I agree that doing that type of inference would be convenient - I deal with a lot of nested generics like that on daily basis. But this is just syntactic sugar

I agree that doing that type of inference would be convenient - I deal with a lot of nested generics like that on daily basis. But this is just syntactic sugar, and the var keyword already takes care of the left-hand operand in this equation. Generic functions also do a reasonably good job of type inference under this set of circumstances, although I've found that generic delegates and lambdas not so much.