[daxelrod]

> constructors should be as safe as they can be, which means no allocations, partial or not.

Can you expand upon what you mean by "safe" here?

If you mean "unable to fail", I vehemently disagree. Constructors should validate what is passed into them and fail if that is invalid. The alternative is to construct a zombie object that can't actually be used. Objects like this subvert the type system and lead to lots of unnecessary "if object.is_valid()" checks all over code that uses them.

[userulluipeste]

"safe" like nullifying pointers and dummy-initialization for objects. This kind of initialization has a small footprint on performance, but it was made optional nevertheless, due to language's performance aims (you can skip them if you don't need that). You can make a little bit more complex operations in constructors that involve data validation, but it should only default to blank initialization if something doesn't pass the checks. The initialization that can fail (and the failure must be taken in account) should be done outside constructors. If an object is or isn't considered valid after a dummy initialization is a design decision, and likewise an adjustment in design can avoid excessive "if (object.is_valid())" kind of checks.