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

Calculating dependencies ... done!
Dependency resolution took 1.62 s (backtrack: 0/20).

[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     ] app-benchmarks/hyperfine-1.21.0::gentoo  USE="-debug" 23895 KiB

Total: 2 packages (1 new, 1 in new slot), Size of downloads: 229425 KiB