One feature considered and ultimately not added to C# 6 was declaration expressions. A declaration expression is a new expression of the form

expression:
     local-variable-type local-variable-declarator

Such an expression resolves to an lvalue for a fresh local variable that is definitely assigned only if the declarator contains an initializer. In addition, we would support fresh variables for out arguments:

argument-value:
     out local-variable-type identifier

We need to precisely define the scope of these variables, and perhaps require that they be initialized at the point of declaration.