anchor.diff:          parseCascadeSection('..a/*<E>*/(b)/*<F>*/(c).d/*<G>*/(e)/*<H>*/(f)');
       expect(expression, isNotNull);
       assertNoErrors();
  -    expect(expression, new isInstanceOf<FunctionExpressionInvocation>());
  -    FunctionExpressionInvocation section = expression;
  +    var section = expression as FunctionExpressionInvocation;
       expect(section.function, new isInstanceOf<MethodInvocation>());
       expect(section.typeArguments, isNotNull);
       expect(section.argumentList, isNotNull);
  
positive.code:     Expression expression = parseStringLiteral("'a'");
      expect(expression, isNotNull);
      assertNoErrors();
      expect(expression, new isInstanceOf<SimpleStringLiteral>());
      SimpleStringLiteral literal = expression;
      expect(literal.literal, isNotNull);
      expect(literal.value, "a");
    }
  
negative.code:     Expression expression = parseStringLiteral("r'''  \na'''");
      expect(expression, isNotNull);
      assertNoErrors();
      var literal = expression as SimpleStringLiteral;
      expect(literal.literal, isNotNull);
      expect(literal.value, "a");
    }
  