Implement the precise analysis pass for lint disjoint_capture_drop_reorder
#81912
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| @@ -642,6 +650,279 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { | |||
| need_migrations | |||
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| fn compute_2229_migrations_precise_pass( | |||
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This function could use a comment =) why are there two passes? What does it mean for one to be "precise"?
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Those questions are not purely rhetorical. I'm also just legit unsure why there are two passes :)
| struct ConstainsDropField(Foo, Foo); | ||
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| // Test that if all paths starting at root variable that implement Drop are captured | ||
| // then it doesn't trigger the lint. |
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It occurs to me that the order in which these drops will execute may be different -- but I think that's ok. It seems pretty unlikely that this will be relevant. Still, I think we should document these assumptions -- maybe in the project-rfc-2229 repo? We're going to want to note them down in the Edition Migration Guide.
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(i.e., before, the closure would drop t, which would in turn drop its fields in order, but now the order of the fields in the closure may not match -- actually, if we wanted, we could sort the fields in the closure and fix that, couldn't we?)
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Yea sorting won't be hard,
For place_a, place_b, let c length of the common starting prefix of these places. Eg: for p.x.y and p.x.z then c = 2.
Then we can write a compartor which is essentially place_a.projections[c] < place_b.projections[c] => place_a < place_b
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@nikomatsakis I have updated the PR. There was no specific reason to do a two-pass implementation, so I have combined them |
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@bors r+ |
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📌 Commit 96c12f9 has been approved by |
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Rollup of 11 pull requests Successful merges: - rust-lang#80523 (#[doc(inline)] sym_generated) - rust-lang#80920 (Visit more targets when validating attributes) - rust-lang#81720 (Updated smallvec version due to RUSTSEC-2021-0003) - rust-lang#81891 ([rustdoc-json] Make `header` a vec of modifiers, and FunctionPointer consistent) - rust-lang#81912 (Implement the precise analysis pass for lint `disjoint_capture_drop_reorder`) - rust-lang#81914 (Fixing bad suggestion for `_` in `const` type when a function rust-lang#81885) - rust-lang#81919 (BTreeMap: fix internal comments) - rust-lang#81927 (Add a regression test for rust-lang#32498) - rust-lang#81965 (Fix MIR pretty printer for non-local DefIds) - rust-lang#82029 (Use debug log level for developer oriented logs) - rust-lang#82056 (fix ice (rust-lang#82032)) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
The precision pass for the lint prevents the lint from triggering for a variable (that was previously entirely captured by the closure) if all paths that need Drop starting at root variable have been captured by the closure.
r? @nikomatsakis