From d986c566a11d528e88ea6ada7a1b6d10717224f8 Mon Sep 17 00:00:00 2001
From: Karl <5254025+karwa@users.noreply.github.com>
Date: Tue, 16 Mar 2021 12:26:20 +0100
Subject: [PATCH 1/2] Make suffix functions inlinable

---
 Sources/Algorithms/Suffix.swift | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Sources/Algorithms/Suffix.swift b/Sources/Algorithms/Suffix.swift
index 0ebd0356..56966c77 100644
--- a/Sources/Algorithms/Suffix.swift
+++ b/Sources/Algorithms/Suffix.swift
@@ -45,7 +45,7 @@ extension Collection {
   ///   be called again.
   ///
   /// - Complexity: O(*n*), where *n* is the length of the collection.
-  @usableFromInline
+  @inlinable
   internal func endOfPrefix(
     while predicate: (Element) throws -> Bool
   ) rethrows -> Index {
@@ -71,7 +71,7 @@ extension BidirectionalCollection {
   ///   be called again.
   ///
   /// - Complexity: O(*n*), where *n* is the length of the collection.
-  @usableFromInline
+  @inlinable
   internal func startOfSuffix(
     while predicate: (Element) throws -> Bool
   ) rethrows -> Index {

From ba57786b8db4a50f92bfec127ce82c67be22fd17 Mon Sep 17 00:00:00 2001
From: Karl <5254025+karwa@users.noreply.github.com>
Date: Tue, 16 Mar 2021 12:49:24 +0100
Subject: [PATCH 2/2] Inline all the things!

---
 Sources/Algorithms/Chain.swift        | 14 +++++++-------
 Sources/Algorithms/Chunked.swift      | 25 +++++++++++++------------
 Sources/Algorithms/Combinations.swift |  9 +++++----
 Sources/Algorithms/Cycle.swift        |  4 ++--
 Sources/Algorithms/Indexed.swift      |  2 +-
 Sources/Algorithms/Intersperse.swift  | 13 +++++++++----
 Sources/Algorithms/LazySplit.swift    | 10 +++++-----
 Sources/Algorithms/Partition.swift    |  2 +-
 Sources/Algorithms/Permutations.swift | 10 +++++-----
 Sources/Algorithms/Product.swift      | 18 ++++++++++--------
 Sources/Algorithms/Rotate.swift       |  4 ++--
 Sources/Algorithms/Stride.swift       | 10 +++++-----
 Sources/Algorithms/Windows.swift      | 12 ++++++------
 13 files changed, 71 insertions(+), 62 deletions(-)

diff --git a/Sources/Algorithms/Chain.swift b/Sources/Algorithms/Chain.swift
index 311e341a..fc9f3ef0 100644
--- a/Sources/Algorithms/Chain.swift
+++ b/Sources/Algorithms/Chain.swift
@@ -19,7 +19,7 @@ public struct Chain2<Base1: Sequence, Base2: Sequence>
   /// The second sequence in this chain.
   public let base2: Base2
 
-  @usableFromInline
+  @inlinable
   internal init(base1: Base1, base2: Base2) {
     self.base1 = base1
     self.base2 = base2
@@ -35,7 +35,7 @@ extension Chain2: Sequence {
     @usableFromInline
     internal var iterator2: Base2.Iterator
     
-    @usableFromInline
+    @inlinable
     internal init(_ concatenation: Chain2) {
       iterator1 = concatenation.base1.makeIterator()
       iterator2 = concatenation.base2.makeIterator()
@@ -71,13 +71,13 @@ extension Chain2: Collection where Base1: Collection, Base2: Collection {
     internal let position: Representation
 
     /// Creates a new index into the first underlying collection.
-    @usableFromInline
+    @inlinable
     internal init(first i: Base1.Index) {
       position = .first(i)
     }
 
     /// Creates a new index into the second underlying collection.
-    @usableFromInline
+    @inlinable
     internal init(second i: Base2.Index) {
       position = .second(i)
     }
@@ -99,7 +99,7 @@ extension Chain2: Collection where Base1: Collection, Base2: Collection {
   
   /// Converts an index of `Base1` to the corresponding `Index` by mapping
   /// `base1.endIndex` to `base2.startIndex`.
-  @usableFromInline
+  @inlinable
   internal func convertIndex(_ i: Base1.Index) -> Index {
     i == base1.endIndex ? Index(second: base2.startIndex) : Index(first: i)
   }
@@ -157,7 +157,7 @@ extension Chain2: Collection where Base1: Collection, Base2: Collection {
       : offsetBackward(i, by: -n, limitedBy: limit)
   }
 
