Tracking Issue for #138068: Add `Result::map_or_default` and `Option::map_or_default`

[fpervaiz]

Feature gate: #![feature("result_option_map_or_default")]

This is a tracking issue for adding Result::map_or_default() and Option::map_or_default(). Open RFC rust-lang/rfcs#3148

Public API

// core::result

impl<T, E> Result<T, E> {
    pub fn map_or_default<U, F>(self, f: F) -> U
    where
        U: Default,
        F: FnOnce(T) -> U { .. }
}

// core::option

impl<T> Option<T> {
    pub fn map_or_default<U, F>(self, f: F) -> U
    where
        U: Default,
        F: FnOnce(T) -> U { .. }
}

Steps / History

• Implementation: Add Result::map_or_default and Option::map_or_default #141659
• Final comment period (FCP)¹
• Stabilization PR

Unresolved Questions

• None yet.

Footnotes

1. https://std-dev-guide.rust-lang.org/feature-lifecycle/stabilization.html ↩

[tkr-sh]

@fpervaiz The FCP is not done, and we will need multiple months before so

[scovich]

Out of curiosity, what is the status here? Was there an implementation hiccup of some kind, or other controversy?

[tkr-sh]

Hello @scovich !
It's currently in nightly rust: (Option::map_or_default, Result::map_or_default)
This will have to wait multiple months before the FCP and the stabilization. It's the usual process :>

[Rua]

Nothing else came up here, so I assume it's all ok and able to be stabilised now?

[joshtriplett]

Nominating this for libs-api to consider stabilization.

[joshtriplett]

@rfcbot merge libs-api

[rust-rfcbot]

Team member @joshtriplett has proposed to merge this. The next step is review by the rest of the tagged team members:

• @Amanieu
• @BurntSushi
• @dtolnay
• @joshtriplett
• @the8472

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.