From 88fa53b5ea35b8da7e3f578254583e249cd58394 Mon Sep 17 00:00:00 2001
From: Shubhransh Gupta <54713516+shubhransh-gupta@users.noreply.github.com>
Date: Fri, 28 Aug 2026 21:33:54 +0530
Subject: [PATCH] Mark mutating partition functions as @discardableResult (#67)

---
 Guides/Partition.md                | 3 +++
 Sources/Algorithms/Partition.swift | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/Guides/Partition.md b/Guides/Partition.md
index 54678aa3a..4bfea2268 100644
--- a/Guides/Partition.md
+++ b/Guides/Partition.md
@@ -63,15 +63,18 @@ The `partitioningIndex(where:)` method is available on any `Collection` type.
 
 ```swift
 extension MutableCollection {
+    @discardableResult
     mutating func stablePartition(
         by belongsInSecondPartition: (Element) throws -> Bool
     ) rethrows -> Index
 
+    @discardableResult
     mutating func stablePartition(
         subrange: Range<Index>,
         by belongsInSecondPartition: (Element) throws -> Bool
     ) rethrows -> Index
 
+    @discardableResult
     mutating func partition(
         subrange: Range<Index>,
         by belongsInSecondPartition: (Element) throws -> Bool
diff --git a/Sources/Algorithms/Partition.swift b/Sources/Algorithms/Partition.swift
index 56fb8412a..647b5a744 100644
--- a/Sources/Algorithms/Partition.swift
+++ b/Sources/Algorithms/Partition.swift
@@ -22,6 +22,7 @@ extension MutableCollection {
   /// - Precondition:
   ///   `n == distance(from: range.lowerBound, to: range.upperBound)`
   @inlinable
+  @discardableResult
   internal mutating func stablePartition(
     count n: Int,
     subrange: Range<Index>,
@@ -63,6 +64,7 @@ extension MutableCollection {
   ///
   /// - Complexity: O(*n* log *n*), where *n* is the length of this collection.
   @inlinable
+  @discardableResult
   public mutating func stablePartition(
     subrange: Range<Index>,
     by belongsInSecondPartition: (Element) throws -> Bool
@@ -87,6 +89,7 @@ extension MutableCollection {
   ///
   /// - Complexity: O(*n* log *n*), where *n* is the length of this collection.
   @inlinable
+  @discardableResult
   public mutating func stablePartition(
     by belongsInSecondPartition: (Element) throws -> Bool
   ) rethrows -> Index {
@@ -122,6 +125,7 @@ extension MutableCollection {
   ///
   /// - Complexity: O(*n*) where n is the length of the collection.
   @inlinable
+  @discardableResult
   public mutating func partition(
     subrange: Range<Index>,
     by belongsInSecondPartition: (Element) throws -> Bool
@@ -166,6 +170,7 @@ extension MutableCollection where Self: BidirectionalCollection {
   ///
   /// - Complexity: O(*n*) where n is the length of the collection.
   @inlinable
+  @discardableResult
   public mutating func partition(
     subrange: Range<Index>,
     by belongsInSecondPartition: (Element) throws -> Bool