Trait Functions With the Same Name Get Disambiguated Arbitrarily #6381

IGI-111 · 2024-08-07T09:11:26Z

CS-FSSA-015

A type can implement two different traits that define the same function. A UFCS-style call syntax is then
needed to explicitly disambiguate because calls like x.foo() will raise a compiler error.
Such an error, however, is not raised if the type is wrapped in a generic struct that has two generic impl
blocks, one bound to the first trait, one to the other, as in the following code snippet:

script;
trait Cat {
 fn speak(self) -> u64;
}
trait Dog {
 fn speak(self) -> u64;
}
struct S<T> {
 x: T,
}
impl<T> S<T>
where
 T: Cat,
{
 fn foo(self) -> u64 {
 self.x.speak()
 }
}
impl<T> S<T>
where
 T: Dog,
{
 fn foo(self) -> u64 {
 self.x.speak()
 }
}
impl Dog for u64 {
 fn speak(self) -> u64 {
 log("2");
 2
 }
}
impl Cat for u64 {
 fn speak(self) -> u64 {
 log("1");
 1
 }
}
fn main() {
 let s = S::<u64> { x: 1 };
 s.foo();
}

The compilation succeeds and the execution output shows that it is the first generic impl (the one bound
to Cat) that prevails.
To the contrary, Rust refuses the compilation of an analogous snippet.

While inserting trait implementations into the trait map we now compare the implementing type_id without matching UnkownGenerics trait constraints. Matching the trait constraints was causing a missing error. Fixes #6381

## Description While inserting trait implementations into the trait map we now compare the implementing type_id without matching UnkownGenerics trait constraints. Matching the trait constraints was causing a missing error. Fixes #6381 ## Checklist - [ ] I have linked to any relevant issues. - [x] I have commented my code, particularly in hard-to-understand areas. - [ ] I have updated the documentation where relevant (API docs, the reference, and the Sway book). - [ ] If my change requires substantial documentation changes, I have [requested support from the DevRel team](https://github.com/FuelLabs/devrel-requests/issues/new/choose) - [x] I have added tests that prove my fix is effective or that my feature works. - [x] I have added (or requested a maintainer to add) the necessary `Breaking*` or `New Feature` labels where relevant. - [x] I have done my best to ensure that my PR adheres to [the Fuel Labs Code Review Standards](https://github.com/FuelLabs/rfcs/blob/master/text/code-standards/external-contributors.md). - [x] I have requested a review from the relevant team or maintainers. Co-authored-by: IGI-111 <[email protected]>

IGI-111 added bug Something isn't working P: medium audit-report Related to the audit report labels Aug 7, 2024

IGI-111 assigned jjcnn Aug 7, 2024

esdrubal mentioned this issue Sep 3, 2024

Fixes impl self duplicated missing error. #6493

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esdrubal self-assigned this Sep 3, 2024

esdrubal closed this as completed in #6493 Sep 3, 2024

IGI-111 reopened this Feb 17, 2025

IGI-111 linked a pull request Feb 17, 2025 that will close this issue

find_method_for_type improvements #6744

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linear bot closed this as completed Feb 17, 2025

IGI-111 reopened this Feb 17, 2025

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Trait Functions With the Same Name Get Disambiguated Arbitrarily #6381

Trait Functions With the Same Name Get Disambiguated Arbitrarily #6381

IGI-111 commented Aug 7, 2024

Trait Functions With the Same Name Get Disambiguated Arbitrarily #6381

Trait Functions With the Same Name Get Disambiguated Arbitrarily #6381

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IGI-111 commented Aug 7, 2024