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After typechk use closure_captures #6
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change We can only access typechk tables for definitions in the same (i.e. local) crate. So we need to pass the local id to read the typechk tables. |
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Currently closure_captures only provides infromation about the declaration of a captured variable and not the access within the closure. We need information about access to report information like unused variables that was implemented as part of rust-lang/rust#72465. This is information is not currently avaialble through typechk tables but however when we refector closure_captures to use Waiting on #7 to make more progress. Zulip stream: https://rust-lang.zulipchat.com/#narrow/stream/189812-t-compiler.2Fwg-rfc-2229/topic/upvar.20access.20spans |
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Nov 14, 2020
…akis RFC-2229: Implement Precise Capture Analysis ### This PR introduces - Feature gate for RFC-2229 (incomplete) `capture_disjoint_field` - Rustc Attribute to print out the capture analysis `rustc_capture_analysis` - Precise capture analysis ### Description of the analysis 1. If the feature gate is not set then all variables that are not local to the closure will be added to the list of captures. (This is for backcompat) 2. The rest of the analysis is based entirely on how the captured `Place`s are used within the closure. Precise information (i.e. projections) about the `Place` is maintained throughout. 3. To reduce the amount of information we need to keep track of, we do a minimization step. In this step, we determine a list such that no Place within this list represents an ancestor path to another entry in the list. Check rust-lang/project-rfc-2229#9 for more detailed examples. 4. To keep the compiler functional as before we implement a Bridge between the results of this new analysis to existing data structures used for closure captures. Note the new capture analysis results are only part of MaybeTypeckTables that is the information is only available during typeck-ing. ### Known issues - Statements like `let _ = x` will make the compiler ICE when used within a closure with the feature enabled. More generally speaking the issue is caused by `let` statements that create no bindings and are init'ed using a Place expression. ### Testing We removed the code that would handle the case where the feature gate is not set, to enable the feature as default and did a bors try and perf run. More information here: rust-lang#78762 ### Thanks This has been slowly in the works for a while now. I want to call out `@Azhng` `@ChrisPardy` `@null-sleep` `@jenniferwills` `@logmosier` `@roxelo` for working on this and the previous PRs that led up to this, `@nikomatsakis` for guiding us. Closes rust-lang/project-rfc-2229#7 Closes rust-lang/project-rfc-2229#9 Closes rust-lang/project-rfc-2229#6 Closes rust-lang/project-rfc-2229#19 r? `@nikomatsakis`
bors
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Nov 17, 2020
RFC-2229: Implement Precise Capture Analysis ### This PR introduces - Feature gate for RFC-2229 (incomplete) `capture_disjoint_field` - Rustc Attribute to print out the capture analysis `rustc_capture_analysis` - Precise capture analysis ### Description of the analysis 1. If the feature gate is not set then all variables that are not local to the closure will be added to the list of captures. (This is for backcompat) 2. The rest of the analysis is based entirely on how the captured `Place`s are used within the closure. Precise information (i.e. projections) about the `Place` is maintained throughout. 3. To reduce the amount of information we need to keep track of, we do a minimization step. In this step, we determine a list such that no Place within this list represents an ancestor path to another entry in the list. Check rust-lang/project-rfc-2229#9 for more detailed examples. 4. To keep the compiler functional as before we implement a Bridge between the results of this new analysis to existing data structures used for closure captures. Note the new capture analysis results are only part of MaybeTypeckTables that is the information is only available during typeck-ing. ### Known issues - Statements like `let _ = x` will make the compiler ICE when used within a closure with the feature enabled. More generally speaking the issue is caused by `let` statements that create no bindings and are init'ed using a Place expression. ### Testing We removed the code that would handle the case where the feature gate is not set, to enable the feature as default and did a bors try and perf run. More information here: rust-lang#78762 ### Thanks This has been slowly in the works for a while now. I want to call out `@Azhng` `@ChrisPardy` `@null-sleep` `@jenniferwills` `@logmosier` `@roxelo` for working on this and the previous PRs that led up to this, `@nikomatsakis` for guiding us. Closes rust-lang/project-rfc-2229#7 Closes rust-lang/project-rfc-2229#9 Closes rust-lang/project-rfc-2229#6 Closes rust-lang/project-rfc-2229#19 r? `@nikomatsakis`
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Since
upvars_mentionedmight not be same as paths that are captured, once type check is done, we know the list of captured path and we should be using that instead.The text was updated successfully, but these errors were encountered: