[regression] type inference on parse() #73242
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Mark-Simulacrum
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There were roughly ~15-20 crates that failed in the crater run due to this, mostly in tests. I'm not sure whether we think that's sufficient reasoning to drop the impl, I get that it can be useful... cc @rust-lang/libs (and relabeling as this is not an inference regression) |
Mark-Simulacrum
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Can we add Being able to easily compare a socketaddr to a string seems pretty valuable for testing, I'd rather see we make it easier than require the turbofish. #72239 for the PR that added these impls |
I’m not in favor since this would blur the difference between "this string does not parse as a valid socket address" v.s. "it does, but one not equal to that one". Code that doesn’t care about that difference can already use |
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#72239 mostly cared about PartialOrd and Ord impls (as you can tell from the PR title). Unlike PartialEq, none existed before on SocketAddr so they won't be problematic. I think the PR included new PartialEq impls only in support of heterogeneous PartialOrd (see #72239 (comment)) which was ultimately removed from the PR anyway. I opened #73304 to revert the new PartialEq impls, leaving the PartialOrd and Ord impls from #72239. |
Revert heterogeneous SocketAddr PartialEq impls Originally added in rust-lang#72239. These lead to inference regressions (mostly in tests) in code that looks like: ```rust let socket = SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 8080); assert_eq!(socket, "127.0.0.1:8080".parse().unwrap()); ``` That compiles as of stable 1.44.0 but fails in beta with: ```console error[E0284]: type annotations needed --> src/main.rs:3:41 | 3 | assert_eq!(socket, "127.0.0.1:8080".parse().unwrap()); | ^^^^^ cannot infer type for type parameter `F` declared on the associated function `parse` | = note: cannot satisfy `<_ as std::str::FromStr>::Err == _` help: consider specifying the type argument in the method call | 3 | assert_eq!(socket, "127.0.0.1:8080".parse::<F>().unwrap()); | ``` Closes rust-lang#73242.
Revert heterogeneous SocketAddr PartialEq impls Originally added in rust-lang#72239. These lead to inference regressions (mostly in tests) in code that looks like: ```rust let socket = SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 8080); assert_eq!(socket, "127.0.0.1:8080".parse().unwrap()); ``` That compiles as of stable 1.44.0 but fails in beta with: ```console error[E0284]: type annotations needed --> src/main.rs:3:41 | 3 | assert_eq!(socket, "127.0.0.1:8080".parse().unwrap()); | ^^^^^ cannot infer type for type parameter `F` declared on the associated function `parse` | = note: cannot satisfy `<_ as std::str::FromStr>::Err == _` help: consider specifying the type argument in the method call | 3 | assert_eq!(socket, "127.0.0.1:8080".parse::<F>().unwrap()); | ``` Closes rust-lang#73242.
Revert heterogeneous SocketAddr PartialEq impls Originally added in rust-lang#72239. These lead to inference regressions (mostly in tests) in code that looks like: ```rust let socket = SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 8080); assert_eq!(socket, "127.0.0.1:8080".parse().unwrap()); ``` That compiles as of stable 1.44.0 but fails in beta with: ```console error[E0284]: type annotations needed --> src/main.rs:3:41 | 3 | assert_eq!(socket, "127.0.0.1:8080".parse().unwrap()); | ^^^^^ cannot infer type for type parameter `F` declared on the associated function `parse` | = note: cannot satisfy `<_ as std::str::FromStr>::Err == _` help: consider specifying the type argument in the method call | 3 | assert_eq!(socket, "127.0.0.1:8080".parse::<F>().unwrap()); | ``` Closes rust-lang#73242.
https://play.rust-lang.org/?version=beta&mode=debug&edition=2018&gist=cbe4ae71cf9d88e5c0fdf6d06af3502e as a minimal example.
Unclear whether this is a new trait impl or some regression elsewhere.
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