Do not treat lifetimes from parent items as influencing child items #139075
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compiler-errors approved these changes Mar 28, 2025
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bors added a commit to rust-lang-ci/rust that referenced this pull request Mar 28, 2025
…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#138976 (Explain one-past-the-end pointer in std library) - rust-lang#139052 (Put pin!() tests in the right file.) - rust-lang#139058 (Fix formatting nit in process.rs) - rust-lang#139063 (Fix TAIT & ATPIT feature gating in the presence of anon consts) - rust-lang#139065 (Miri subtree update) - rust-lang#139069 (`io::Take`: avoid new `BorrowedBuf` creation in some case) - rust-lang#139075 (Do not treat lifetimes from parent items as influencing child items) - rust-lang#139079 (tracking autodiff files via triagebot.toml) Failed merges: - rust-lang#139044 (bootstrap: Avoid cloning `change-id` list) r? `@ghost` `@rustbot` modify labels: rollup
rust-timer added a commit to rust-lang-ci/rust that referenced this pull request Mar 29, 2025
Rollup merge of rust-lang#139075 - oli-obk:resolver-item-lifetime, r=compiler-errors Do not treat lifetimes from parent items as influencing child items ```rust struct A; impl Bar<'static> for A { const STATIC: &str = ""; // ^ no future incompat warning } ``` has no future incompat warning, because there is no ambiguity. But ```rust struct C; impl Bar<'_> for C { // ^^ this lifeimte const STATIC: &'static str = { struct B; impl Bar<'static> for B { const STATIC: &str = ""; // causes ^ to emit a future incompat warning } "" }; } ``` had one before this PR, because the impl for `B` (which is just a copy of `A`) thought it was influenced by a lifetime on the impl for `C`. I double checked all other `lifetime_ribs` iterations and all of them do check for `Item` boundaries. This feels very fragile tho, and ~~I think we should do not even be able to see ribs from parent items, but that's a different refactoring that I'd rather not do at the same time as a bugfix~~. EDIT: ah nevermind, this is needed for improving diagnostics like "use of undeclared lifetime" being "can't use generic parameters from outer item" instead. r? `@compiler-errors`
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has no future incompat warning, because there is no ambiguity. But
had one before this PR, because the impl for
B(which is just a copy ofA) thought it was influenced by a lifetime on the impl forC.I double checked all other
lifetime_ribsiterations and all of them do check forItemboundaries. This feels very fragile tho, andI think we should do not even be able to see ribs from parent items, but that's a different refactoring that I'd rather not do at the same time as a bugfix. EDIT: ah nevermind, this is needed for improving diagnostics like "use of undeclared lifetime" being "can't use generic parameters from outer item" instead.r? @compiler-errors