12dc24f460
This commit is a response to feedback on the displayed type signatures results, by making generics act stricter. Generics are tightened by making order significant. This means `Vec<Allocator>` now matches only with a true vector of allocators, instead of matching the second type param. It also makes unboxing within generics stricter, so `Result<A, B>` only matches if `B` is in the error type and `A` is in the success type. The top level of the function search is unaffected. Find the discussion on: * <https://rust-lang.zulipchat.com/#narrow/stream/393423-t-rustdoc.2Fmeetings/topic/meeting.202024-07-08/near/449965149> * <https://github.com/rust-lang/rust/pull/124544#issuecomment-2204272265> * <https://rust-lang.zulipchat.com/#narrow/channel/266220-t-rustdoc/topic/deciding.20on.20semantics.20of.20generics.20in.20rustdoc.20search/near/476841363>
19 lines
633 B
Rust
19 lines
633 B
Rust
#![crate_name = "generics_match_ambiguity"]
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pub struct Wrap<T, U = ()>(pub T, pub U);
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pub fn foo(a: Wrap<i32>, b: Wrap<i32, u32>) {}
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pub fn bar(a: Wrap<i32, u32>, b: Wrap<i32>) {}
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pub struct W2<T>(pub T);
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pub struct W3<T, U = ()>(pub T, pub U);
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pub fn baaa(a: W3<i32>, b: W3<i32, u32>) {}
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pub fn baab(a: W3<i32, u32>, b: W3<i32>) {}
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pub fn baac(a: W2<W3<i32>>, b: W3<i32, u32>) {}
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pub fn baad(a: W2<W3<i32, u32>>, b: W3<i32>) {}
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pub fn baae(a: W3<i32>, b: W2<W3<i32, u32>>) {}
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pub fn baaf(a: W3<i32, u32>, b: W2<W3<i32>>) {}
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pub fn baag(a: W2<W3<i32>>, b: W2<W3<i32, u32>>) {}
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pub fn baah(a: W2<W3<i32, u32>>, b: W2<W3<i32>>) {}
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