3fcc
author Johnni Winther <johnniwinther@google.com> 1612943512 +0000
committer commit-bot@chromium.org <commit-bot@chromium.org> 1612943512 +0000

Reland "[kernel] Ensure that visitors don't implicitly returns `null`"

This is in preparation to migrate package:kernel to null safety.
For the visitor interfaces to support non-nullable return types, the
implementations must avoid using `null` as return value in its base case.

TEST=Refactoring

Change-Id: Ie8fa5d41b99850d9e4abb59634c72920c64128d9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/183691
Reviewed-by: Jens Johansen <jensj@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>