Extend performance group with container-construction hints#1694
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mgajda wants to merge 1 commit intondmitchell:masterfrom
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Extend performance group with container-construction hints#1694mgajda wants to merge 1 commit intondmitchell:masterfrom
mgajda wants to merge 1 commit intondmitchell:masterfrom
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Adds fully-qualified rewrites for no-op container operations that are
semantically identical to their shorter form but cost an O(n) pass.
Every match uses fully-qualified module names so it only fires on the
specific API the user imported.
- Data.{Map,IntMap,HashMap}.{Strict,Lazy}.union with empty -> the map
- Data.{Set,HashSet}.union with empty -> the set
- Data.{Map,IntMap,HashMap}.Lazy.map id -> the map
- Data.{Set,HashSet}.map id -> the set
The Strict map-id rewrites are deliberately NOT added: removing the
call would change evaluation semantics for containers holding bottoms.
All rules live in the opt-in `performance` group (enabled: false).
Part of a set of independent PRs adding rule families to that group;
each PR creates its own `performance` group block which merges cleanly
with the others on the maintainer's end.
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Part of a set of independent PRs adding rules to the opt-in
performancegroup (disabled by default; enabled via--with-group=performanceor per-project config). Each PR in the setcreates its own
performancegroup block; the blocks merge cleanly.This one covers redundant container construction (identity rewrites).
Rules added
All fully-qualified so they fire only on the exact API users imported.
Data.{Map,IntMap,HashMap}.{Strict,Lazy}.union m empty(both orders) →mData.{Set,HashSet}.union s empty(both orders) →sData.{Map,IntMap,HashMap}.Lazy.map id m→mData.{Set,HashSet}.map id s→s