I'm currently following along with https://raytracing.github.io/books/RayTracingInOneWeekend.html but I'm implementing everything in Rust. Here's a excerpt from my vector implementation:
type Scalar = f64; #[derive(Debug, Default, Clone)] pub struct Vector { x: Scalar, y: Scalar, z: Scalar, } impl Vector { fn new(x: Scalar, y: Scalar, z: Scalar) -> Self { Self { x, y, z } } fn x(&self) -> Scalar { self.x } fn y(&self) -> Scalar { self.y } fn z(&self) -> Scalar { self.z } } impl std::ops::Mul<&Vector> for &Vector { type Output = Scalar; fn mul(self, rhs: Self) -> Self::Output { self.x() * rhs.x() + self.y() * rhs.y() + self.z() * rhs.z() } } When I try to compile it, I get the following message:
error[E0308]: method not compatible with trait --> src/point.rs:33:5 | 33 | fn mul(self, rhs: Self) -> Self::Output { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ lifetime mismatch | = note: expected fn pointer `fn(&point::Vector, &point::Vector) -> _` found fn pointer `fn(&point::Vector, &point::Vector) -> _` note: the lifetime `'_` as defined on the impl at 30:20... --> src/point.rs:30:20 | 30 | impl std::ops::Mul<&Vector> for &Vector { | ^ note: ...does not necessarily outlive the lifetime `'_` as defined on the impl at 30:20 --> src/point.rs:30:20 | 30 | impl std::ops::Mul<&Vector> for &Vector { | ^ error: aborting due to previous error For more information about this error, try `rustc --explain E0308`. error: could not compile `raytracing`. However, if I change the Self parameter on the mul function to &Vector, it compiles just fine:
[...] fn mul(self, rhs: &Vector) -> Self::Output { [...] Is this just a case where the lifetime inference fails? If so, why is it failing, since the compiler seems to have inferred everything correctly?
