dev-lang/rust calls `eselect rust update --if-unset` but the eselect-rust dependency is listed as a PDEPEND, so it is installed after rust has already called this function as both eselect-rust and cargo are in pdepend this can also cause cargo to fail if portage chooses to install cargo before eslect-rust
eselect-rust is now in RDEPEND, so this issue should no longer occur.