3 ms·

But that's runtime expensive, or else very restrictive on the compiler. Bad data should fail fast and null is good at doing that.

• pjmlp 4y ago
  It is done at compile time. For example in C#, you would get something like "Use of unassigned local variable xyz". If the performance cost of initilizing the variable is such an unberable cost, there is [SkipLocalsInit].
  • LorenPechtel 4y ago
    Which works in *most* cases. I forget the details but I do recall running into a case where it was griping erroneously (it couldn't reach the use without having reached the initialization) so I gave it a harmless initial value--and it turned around and complained (correctly) that the assignment would never be used. I insist on removing all such warnings so I ended up restructuring the code so the compiler wouldn't get confused. (Fundamentally, this was a case of a child operation that *might* be needed. It could have been rewritten polymorphically but that would have involved a fair amount of refactoring.)
    • pjmlp 4y ago
      Declare the variable closer to its definition point. Also such kind of situations are usually a sign that code blocks should be moved into a separate function.