commit fffe5ce6ec59095ab632d7ab1c280b74cf9efd6c
author Nate Biggs <natebiggs@google.com> Sat Jul 09 01:58:49 2022 +0000
committer Commit Bot <commit-bot@chromium.org> Sat Jul 09 01:58:49 2022 +0000
tree 6695104cea8521fb5e94f4135082b6486831b5c5
parent 9832e68fefd7cdcaca5782741a3dcd69dcf70807

[dart2js] Promote variables after as statements.

Resolves issue where some programs could not be compiled with dart2js and --enabled-asserts flag. The following assert was failing:
https://github.com/dart-lang/sdk/blob/main/pkg/compiler/lib/src/ir/static_type.dart#L987

This assert checks that the promoted static type that Dart2JS calculates for variables is a subtype of the promoted type calculated by the CFE. This was not true in some cases.

The cause of this discrepancy was that `as` expressions were not properly promoting casted variables. For example:


int func() {
  dynamic x = 3.0;
  x as double;
  return x.asInt();
}


The cast on the second line of the function should promote the type of `x` through the rest of the function and `asInt()` should not be a dynamic invocation.

Change-Id: Iea2508627fb6b3f0cdde785624a00aa2d22d75de
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/250860
Reviewed-by: Joshua Litt <joshualitt@google.com>
Reviewed-by: Mayank Patke <fishythefish@google.com>
Commit-Queue: Nate Biggs <natebiggs@google.com>