The topic "Restrictions on Using var in the Parameter List" proposes to evaluate if some lambda expressions does compile or not.
At line 4, the expression "var w -> 99" does not compile. But the book says that it is "because parentheses, (), are required when using the parameter name.".
I disagree with the ending, as parameter names are always mandatory. A better explanation would be "because parentheses, (), are required when using the parameter **type**.".
Thanks for your attention!