<foo< breaks the analyser with big memory hog

[peekpt]

I came from flutter but I think it's dart related.
Procedure:
create new dart file and type
<foo<
try to write something above that line.

Analyser hangs and stops responding

Dart VM version: 2.1.0-edge.5dfe3c8f94c9e880ad56d41316c0830817c96128 (Wed Oct 17 22:26:47 2018 +0000) on "macos_x64"

Affects VScode and Android Studio.

Needs urgent attention because affects code like

Future<List<int>> ...

[scheglov]

This code:

foo
Future<List<int>> bar() {}

produces inconsistent Token stream.

It is parsed as foo Future<List>() {} bar() {}, and the first pair () is synthetic.

However when we look on tokens after Future, it does not point at this () pair, it points at a single token >>, that points at bar.

The result of this is that when Analyzer tries to compute the API signature, it cannot find the end token (the closing parenthesis in the first () pair) and cycles.

[scheglov]

@danrubel @bwilkerson please let me know if this is an expected scanner / parser behavior and is something I need to protect against in Analyzer.

[peekpt]

https://asciinema.org/a/1etc0qaYxX8AKzBNk48Bvp4v3

[scheglov]

https://dart-review.googlesource.com/c/sdk/+/80680

[bwilkerson]

While that CL fixed the hang, it doesn't fix the parser issue, so I'd like to leave this open to track that work.

[iampawan]

This issue still exists when running multiple projects together.

[bwilkerson]

I have no idea why the bot closed this issue.

@danrubel Feel free to close this issue if appropriate.

[jing-pei]

same issues

[stereotype441]

Using a recent version of the analyzer (as of cb17fb6f7b24feeeac54421473d84d9149c2da90), I'm not able to reproduce the hang. #34850 (comment) indicates that the hang has been fixed, but we have an underlying parser issue still. Since the user manifestation of the bug is taken care of, I'm re-classifying as P2.