-  @usableFromInline
+  @inlinable
   internal func offsetForward(
     _ i: Index, by n: Int, limitedBy limit: Index
   ) -> Index? {
@@ -197,7 +197,7 @@ extension Chain2: Collection where Base1: Collection, Base2: Collection {
     }
   }
 
-  @usableFromInline
+  @inlinable
   internal func offsetBackward(
     _ i: Index, by n: Int, limitedBy limit: Index
   ) -> Index? {
diff --git a/Sources/Algorithms/Chunked.swift b/Sources/Algorithms/Chunked.swift
index 388ee4e3..f57b1fc7 100644
--- a/Sources/Algorithms/Chunked.swift
+++ b/Sources/Algorithms/Chunked.swift
@@ -27,7 +27,7 @@ public struct LazyChunked<Base: Collection, Subject> {
   @usableFromInline
   internal var firstUpperBound: Base.Index
   
-  @usableFromInline
+  @inlinable
   internal init(
     base: Base,
     projection: @escaping (Base.Element) -> Subject,
@@ -51,7 +51,7 @@ extension LazyChunked: LazyCollectionProtocol {
     @usableFromInline
     internal var baseRange: Range<Base.Index>
     
-    @usableFromInline
+    @inlinable
     internal init(_ baseRange: Range<Base.Index>) {
       self.baseRange = baseRange
     }
@@ -72,7 +72,7 @@ extension LazyChunked: LazyCollectionProtocol {
 
   /// Returns the index in the base collection of the end of the chunk starting
   /// at the given index.
-  @usableFromInline
+  @inlinable
   internal func endOfChunk(startingAt start: Base.Index) -> Base.Index {
     let subject = projection(base[start])
     return base[base.index(after: start)...]
@@ -112,7 +112,7 @@ extension LazyChunked: BidirectionalCollection
 {
   /// Returns the index in the base collection of the start of the chunk ending
   /// at the given index.
-  @usableFromInline
+  @inlinable
   internal func startOfChunk(endingAt end: Base.Index) -> Base.Index {
     let indexBeforeEnd = base.index(before: end)
     
@@ -174,7 +174,7 @@ extension Collection {
   /// predicate.
   ///
   /// - Complexity: O(*n*), where *n* is the length of this collection.
-  @usableFromInline
+  @inlinable
   internal func chunked<Subject>(
     on projection: (Element) throws -> Subject,
     by belongInSameGroup: (Subject, Subject) throws -> Bool
@@ -273,7 +273,7 @@ extension ChunkedByCount: Collection {
     @usableFromInline
     internal let baseRange: Range<Base.Index>
     
-    @usableFromInline
+    @inlinable
     internal init(_baseRange: Range<Base.Index>) {
       self.baseRange = _baseRange
     }
@@ -290,6 +290,7 @@ extension ChunkedByCount: Collection {
   }
   
   /// - Complexity: O(1)
+  @inlinable
   public subscript(i: Index) -> Element {
     precondition(i < endIndex, "Index out of range")
     return base[i.baseRange]
@@ -392,7 +393,7 @@ extension ChunkedByCount {
     return index
   }
   
-  @usableFromInline
+  @inlinable
   internal func offsetForward(
     _ i: Index, offsetBy distance: Int, limit: Index? = nil
   ) -> Index? {
@@ -406,8 +407,8 @@ extension ChunkedByCount {
   }
   
   // Convenience to compute offset backward base distance.
-  @inline(__always)
-  private func computeOffsetBackwardBaseDistance(
+  @inlinable
+  internal func computeOffsetBackwardBaseDistance(
     _ i: Index, _ distance: Int
   ) -> Int {
     if i == endIndex {
@@ -423,7 +424,7 @@ extension ChunkedByCount {
     return distance * chunkCount
   }
   
-  @usableFromInline
+  @inlinable
   internal func offsetBackward(
     _ i: Index, offsetBy distance: Int, limit: Index? = nil
   ) -> Index? {
@@ -438,8 +439,8 @@ extension ChunkedByCount {
   }
   
