4 ms·

I think cpp does this too

• estebank 4y ago
  It indeed does. The only difference is that Rust has traits (similar to C++'s concepts) which require explicit mention of what interface the type parameters have inside the function, whereas C++'s templates will have a compile error after instantiation if you passed something that didn't meet the expected contract. This is closer to Rust's macros in operation. Given fn foo<T>(a: T, b: T) -> T { a + b } The compiler will complain that you should have been explicit on how T is going to be used: error[E0369]: cannot add `T` to `T` --> src/lib.rs:1:32 | 1 | fn foo<T>(a: T, b: T) -> T { a + b } | - ^ - T | | | T | help: consider restricting type parameter `T` | 1 | fn foo<T: Add<Output = T>>(a: T, b: T) -> T { a + b } | +++++++++++++++++ whereas in C++ this would have been accepted until you called foo with two things that couldn't be added together, like a Rust macro[1]. [1]: https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=1c227b5a1c15675c1217248329d15f4b https://play.rust-lang.org/?version=nightly&mode=debug&editi...