dart2js: bad codegen for native method with optional parameter

[rakudrama]

To repro:
./tools/test.py -m release -c dart2js -r drt -v client/dom/IndexedDB3Test

client/dom/IndexedDB3Test and client/dom/IndexedDB4Test fail for the same reason

Diagnosis:

The dart:dom library contains this definition of 'continueFunction'

class _IDBCursorJs extends _DOMTypeJs implements IDBCursor native "*IDBCursor" {
  ...
  void continueFunction([key = null]) native '''
        if (key == null) return this'continue';
        return this'continue';
      ''';
}

The test calls cursor.continueFunction()
The call fails with Uncaught TypeError: Object #<IDBCursorWithValue> has no method 'continueFunction'

Looking at the generated code, continueFunction$1 has the correct body, but continueFunction$0 is incorrect.

$.dynamicFunction('continueFunction$1').IDBCursor = function(key) {
          if (key == null) return this'continue';
        return this'continue';
      ;
};
$.dynamicFunction('continueFunction$0').IDBCursor = function() {
  return this.continueFunction();
};

[rakudrama]

Changed the title to: "dart2js: bad codegen for native method with optional parameter".

[DartBot]

This comment was originally written by [email protected]

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CL under review: https://chromiumcodereview.appspot.com/10202018/

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Added Started label.

[DartBot]

This comment was originally written by [email protected]

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Added Fixed label.