Ignore variables named `_`, `__`, ... even when `implicit-dynamic:false`

[zoechi]

These names are usually used for unused parameters.

In Polymer apps I have a lot of methods where a specific signature is expected by Polymer but the parameters passed by default are often not relevant:

  @reflectable
  void searchStringChanged(_, [__]) {
    if (dataView == null) {
      return;
    }
    updateFilter();
  }

adding dynamic everywhere is cumbersome for something that should communicate that it is unused

  void searchStringChanged(dynamic _, [dynamic __]) {

[srawlins]

Implicit-dynamic: false is dead. Closing as stale.