   // Helper to compute index(offsetBy:) index.
-  @inline(__always)
-  private func makeOffsetIndex(
+  @inlinable
+  internal func makeOffsetIndex(
     from i: Index, baseBound: Base.Index, distance: Int, baseDistance: Int,
     limit: Index?, by limitFn: (Base.Index, Base.Index) -> Bool
   ) -> Index? {
diff --git a/Sources/Algorithms/Combinations.swift b/Sources/Algorithms/Combinations.swift
index 07c19913..c1e8c1c6 100644
--- a/Sources/Algorithms/Combinations.swift
+++ b/Sources/Algorithms/Combinations.swift
@@ -27,7 +27,7 @@ public struct Combinations<Base: Collection> {
   /// - Parameters:
   ///   - base: The collection to iterate over for combinations.
   ///   - k: The expected size of each combination.
-  @usableFromInline
+  @inlinable
   internal init(_ base: Base, k: Int) {
     self.init(base, kRange: k...k)
   }
@@ -37,7 +37,7 @@ public struct Combinations<Base: Collection> {
   /// - Parameters:
   ///   - base: The collection to iterate over for combinations.
   ///   - kRange: The range of accepted sizes of combinations.
-  @usableFromInline
+  @inlinable
   internal init<R: RangeExpression>(
     _ base: Base, kRange: R
   ) where R.Bound == Int {
@@ -89,7 +89,7 @@ extension Combinations: Sequence {
     internal var kRange: Range<Int>
     
     /// Whether or not iteration is finished (`kRange` is empty)
-    @usableFromInline
+    @inlinable
     internal var isFinished: Bool {
       return kRange.isEmpty
     }
@@ -97,6 +97,7 @@ extension Combinations: Sequence {
     @usableFromInline
     internal var indexes: [Base.Index]
     
+    @inlinable
     internal init(_ combinations: Combinations) {
       self.base = combinations.base
       self.kRange = combinations.kRange ?? 0..<0
@@ -121,7 +122,7 @@ extension Combinations: Sequence {
     ///     [2, 3, 4] *
     ///     // Can't advance without needing to go past `base.endIndex`,
     ///     // so the iteration is finished.
-    @usableFromInline
+    @inlinable
     internal mutating func advance() {
       /// Advances `kRange` by incrementing its `lowerBound` until the range is
       /// empty, when iteration is finished.
diff --git a/Sources/Algorithms/Cycle.swift b/Sources/Algorithms/Cycle.swift
index fe3c9661..41d298bd 100644
--- a/Sources/Algorithms/Cycle.swift
+++ b/Sources/Algorithms/Cycle.swift
@@ -14,7 +14,7 @@ public struct Cycle<Base: Collection> {
   /// The collection to repeat.
   public let base: Base
   
-  @usableFromInline
+  @inlinable
   internal init(base: Base) {
     self.base = base
   }
@@ -29,7 +29,7 @@ extension Cycle: Sequence {
     @usableFromInline
     var current: Base.Index
     
-    @usableFromInline
+    @inlinable
     internal init(base: Base) {
       self.base = base
       self.current = base.startIndex
diff --git a/Sources/Algorithms/Indexed.swift b/Sources/Algorithms/Indexed.swift
index 09b3627e..d81c9a77 100644
--- a/Sources/Algorithms/Indexed.swift
+++ b/Sources/Algorithms/Indexed.swift
@@ -18,7 +18,7 @@ public struct Indexed<Base: Collection> {
   /// The base collection.
   public let base: Base
   
-  @usableFromInline
+  @inlinable
   internal init(base: Base) {
     self.base = base
   }
diff --git a/Sources/Algorithms/Intersperse.swift b/Sources/Algorithms/Intersperse.swift
index aa9a32a7..165881bf 100644
--- a/Sources/Algorithms/Intersperse.swift
+++ b/Sources/Algorithms/Intersperse.swift
@@ -18,7 +18,7 @@ public struct Intersperse<Base: Sequence> {
   @usableFromInline
   internal let separator: Base.Element
   
-  @usableFromInline
+  @inlinable
   internal init(base: Base, separator: Base.Element) {
     self.base = base
     self.separator = separator
@@ -37,7 +37,7 @@ extension Intersperse: Sequence {
     @usableFromInline
     internal var state = State.start
     
-    @usableFromInline
+    @inlinable
     internal init(iterator: Base.Iterator, separator: Base.Element) {
       self.iterator = iterator
       self.separator = separator
@@ -89,6 +89,11 @@ extension Intersperse: Collection where Base: Collection {
     @usableFromInline
     internal let representation: Representation
 
+    @inlinable
+    init(representation: Representation) {
+      self.representation = representation
+    }
+
     @inlinable
     public static func < (lhs: Index, rhs: Index) -> Bool {
       switch (lhs.representation, rhs.representation) {
@@ -101,12 +106,12 @@ extension Intersperse: Collection where Base: Collection {
       }
     }
     
-    @usableFromInline
+    @inlinable
     static func element(_ index: Base.Index) -> Self {
       Self(representation: .element(index))
     }
 
