The #2 most reported Rust annoyance (right after compile speed) is about to shrink. 🦀 Big target directories were the second most common complaint in the 2025 State of Rust survey. One real cause: Cargo has been storing the same crate metadata twice on disk, once in the .rmeta file (produced early, so dependent crates can start compiling sooner) and again inside the final .rlib file. Cargo will soon default to -Zembed-metadata=no on nightly, which stops embedding that duplicate metadata into .rlib files. Real measured numbers, compiling serde and Cargo itself: → Release profile, no debug info: up to 33% smaller target directory → Cargo's own release build: ~300 MiB saved in absolute terms → Dev profile with incremental + debuginfo: a more modest ~5-8%, since debug info and incremental artifacts dominate there anyway Most people won't notice anything except a smaller target directory. The only real edge case: if you link .rlib files manually outside of normal Cargo builds, you may now need to pass the matching .rmeta file explicitly. Nightly only for now, with stabilization planned if the rollout goes smoothly. Opt-out available via CARGO_UNSTABLE_EMBED_METADATA=true if you hit issues. Small on its own, but with survey data showing how many people this genuinely affects. 🔗 blog.rust-lang.org/inside-ru… #RustLang #Cargo #DevTools #OpenSource