Add @discardableResult to mutating partition methods#274
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adityasingh2400 wants to merge 1 commit into
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Add @discardableResult to mutating partition methods#274adityasingh2400 wants to merge 1 commit into
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The mutating partition/stablePartition methods return the index of the first element of the second partition. That index is often not needed at the call site (e.g. bringForward(elementsSatisfying:) from Embracing Algorithms, WWDC 2018), which produced a spurious 'result of call is unused' warning. Mark these methods @discardableResult so callers may ignore the returned index without a warning. Fixes apple#67
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Problem
The mutating
partition(by:)/stablePartition(by:)family returns the index of the first element in the second partition, but the methods are not marked@discardableResult. Callers who only want the in-place partitioning side effect and don't need the pivot index get an unavoidable "result of call is unused" warning, as requested in #67.Change
Add
@discardableResultto the four mutating partition methods onMutableCollection(and theBidirectionalCollectionoverload).@discardableResultis purely additive and source-compatible: it only suppresses the unused-result warning for callers that ignore the return value, and changes no runtime behavior. Callers who use the returned index are unaffected.Verification
swift buildandswift testpass. No behavioral change; the attribute only affects unused-result diagnostics.Fixes #67.