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Merge pull request #9847 from pennae/inherit-from-dedup

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deduplicate inherit-from source expr work
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Robert Hensing 2024-02-26 20:25:58 +01:00 • committed by GitHub
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doc/manual/rl-next/inherit-from-by-need.md Normal file
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synopsis: "`inherit (x) ...` evaluates `x` only once"
prs: 9847
---
`inherit (x) a b ...` now evaluates the expression `x` only once for all inherited attributes rather than once for each inherited attribute.
This does not usually have a measurable impact, but side-effects (such as `builtins.trace`) would be duplicated and expensive expressions (such as derivations) could cause a measurable slowdown.