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This error doesn't do a good job at all of highlighting the important thing! You can't define an inherent impl on a type parameter. You have to make it the impl of some trait. Here's an example: Tr...
Answer
#4: Post edited
by
r~~
·
2020-09-20T04:35:47Z (about 4 years ago)
Sized is only necessary on A, not AsMutExt
- This error doesn't do a good job at all of highlighting the important thing!
You can't define an inherent `impl` on a type parameter. You have to make it the `impl` of some trait. Here's an example: [Try it online!](https://tio.run/##jZFLa8JAFIX3@RVHCmWCQfqw1o4aiKmLLgTBZQgS46QEklTnEfrA357OTNRqF6V3cbnMnPudkwlXQjaN5EkuEVAs80@2wZcDXfJjyzAd2TmrkJGS4rpUEtGSFVnsYa31eqJ06o6cveMcKGKu5Oxdjl@qinGKwL/EWpTlCL1sKa3yiMnLbXFa9jCnLXIc2bPYR7fl@b@sfGRvHPN/2BwkpgJKM2IUvUSstJq4Wura670JcxVtGM9rRhYJl3lSzHYentlavbqxIyRXqUQIogZ9nd0ER2BThBdviAnU8O@HVMPzVAaRIq9Qnh2aSns36E6wRiKgTUeny/1PZG1RJnlFjsCCSRi3WseoWdqJQnKrvzIkd7bf29534xZW9zLy4LZzIgTjcsV2HVJ70HsDq320fWj7kxubv9Y03w "Rust – Try It Online")- ```rust
- trait A: Sized {
- type B;
- fn f(m: &mut [Self], b: Self::B);
- }
trait AsMutExt<Inner: A>: Sized {- fn f(&mut self, b: Inner::B);
- }
impl<Inner: A, M: AsMut<[Inner]> + Sized> AsMutExt<Inner> for M {- fn f(&mut self, b: Inner::B) {
- A::f(self.as_mut(), b)
- }
- }
- #[derive(PartialEq, Debug)]
- struct C (u64);
- impl A for C {
- type B = u8;
- fn f(m: &mut [Self], b: u8) {
- for c in m {
- c.0 += b as u64;
- }
- }
- }
- fn main() {
- let mut v = vec![C(1), C(2), C(3), C(4)];
- v.f(5);
- assert_eq!(v, [C(6), C(7), C(8), C(9)]);
- }
- ```
- This error doesn't do a good job at all of highlighting the important thing!
- You can't define an inherent `impl` on a type parameter. You have to make it the `impl` of some trait. Here's an example: [Try it online!](https://tio.run/##jZFLa8JAFIX3@RVHCmWGBunT2lEDMXXRhVBwGYLEOCmBJNV5hD7wt6czE7W2i9K7uFxmzvnuyURoqdpWibRQCBkWxQdf49ODKfW@4ZiO3JzXyEnFcF5phXjByzzxsTJ6MzE2pSNv53l7ipxrNXtT46e65oIhDPY8x3AAaVzO3kkO/qLalEeXjznrWOPYnSVB8IsdIH8VmP8Dv5fYChnLiVX0U7k0akKNlLrrnQ1xFq@5KBpOnlOhirScbX088pV@oYknldCZQgSiB7cmsw2M0KWIfjwaJtDDv19OD09TWUSGokZ1cmgr61/iYoIVUgmzdHS83H1HNiuqtKjJAVhyBbutMTEanvXiiFyZr4zItes3rt/SpIM1/Zzc0W5OpeRCLfm2Rxofxjdw2nvXh64/0MT@rbb9Ag "Rust – Try It Online")
- ```rust
- trait A: Sized {
- type B;
- fn f(m: &mut [Self], b: Self::B);
- }
- trait AsMutExt<Inner: A> {
- fn f(&mut self, b: Inner::B);
- }
- impl<Inner: A, M: AsMut<[Inner]>> AsMutExt<Inner> for M {
- fn f(&mut self, b: Inner::B) {
- A::f(self.as_mut(), b)
- }
- }
- #[derive(PartialEq, Debug)]
- struct C (u64);
- impl A for C {
- type B = u8;
- fn f(m: &mut [Self], b: u8) {
- for c in m {
- c.0 += b as u64;
- }
- }
- }
- fn main() {
- let mut v = vec![C(1), C(2), C(3), C(4)];
- v.f(5);
- assert_eq!(v, [C(6), C(7), C(8), C(9)]);
- }
- ```
#3: Post edited
by
wizzwizz4
·
2020-09-20T04:28:13Z (about 4 years ago)
- This error doesn't do a good job at all of highlighting the important thing!
