Before
      
new TextFormField(
  initialValue: 'Hello World',
  controller: _myTextEditingController,
);
      

      
After
      
new TextFormField(
  controller: _myTextEditingController ..text = 'Hello World',
)
// Or more typically:
_myTextEditingController = new TextEditingController(
  text: 'Hello World',
);
new TextFormField(
  controller: _myTextEditingController,
);

#15303 updated the showDialog function to take a builder and deprecated the widget parameter.

    
      
Before
      
showDialog(context: context, child: new Text('hello'))
      

      
After
      
showDialog(context: context, builder: (BuildContext context) => new Text('hello'))