Will using 'var' affect performance?

Question

Earlier I asked a question about why I see so many examples use the varkeyword and got the answer that while it is only necessary for anonymous types, that it is used noneth

Answer 1

As Joel says, the compiler works out at compile-time what type var should be, effectively it's just a trick the compiler performs to save keystrokes, so for example

var s = "hi";

gets replaced by

string s = "hi";

by the compiler before any IL is generated. The Generated IL will be exactly the same as if you'd typed string.