Introduce a new implementation of implicit shadowing#8109
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retronym merged 2 commits intoscala:2.12.xfrom Jun 24, 2019
Merged
Introduce a new implementation of implicit shadowing#8109retronym merged 2 commits intoscala:2.12.xfrom
retronym merged 2 commits intoscala:2.12.xfrom
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Avoid building up a set of all in-scope implicits during each implicit search. Instead, do the filtering of shadowed implicits in a second pass.
With an opt-out system property
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Less ambitious version of #7757 which has proved hard to get over the line. |
retronym
commented
May 29, 2019
| // Collect candidates, the level at which each was found and build a set of their names | ||
| var iss = this.iss | ||
| while (!iss.isEmpty) { | ||
| var is = iss.head |
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While loops avoid ObjectRef-s here for the captured vars.
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I was going to lint that after ichoran mentioned how pernicious it is.
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Comparing execution time, again for Measuring allocation rate improvements: 0.90x reduction. |
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Scheduled a community build (link 404 until Seth provides the witticism) on the first commit, which is a bake-off between the old and new implementation that asserts identical results. |
diesalbla
reviewed
Jun 1, 2019
| /** Sorted list of eligible implicits. | ||
| */ | ||
| private def eligibleNew = { | ||
| final case class Candidate(info: ImplicitInfo, level: Int) |
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- As a farther step to remove extra allocations, we can unzip the
matchesarray into anArray[ImplicitInfo]and anArray[Int], and thus get rid of theCandidateclass. - Going farther, and assuming that 255 levels should be enough for anyone, perhaps we could make
levelinto anArray[Byte]?
diesalbla
approved these changes
Jun 2, 2019
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Avoid building up a set of all in-scope implicits during each implicit
search.
Instead, do the filtering of shadowed implicits in a second pass.