commit 47abd96c5b8e3c6af3c99b608978f8dee0f56a84
author Alexander Markov <alexmarkov@google.com> Thu Jun 15 00:34:18 2023 +0000
committer Commit Queue <dart-scoped@luci-project-accounts.iam.gserviceaccount.com> Thu Jun 15 00:34:18 2023 +0000
tree e64810d96444d4b8765b68afbb63be17ba1e03af
parent c7b288492aae99a890e202d2d2807a7dc35ca14b

Reland "[vm] Fix CompileType::CanBeFuture()"

This is a reland of commit 6f4bed30ccc022581e147f769bcd88042322a158

Original change's description:
> [vm] Fix CompileType::CanBeFuture()
>
> In certain cases compiler can omit a type check in 'await e' if it can
> prove that expression 'e' cannot be evaluated to Future.
>
> Previously, if actual type of 'e' is unknown, CompileType::CanBeFuture()
> tested if static type of 'e' is a subtype of Future.
>
> This is not correct, as static type could have a subtype which is also
> a subtype of Future, but static type itself is not a subtype of Future:
>
> class A {}
> class B implements A, Future<A> {}
>
> A e = confuse(B()); // 'e' is B, but has a static type A.
> await e;            // A is not a subtype of Future, but 'e' is Future
>                     // and should be awaited.
>

TEST=language/async/await_flatten_test
Fixes https://github.com/dart-lang/sdk/issues/52585

Change-Id: I37add9021261c95dee5930e031187868e821c161
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/309481
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>