Why can't an out parameter have a default value?

Question

Currently when trying to do something in a method that takes an out parameter, I need to assign the value of the out parameter in the method body, e.g.

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Answer 1

Default values are available for parameters passed by value. The parameter is still passed to the function but if the code omits the parameter, the compiler supplies the missing value.

Your proposed feature is quite different. Instead of the caller omitting to pass the value, you propose to allow the implementer of the function to omit setting the value. So, this is a quite different feature. Why was it not implemented? Here are some possible reasons:

1. Nobody thought to implement this feature.
2. The designers considered the feature and rejected it as not useful enough to be worth the cost of implementing.
3. The designers considered the feature and rejected it as being confusing because it uses similar syntax to default value parameters, but has a quite different meaning.