In Rust this is only guaranteed to be true of "tier 1" targets. Rust also supports many "tier 2" and lower targets where the guarantee is only that the standard

In Rust this is only guaranteed to be true of "tier 1" targets. Rust also supports many "tier 2" and lower targets where the guarantee is only that the standard library will build (not that it actually works) and even then on some platforms only the core is supported.