use lru_cache_macros::lru_cache; use std::ops; #[derive(Clone, Eq, PartialEq, Hash, Debug, Ord, PartialOrd)] struct NoCopyI32(i32); impl ops::Add for NoCopyI32 { type Output = NoCopyI32; fn add(self, rhs: Self) -> Self { NoCopyI32(self.0 + rhs.0) } } impl ops::Sub for NoCopyI32 { type Output = NoCopyI32; fn sub(self, rhs: Self) -> Self { NoCopyI32(self.0 - rhs.0) } } #[test] fn clone_only_type() { #[lru_cache(20)] fn fib(x: NoCopyI32) -> NoCopyI32 { if x <= NoCopyI32(1) { NoCopyI32(1) } else { fib(x.clone() - NoCopyI32(1)) + fib(x - NoCopyI32(2)) } } assert_eq!(fib(NoCopyI32(19)), NoCopyI32(6765)); }