In-place initialization

Initializing values in-place without copying them. This eliminates unnecessary copies and allows for self-referential datastructures.

Range of use cases

TODO: Cover the range of use cases like

• Pinned vs unpinned
• Constructor functions
• Fallible

Approaches

• Init expressions
• Out pointers
• Placing
• Guaranteed value emplacement

Potential design axioms

TODO: Add more or remove.

• Support abstraction through function boundaries

Resources

#t-lang/in-place-init

In-place initialization - Rust Project Goals, Fall 2025

• Design meeting 2025-07-30: In-place initialization - HackMD

#t-lang/in-place-init > in-place initialization: RfL design wishes - rust-lang - Zulip