tree 2c491a5a7e7df81aae170cb5342cb61b111520be
parent 9ac7bd78550ac5c73b2131a71751a30e6ae967e7
author Paul Berry <paulberry@google.com> 1557179282 +0000
committer commit-bot@chromium.org <commit-bot@chromium.org> 1557179282 +0000

Create a data structure to track the graph of nullability nodes.

The previous design (which stored the graph impicitly in the nodes
themselves) had a memory leak because some nullability nodes are
static, meaning that once a node became connected to one of the static
nodes, it would never be garbage collected.

Change-Id: I9821660198e29ff974ee0afa678851e0418e0527
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/101487
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>