ToOwned trait is not imported by default

[bollu]

Hey, in the rust nightly, it appears that the ToOwned is not imported by default. I think it should be because it seems to be a core language feature.

[reem]

If this is going to be The Way to go from &str -> String efficiently then it should be in the prelude. cc @alexcrichton

[alexcrichton]

This is currently intentional, and an RFC is required to make changes to the prelude.

As past experiments have shown (RFC) the to_string function is ripe for optimization and is pretty reasonable in performance as-is today. The next route for optimization is to add size hints to the String/Show traits.

Due to the requirement of an RFC to modify the prelude, however, I'm closing this issue.