- You can't define an inherent `impl` on a type parameter. You have to make it the `impl` of some trait. Here's an example: [Try it online!](https://tio.run/##jZFLa8JAFIX3@RVHCmWCQfqw1o4aiKmLLgTBZQgS46QEklTnEfrA357OTNRqF6V3cbnMnPudkwlXQjaN5EkuEVAs80@2wZcDXfJjyzAd2TmrkJGS4rpUEtGSFVnsYa31eqJ06o6cveMcKGKu5Oxdjl@qinGKwL/EWpTlCL1sKa3yiMnLbXFa9jCnLXIc2bPYR7fl@b@sfGRvHPN/2BwkpgJKM2IUvUSstJq4Wura670JcxVtGM9rRhYJl3lSzHYentlavbqxIyRXqUQIogZ9nd0ER2BThBdviAnU8O@HVMPzVAaRIq9Qnh2aSns36E6wRiKgTUeny/1PZG1RJnlFjsCCSRi3WseoWdqJQnKrvzIkd7bf29534xZW9zLy4LZzIgTjcsV2HVJ70HsDq320fWj7kxubv9Y03w "Rust – Try It Online")
- ```rust
- trait A: Sized {
- type B;
- fn f(m: &mut [Self], b: Self::B);
- }
- trait AsMutExt<Inner: A>: Sized {
- fn f(&mut self, b: Inner::B);
- }
impl<Inner: A, M: AsMut<[Inner]> + Sized> M {- fn f(&mut self, b: Inner::B) {
- A::f(self.as_mut(), b)
- }
- }
- #[derive(PartialEq, Debug)]
- struct C (u64);
- impl A for C {
- type B = u8;
- fn f(m: &mut [Self], b: u8) {
- for c in m {
- c.0 += b as u64;
- }
- }
- }
- fn main() {
- let mut v = vec![C(1), C(2), C(3), C(4)];
- v.f(5);
- assert_eq!(v, [C(6), C(7), C(8), C(9)]);
- }
- ```
- This error doesn't do a good job at all of highlighting the important thing!
- You can't define an inherent `impl` on a type parameter. You have to make it the `impl` of some trait. Here's an example: [Try it online!](https://tio.run/##jZFLa8JAFIX3@RVHCmWCQfqw1o4aiKmLLgTBZQgS46QEklTnEfrA357OTNRqF6V3cbnMnPudkwlXQjaN5EkuEVAs80@2wZcDXfJjyzAd2TmrkJGS4rpUEtGSFVnsYa31eqJ06o6cveMcKGKu5Oxdjl@qinGKwL/EWpTlCL1sKa3yiMnLbXFa9jCnLXIc2bPYR7fl@b@sfGRvHPN/2BwkpgJKM2IUvUSstJq4Wura670JcxVtGM9rRhYJl3lSzHYentlavbqxIyRXqUQIogZ9nd0ER2BThBdviAnU8O@HVMPzVAaRIq9Qnh2aSns36E6wRiKgTUeny/1PZG1RJnlFjsCCSRi3WseoWdqJQnKrvzIkd7bf29534xZW9zLy4LZzIgTjcsV2HVJ70HsDq320fWj7kxubv9Y03w "Rust – Try It Online")
- ```rust
- trait A: Sized {
- type B;
- fn f(m: &mut [Self], b: Self::B);
- }
- trait AsMutExt<Inner: A>: Sized {
- fn f(&mut self, b: Inner::B);
- }
- impl<Inner: A, M: AsMut<[Inner]> + Sized> AsMutExt<Inner> for M {
- fn f(&mut self, b: Inner::B) {
- A::f(self.as_mut(), b)
- }
- }
- #[derive(PartialEq, Debug)]
- struct C (u64);
- impl A for C {
- type B = u8;
- fn f(m: &mut [Self], b: u8) {
- for c in m {
- c.0 += b as u64;
- }
- }
- }
- fn main() {
- let mut v = vec![C(1), C(2), C(3), C(4)];
- v.f(5);
- assert_eq!(v, [C(6), C(7), C(8), C(9)]);
- }
- ```
#2: Post edited
by
r~~
·
2020-09-14T23:59:47Z (over 4 years ago)
- This error doesn't do a good job at all of highlighting the important thing!
