These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.63 s (backtrack: 0/20).

[ebuild  N     ] dev-libs/jemalloc-5.4.0-r2:0/2::gentoo  USE="stats -debug -lazy-lock -prof -xmalloc" 893 KiB
[ebuild  NS    ] dev-lang/rust-bin-1.99.0:1.99.0::gentoo [1.94.0:1.94.0::gentoo] USE="clippy rustfmt (-big-endian) -doc* (-prefix) -rust-analyzer -rust-src -verify-sig" CPU_FLAGS_X86="sse2" LLVM_SLOT="(23%*) (-21%*)" 205530 KiB
[ebuild  N     ] dev-util/ruff-0.16.7::gentoo  USE="-debug" 41623 KiB

Total: 3 packages (2 new, 1 in new slot), Size of downloads: 248045 KiB