Published packages are missing a dev.64.0 SDK constraint but not using new

[CaiJingLong]

flutter doctor -v
[✓] Flutter (Channel dev, v0.5.7, on Mac OS X 10.12.6 16G29, locale zh-Hans-CN)
• Flutter version 0.5.7 at /Users/cai/fluttersdk/flutter
• Framework revision 66091f9696 (4 weeks ago), 2018-07-09 12:52:41 -0700
• Engine revision 6fe748490d
• Dart version 2.0.0-dev.63.0.flutter-4c9689c1d2

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I'm a flutter developer.
I use the flutter packages pub run build_runner build in cli.
The I get a error:

NoSuchMethodError: Attempted to use type 'Set' as a function. Since types do not define a method 'call', this is not possible. Did you intend to call the Set constructor and forget the 'new' operator?
Receiver: Set
Tried calling: Set()

I know that the --preview-dart-2 parameter should be added.

Where should I add this parameter to?

$ which pub
/Users/cai/fluttersdk/flutter/bin/cache/dart-sdk/bin/pub

$which dart
/Users/cai/fluttersdk/flutter/bin/cache/dart-sdk/bin/dart

$which flutter
/Users/cai/fluttersdk/flutter/bin/flutter

Or should I ask this question in flutter?

[eernstg]

This would be a tool version problem: the dart vm version 2.0.0-dev.63.0 complains as described but 2.0.0-dev.64.0 supports omitting new. So when the newer versions of various tools reach Flutter, the issue should go away, and at this point you can include new as a work-around.

[natebosch]

This was my mistake, when I dropped new I failed to update the minimum SDK constraint to one that had a Dart 2 VM by default, and flutter users today have a VM which is Dart 1 by default.

My plan is:

• Cut a branch from the commit before I dropped new.
• Update pubspecs to a +1 release from whatever versions are publish today and publish - everyone on and older SDK should resolve to these
• Go back to master and bump minimum SDK constraints and publish a +2 for everything so that we're back to the code we expect everyone to be on where possible