Dart 2 issue in front_end

[natebosch]

~/.pub-cache/hosted/pub.dartlang.org/front_end-0.1.0-alpha.9/lib/src/fasta/source/outline_builder.dart:736:49: Error: A value of type 'dart.core::List<dynamic>' can't be assigned to a variable of type 'dart.core::Iterable<fasta.formal_parameter_builder::FormalParameterBuilder<fasta.type_builder::TypeBuilder>>'.
Try changing the type of the left hand side, or casting the right hand side to 'dart.core::Iterable<fasta.formal_parameter_builder::FormalParameterBuilder<fasta.type_builder::TypeBuilder>>'.
        formals.setRange(count, formals.length, last);

This will prevent running any test in Dart 2 mode.

[peter-ahe-google]

This is a duplicate of #31623.