Bump Dart SDK to 1.22.0-dev.10.1.
#7741
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Fixes: flutter#7736 Unblocks flutter#7734 (migration to using `covariant` syntax).
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What's the story on the |
| @@ -143,7 +143,7 @@ class WidgetController { | |||
| /// | |||
| /// * Use [firstState] if you expect to match several states but only want the first. | |||
| /// * Use [stateList] if you expect to match several states and want all of them. | |||
| T state<T extends State>(Finder finder) { | |||
| T state<T extends State>(Finder finder) { // ignore: strong_mode_not_instantiated_bound | |||
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There is a breaking change in the latest dev release to make strong mode be more conservative about guessing default type arguments when code leaves off a type argument. Here, State is defined as
State<T extends StatefulWidget>Previously, strong mode would just guess that you meant State<StatefulWidget> when you wrote State. Writing this explicitly here will fix the error.
This error is primarily aimed at eliminating cases where we simply can't guess a reasonable answer, e.g.
class Foo<T extends Foo<T>> {}
Foo x; // What does Foo mean here?
There is some ongoing discussion as to whether to allow cases like State here where there is an answer we can guess.
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State is marked @optionalTypeArgs. I would hope it would default to the broadest type possible (dynamic, or, in the case of a <T extends Q>, Q).
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Ok, that's good to know. In general that's what we do (that is, fill in with the bound), but we're being a bit more conservative with types used in bounds.
Would you expect to be able to use my example Foo above with no type arguments? And if so what would you expect it to mean?
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I can't wrap my head around your example. I think I'd be ok with the compiler falling over when faced with that type. :-)
My understanding is that this warning is still a work in progress. In any event @bwilkerson and I looked at a proper fix and I got shy since it would likely involve some invasive changes. Maybe @leafpetersen can guide us to the light? (EDIT: he already has! 😊 ) |
| @@ -278,7 +278,7 @@ class IOSDevice extends Device { | |||
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| Future<int> launch = runCommandAndStreamOutput(launchCommand, trace: true); | |||
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| List<Uri> uris = await launch.then((int result) async { | |||
| List<Uri> uris = await launch.then<List<Uri>>((int result) async { | |||
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Is this an inference regression, or an unrelated fix?
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Ah. Good catch. I should have flagged this. Regression. flutter analyze reported:
[error] Missing type arguments for generic method 'then<S>'. (packages/flutter_tools/lib/src/commands/daemon.dart, line 467, col 57)
[error] Missing type arguments for generic method 'then<S>'. (packages/flutter_tools/lib/src/ios/devices.dart, line 281, col 37)
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Is there any chance that this is a holdover from dev.10.0? We had a regression related to async/await, but I can't reproduce this error in either dev.10.1 or bleeding edge.
I'm not testing the actual code, so it's possible there's an issue I'm not seeing, but I have a repro that should be capturing everything relevant and I don't see any issues.
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It was definitely failing flutter analyze w/ dev.10.1 , though interestingly I was not seeing the errors in IntelliJ.
Maybe @danrubel can comment on that disconnect. I haven't had time to follow-up on it...
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Four new |
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Thanks for all the guidance @leafpetersen ! @Hixie : do we have a next-step? It'd be great to land this so you all can start playing with covariants (right @sethladd 😉 ?) Are there any tracking bugs I can add to the ignores to provide more context for future cleanup? (Alternatively, I could link back to this PR I suppose...) |
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Testing |
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Filed dart-lang/sdk#28580 to track the relaxation on the restriction on type bounds. |
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The latest engine version requires Dart SDK 1.22.0-dev.10.1. So, this is currently blocking the engine roll (#7777), which includes fixes for Flutter on Windows. What is the path forward on bumping the Dart SDK? |
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Closing this in favour of #7791. |
Fixes: #7736
Unblocks #7734 (migration to using
covariantsyntax).@Hixie @abarth @tvolkert
FYI @leafpetersen for strong mode suppressions