| commit | 6c5c9d384f1063a860705105a9b28a283e6024b6 | [log] [tgz] |
|---|---|---|
| author | Paul Berry <paulberry@google.com> | Fri Apr 04 12:11:58 2025 -0700 |
| committer | Commit Queue <dart-scoped@luci-project-accounts.iam.gserviceaccount.com> | Fri Apr 04 12:11:58 2025 -0700 |
| tree | bb22c9fb74ce7ba1d4e7a876dafceacdaf5c161f | |
| parent | 6863a4b68ed03f347b09bb22cbd02d5708ad4a37 [diff] |
[sound flow analysis] Implement behaviors for `is` and `as`.
This change updates the flow analysis logic for `is` and `as`
expressions so that when the language feature `sound-flow-analysis` is
enabled, the static type of the operand is compared to the type to the
right of the `is` or `as` keyword. If one of the types is non-nullable
and the other type is `Null`, then the type test is known to fail. For
an `as` expression, this means that the code path following the
expression will be marked as unreachable. For an `is` expression, this
means that any code paths that assume it evaluates to `true` will be
marked as unreachable.
Note that these new behaviors break assumptions made by three
pre-existing flow analysis tests. I was able to adjust one of the
tests ("equalityOp_end does not set reachability for `this`") to
preserve its old behavior. The other two tests became redundant, so I
removed them.
There is no behavioral change if the feature `sound-flow-analysis` is
disabled.
Bug: https://github.com/dart-lang/sdk/issues/60438
Change-Id: Ib3a9e96bd39cf7df4c6c297568763c0f25bc9e39
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/420164
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>
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