anchor.diff:  void f([int i]) {}
   ''');
   
  -    assertConstraint([ConstraintVariable.always],
  -        decoratedTypeAnnotation('int').node.nullable);
  +    assertConnection(
  +        NullabilityNode.always, decoratedTypeAnnotation('int').node);
     }
   
     test_functionDeclaration_parameter_positionalOptional_no_default_assume_required() async {
  
positive.code: void f({int i = null}) {}
  ''');
  
      assertConstraint([ConstraintVariable.always],
          decoratedTypeAnnotation('int').node.nullable);
    }
  
    test_functionDeclaration_parameter_named_no_default_assume_nullable() async {
  
negative.code: }
  ''');
  
      assertConnection(decoratedTypeAnnotation('int/*3*/').node,
          decoratedTypeAnnotation('int/*1*/').node);
      assertNullCheck(checkExpression('c/*check*/'),
          decoratedTypeAnnotation('C<int/*3*/>/*4*/').node,
          contextNode: decoratedTypeAnnotation('C<int/*1*/>/*2*/').node);
  