tree 79e6a2e3806b11cd237c16226cfbba49f8a1c4a2
parent c41e9ae0e8db215eb0b307d0a9bb73b3137daa54
author Paul Berry <paulberry@google.com> 1560190290 +0000
committer commit-bot@chromium.org <commit-bot@chromium.org> 1560190290 +0000

Migration: Clean up handling of LUB and substitution nodes.

Previously we created artifical edges from a LUB node's components to
the LUB node; now the nullability propagation algorithm understands
how to propagate nullability downstream through LUB and substitution
nodes, so no artificial edges are needed.

Change-Id: Ib2fef14c3dcd58a013ad8e057fd55597a1deb4fc
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/105402
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>