build: make clippy faster by using checking before that operation
build: make clippy faster by using checking before that operation

nodakai/rustup.rs,inejge/rustup.rs,rust-lang/rustup,nodakai/rustup.rs,rust-lang/rustup,rust-lang/rustup,nodakai/rustup.rs,inejge/rustup.rs,inejge/rustup.rs,nodakai/rustup.rs,inejge/rustup.rs,nodakai/rustup.rs,rust-lang/rustup,inejge/rustup.rs,rust-lang/rustup