Trait is not implemented for array

[Lukasz2891]

Related Component

compiler

Problem

library;

pub trait ArrWrap<T> {
    fn _len(self) -> u64;
    fn _get(self, i: u64) -> T;
}

impl<T> ArrWrap<T> for [T; 1] {
    fn _len(self) -> u64 {
        1
    }

    fn _get(self, i: u64) -> T {
        self[i]
    }
}

pub trait ToVec {
    type V;

    fn to_vec(self) -> Vec<Self::V>;
}

impl<T, U> ToVec for T
where
    T: ArrWrap<U>,
{
    type V = U;

    fn to_vec(self) -> Vec<U> {
        let mut result = Vec::new();
        let mut i = 0;
        while (i < self._len()) {
            result.push(self._get(i));
            i += 1;
        }

        result
    }
}

contract;

use to_vec::*;

configurable {
    TEST: [b256; 1] = ["0x0000000000000000000000008BB8F32Df04c8b654987DAaeD53D6B6091e3B774"],
}

fn xxx() {
    let _: Vec<b256> = TEST.to_vec();
}

causes

fn xxx() {
    let _: Vec<b256> = TEST.to_vec();
                           ^^^^^^ Trait "ArrWrap<U>" is not implemented for type "[b256; 1]".
}

Steps

Use the code as above

Possible Solution(s)

Remove generic parameters ;)

Notes

No response

Installed components

[components]
fuel-core = "0.37.1"
forc = "0.65.2"

[IGI-111]

Here's as minimal an example as I can make it:

script;

pub trait Foo<T> {
    fn foo(a: T);
}

impl<T> Foo<T> for [T; 1] {
    fn foo(a: T) {}
}

pub trait Bar {
    fn bar(self);
}

impl<T> Bar for T
where
    T: Foo<T>,
{
    fn bar(self) {}
}

fn main() {
    let a: [b256; 1] = [0x0000000000000000000000008BB8F32Df04c8b654987DAaeD53D6B6091e3B774];
    a.bar();
}

The fact that Foo<T> is generic seems to be required to trigger the error. Even with the trait constraint a non generic Foo compiles fine.