Note about object lifetime defaults in does not live long enough error #117835
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This is a aspect of Rust that frequently trips up people who are not aware of it yet. This diagnostic attempts to explain what's happening and why the lifetime constraint, that was never mentioned in the source, arose.
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cc #116765 |
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Interesting approach. I didn't look too closely at the actual logic in the object lifetime default "manual" elaboration, namely I didn't try to think of places where it would provide false-positives. But given the pain of cases where this fails, I'd opt to land this now and wait until folks find places where the diagnostic is wrong 😃 r? compiler-errors @bors r+ |
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@bors rollup |
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…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#117327 (Add documentation for some queries) - rust-lang#117835 (Note about object lifetime defaults in does not live long enough error) - rust-lang#117851 (Uplift `InferConst` to `rustc_type_ir`) - rust-lang#117973 (test: Add test for async-move in 2015 Rust proc macro) - rust-lang#117992 (Don't require intercrate mode for negative coherence) - rust-lang#118010 (Typeck break expr even if break is illegal) - rust-lang#118026 (Don't consider regions in `deref_into_dyn_supertrait` lint) - rust-lang#118089 (intercrate_ambiguity_causes: handle self ty infer + reservation impls) r? `@ghost` `@rustbot` modify labels: rollup
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…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#117327 (Add documentation for some queries) - rust-lang#117835 (Note about object lifetime defaults in does not live long enough error) - rust-lang#117851 (Uplift `InferConst` to `rustc_type_ir`) - rust-lang#117973 (test: Add test for async-move in 2015 Rust proc macro) - rust-lang#117992 (Don't require intercrate mode for negative coherence) - rust-lang#118010 (Typeck break expr even if break is illegal) - rust-lang#118026 (Don't consider regions in `deref_into_dyn_supertrait` lint) - rust-lang#118089 (intercrate_ambiguity_causes: handle self ty infer + reservation impls) r? `@ghost` `@rustbot` modify labels: rollup
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…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#117327 (Add documentation for some queries) - rust-lang#117835 (Note about object lifetime defaults in does not live long enough error) - rust-lang#117851 (Uplift `InferConst` to `rustc_type_ir`) - rust-lang#117973 (test: Add test for async-move in 2015 Rust proc macro) - rust-lang#117992 (Don't require intercrate mode for negative coherence) - rust-lang#118010 (Typeck break expr even if break is illegal) - rust-lang#118026 (Don't consider regions in `deref_into_dyn_supertrait` lint) - rust-lang#118089 (intercrate_ambiguity_causes: handle self ty infer + reservation impls) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup merge of rust-lang#117835 - Nilstrieb:note-object-lifetime-defaults, r=compiler-errors Note about object lifetime defaults in does not live long enough error This is a aspect of Rust that frequently trips up people who are not aware of it yet. This diagnostic attempts to explain what's happening and why the lifetime constraint, that was never mentioned in the source, arose. The implementation feels a bit questionable, I'm not sure whether there are better ways to do this. There probably are. fixes rust-lang#117835 r? types
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This is a aspect of Rust that frequently trips up people who are not aware of it yet. This diagnostic attempts to explain what's happening and why the lifetime constraint, that was never mentioned in the source, arose.
The implementation feels a bit questionable, I'm not sure whether there are better ways to do this. There probably are.
fixes #117835
r? types