Show unused variables in different color

[DartBot]

This issue was originally filed by @ahmetaa

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Show unused class and method parameters in different color, possibly gray.
Editor Build: 5845

[kasperl]

Added Area-Editor, Triaged labels.

[stevemessick]

Set owner to @stevemessick.
Removed Type-Defect label.
Added Type-Enhancement label.

[danrubel]

Added this to the Later milestone.

[danrubel]

Issue #3117 has been merged into this issue.

[scheglov]

Could be just warning, as for Java in Eclipse.

Unused variable is a sloppy code, not something what you want to miss.
So, no grey or other pale color.
And IMHO not color at all.

[munificent]

What about cases like this:

    return entrypoint.installDependencies().transform((_) {
      print('Dependencies installed!');
    });

Here, I'm waiting for the future to complete, but it doesn't complete with an interesting value. There's nothing at all wrong with this code, so I wouldn't want to see a warning or color here.

[scheglov]

Hm... Agree.
In Java I never enable warning for unused parameters.

I come here from http://code.google.com/p/dart/issues/detail?id=3117 which speaks about unused variables. This type of warning I'd like to have though.

Best solution could be having just preference page with warnings and specific types of decorations for them. But I'm afraid that my team members will want to kick me for saying this :-)

[clayberg]

Issue #7818 has been merged into this issue.

[clayberg]

Issue #9147 has been merged into this issue.

[stevemessick]

Added NotPlanned label.

[clayberg]

Removed this from the Later milestone.
Added this to the M5 milestone.