class tear-off with extra parameters

While pattern matching has been implemented in the dart language what about using them for function and class tear-off

```dart
class DefaultError {
final Object error;
final StackTrace stackTrace;
final void Function() refresh;

const DefaultError(this.error, this.stackTrace, {required this.refresh});
}

void throwError(void Function(Object error, StackTrace stackTrace) callback) {}

void main(List args) {
// Current
throwError((error, stackTrace) {
DefaultError("error", StackTrace.current, refresh: () {});
});

// Suggestion
throwError(DefaultError.new(refresh: () {}));
}
```
### The idea here is that
```
throwError(DefaultError.new(refresh: () {}));
```
by Passing the extra parameters after the ".new" or after function tear-off

Start with the proposal and its two Dart examples in issue #3208; compare the current callback form with the suggested tear-off syntax and identify the extra-parameter semantics that require specification. Done would require a decided language design and corresponding specification work, but the issue names no files or tests.

Written by the indexing model from the issue text.