Fix capturing duplicated lifetimes via parent in precise_captures (impl use<'...>)
#124104
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| fn good2() -> impl use<'a> Into<<Self as Tr>::Assoc> {} |
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Document that this test is ensuring that Self captures work, even though they refer to the parent's 'a instead of the opaque type's copy
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…iaskrgr Rollup of 3 pull requests Successful merges: - rust-lang#123409 (Implement Modified Condition/Decision Coverage) - rust-lang#124104 (Fix capturing duplicated lifetimes via parent in `precise_captures` (`impl use<'...>`)) - rust-lang#124137 (Match hyphen in multi-revision comment matchers) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup merge of rust-lang#124104 - compiler-errors:parent-generic-use, r=oli-obk Fix capturing duplicated lifetimes via parent in `precise_captures` (`impl use<'...>`) For technical reasons related to the way that `Self` and `T::Assoc` are lowered from HIR -> `rustc_middle::ty`, an opaque may mention in its bounds both the original early-bound lifetime from the parent `impl`/`fn`, *and* the *duplicated* early-bound lifetime on the opaque. This is fine -- and has been fine since `@cjgillot` rewrote the way we handled opaque lifetime captures, and we went further to allow this behavior explicitly in rust-lang#115659. It's worthwhile to read this PR's technical section to recall how this duplication works and when it acts surprisingly. The problem here is that the check that make sure that `impl use<'a, 'b>` lists all of the opaque's captured lifetimes wasn't smart enough to consider both these captured lifetimes and the original lifetimes they're duplicated from to be equal. This PR fixes that. r? oli-obk
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For technical reasons related to the way that
SelfandT::Assocare lowered from HIR ->rustc_middle::ty, an opaque may mention in its bounds both the original early-bound lifetime from the parentimpl/fn, and the duplicated early-bound lifetime on the opaque.This is fine -- and has been fine since @cjgillot rewrote the way we handled opaque lifetime captures, and we went further to allow this behavior explicitly in #115659. It's worthwhile to read this PR's technical section to recall how this duplication works and when it acts surprisingly.
The problem here is that the check that make sure that
impl use<'a, 'b>lists all of the opaque's captured lifetimes wasn't smart enough to consider both these captured lifetimes and the original lifetimes they're duplicated from to be equal. This PR fixes that.r? oli-obk