[DevCompiler] Optional named parameter ignored?

[cedx]

• Dart SDK Version: 2.0.0 (Fri Aug 3 10:53:23 2018 +0200) on "windows_x64"
• build_runner: 0.10.0, build_test: 0.10.3, build_web_compilers: 0.4.1, test: 1.3.0
• OS: Windows 10 (64-bit)
• Test browser: Chrome 68
• Any other packages or constraints: json_annotation: 1.0.0, json_serializable: 1.0.1.

I have a project (https://github.com/cedx/lcov.dart) whose tests give different results when run by dart2js and the dev compiler:
dart-lang/build#1724

A FunctionData#toString({bool asDefinition = false}) method is called two times: with asDefinition = true and asDefinition = false (see: https://github.com/cedx/lcov.dart/blob/master/lib/src/function.dart#L33).

When the tests use the dev compiler, it looks like the optional named parameter asDefinition is ignored: its value always seems to be false.

[matanlurey]

Duplicate of #33876

I believe it is fixed at HEAD but not in a release yet.