You can't define an inherent `impl` on a type parameter. You have to make it the `impl` of some trait. Here's an example: [Try it online!](https://tio.run/##jZFLa8JAFIX3@RVHCmWCQfqw1o4aiKmLLgTBZQgS46QEklTnEfrA357OTNRqF6V3cbnMnPudkwlXQjaN5EkuEVAs80@2wZcDXfJjyzAd2TmrkJGS4rpUEtGSFVnsYa31eqJ06o6cveMcKGKu5Oxdjl@qinGKwL/EWpTlCL1sKa3yiMnLbXFa9jCnLXIc2bPYR7fl@b@sfGRvHPN/2BwkpgJKM2IUvUSstJq4Wura670JcxVtGM9rRhYJl3lSzHYentlavbqxIyRXqUQIogZ9nd0ER2BThBdviAnU8O@HVMPzVAaRIq9Qnh2aSns36E6wRiKgTUeny/1PZG1RJnlFjsCCSRi3WseoWdqJQnKrvzIkd7bf29534xZW9zLy4LZzIgTjcsV2HVJ70HsDq320fWj7kxubv9Y03w "Rust – Try It Online")
- This error doesn't do a good job at all of highlighting the important thing!
- You can't define an inherent `impl` on a type parameter. You have to make it the `impl` of some trait. Here's an example: [Try it online!](https://tio.run/##jZFLa8JAFIX3@RVHCmWCQfqw1o4aiKmLLgTBZQgS46QEklTnEfrA357OTNRqF6V3cbnMnPudkwlXQjaN5EkuEVAs80@2wZcDXfJjyzAd2TmrkJGS4rpUEtGSFVnsYa31eqJ06o6cveMcKGKu5Oxdjl@qinGKwL/EWpTlCL1sKa3yiMnLbXFa9jCnLXIc2bPYR7fl@b@sfGRvHPN/2BwkpgJKM2IUvUSstJq4Wura670JcxVtGM9rRhYJl3lSzHYentlavbqxIyRXqUQIogZ9nd0ER2BThBdviAnU8O@HVMPzVAaRIq9Qnh2aSns36E6wRiKgTUeny/1PZG1RJnlFjsCCSRi3WseoWdqJQnKrvzIkd7bf29534xZW9zLy4LZzIgTjcsV2HVJ70HsDq320fWj7kxubv9Y03w "Rust – Try It Online")
- ```rust
- trait A: Sized {
- type B;
- fn f(m: &mut [Self], b: Self::B);
- }
- trait AsMutExt<Inner: A>: Sized {
- fn f(&mut self, b: Inner::B);
- }
- impl<Inner: A, M: AsMut<[Inner]> + Sized> M {
- fn f(&mut self, b: Inner::B) {
- A::f(self.as_mut(), b)
- }
- }
- #[derive(PartialEq, Debug)]
- struct C (u64);
- impl A for C {
- type B = u8;
- fn f(m: &mut [Self], b: u8) {
- for c in m {
- c.0 += b as u64;
- }
- }
- }
- fn main() {
- let mut v = vec![C(1), C(2), C(3), C(4)];
- v.f(5);
- assert_eq!(v, [C(6), C(7), C(8), C(9)]);
- }
- ```
#1: Initial revision
by
r~~
·
2020-09-14T23:56:47Z (over 4 years ago)
This error doesn't do a good job at all of highlighting the important thing! You can't define an inherent `impl` on a type parameter. You have to make it the `impl` of some trait. Here's an example: [Try it online!](https://tio.run/##jZFLa8JAFIX3@RVHCmWCQfqw1o4aiKmLLgTBZQgS46QEklTnEfrA357OTNRqF6V3cbnMnPudkwlXQjaN5EkuEVAs80@2wZcDXfJjyzAd2TmrkJGS4rpUEtGSFVnsYa31eqJ06o6cveMcKGKu5Oxdjl@qinGKwL/EWpTlCL1sKa3yiMnLbXFa9jCnLXIc2bPYR7fl@b@sfGRvHPN/2BwkpgJKM2IUvUSstJq4Wura670JcxVtGM9rRhYJl3lSzHYentlavbqxIyRXqUQIogZ9nd0ER2BThBdviAnU8O@HVMPzVAaRIq9Qnh2aSns36E6wRiKgTUeny/1PZG1RJnlFjsCCSRi3WseoWdqJQnKrvzIkd7bf29534xZW9zLy4LZzIgTjcsV2HVJ70HsDq320fWj7kxubv9Y03w "Rust – Try It Online")