-    @usableFromInline
+    @inlinable
     static func separator(next: Base.Index) -> Self {
       Self(representation: .separator(next: next))
     }
diff --git a/Sources/Algorithms/LazySplit.swift b/Sources/Algorithms/LazySplit.swift
index 5f6dae6e..9241e636 100644
--- a/Sources/Algorithms/LazySplit.swift
+++ b/Sources/Algorithms/LazySplit.swift
@@ -34,7 +34,7 @@ public struct LazySplitSequence<Base: Sequence> {
   @usableFromInline
   internal let omittingEmptySubsequences: Bool
 
-  @usableFromInline
+  @inlinable
   internal init(
     base: Base,
     isSeparator: @escaping (Base.Element) -> Bool,
@@ -72,7 +72,7 @@ extension LazySplitSequence {
     @usableFromInline
     internal var sequenceLength = 0
 
-    @usableFromInline
+    @inlinable
     internal init(
       base: Base.Iterator,
       whereSeparator: @escaping (Base.Element) -> Bool,
@@ -360,7 +360,7 @@ public struct LazySplitCollection<Base: Collection> {
   @usableFromInline
   internal var _startIndex: Index
 
-  @usableFromInline
+  @inlinable
   internal init(
     base: Base,
     isSeparator: @escaping (Base.Element) -> Bool,
@@ -415,7 +415,7 @@ extension LazySplitCollection: LazyCollectionProtocol {
     @usableFromInline
     internal let splitCount: Int
 
-    @usableFromInline
+    @inlinable
     internal init(
       baseRange: Range<Base.Index>,
       sequenceLength: Int,
@@ -441,7 +441,7 @@ extension LazySplitCollection: LazyCollectionProtocol {
 
   /// Returns the index of the subsequence starting at or after the given base
   /// collection index.
-  @usableFromInline
+  @inlinable
   internal func indexForSubsequence(
     atOrAfter lowerBound: Base.Index,
     sequenceLength: Int,
diff --git a/Sources/Algorithms/Partition.swift b/Sources/Algorithms/Partition.swift
index af81eae4..66a0b011 100644
--- a/Sources/Algorithms/Partition.swift
+++ b/Sources/Algorithms/Partition.swift
@@ -21,7 +21,7 @@ extension MutableCollection {
   /// - Complexity: O(*n* log *n*), where *n* is the number of elements.
   /// - Precondition:
   ///   `n == distance(from: range.lowerBound, to: range.upperBound)`
-  @usableFromInline
+  @inlinable
   internal mutating func stablePartition(
     count n: Int,
     subrange: Range<Index>,
diff --git a/Sources/Algorithms/Permutations.swift b/Sources/Algorithms/Permutations.swift
index 81f8f0d8..e34ecfaf 100644
--- a/Sources/Algorithms/Permutations.swift
+++ b/Sources/Algorithms/Permutations.swift
@@ -28,7 +28,7 @@ public struct Permutations<Base: Collection> {
   ///   - base: The collection to iterate over for permutations
   ///   - k: The expected size of each permutation, or `nil` (default) to
   ///   iterate over all permutations of the same size as the base collection.
-  @usableFromInline
+  @inlinable
   internal init(_ base: Base, k: Int? = nil) {
     let kRange: ClosedRange<Int>?
     if let countToChoose = k {
@@ -45,7 +45,7 @@ public struct Permutations<Base: Collection> {
   ///   - base: The collection to iterate over for permutations.
   ///   - kRange: The range of accepted sizes of permutations, or `nil` to
   ///   iterate over all permutations of the same size as the base collection.
-  @usableFromInline
+  @inlinable
   internal init<R: RangeExpression>(
     _ base: Base, kRange: R?
   ) where R.Bound == Int {
@@ -84,7 +84,7 @@ extension Permutations: Sequence {
     internal var kRange: Range<Int>
     
     /// Whether or not iteration is finished (`kRange` is empty)
-    @usableFromInline
+    @inlinable
     internal var isFinished: Bool {
       return kRange.isEmpty
     }
@@ -92,7 +92,7 @@ extension Permutations: Sequence {
     @usableFromInline
     internal var indexes: [Base.Index]
     
-    @usableFromInline
+    @inlinable
     internal init(_ permutations: Permutations) {
       self.base = permutations.base
       self.baseCount = permutations.baseCount
@@ -111,7 +111,7 @@ extension Permutations: Sequence {
     ///   is in ascending order.
     ///
     /// - Complexity: O(*n*), where *n* is the length of the collection.
-    @usableFromInline
+    @inlinable
     internal mutating func nextState() -> Bool {
       let countToChoose = self.kRange.lowerBound
       let edge = countToChoose - 1
diff --git a/Sources/Algorithms/Product.swift b/Sources/Algorithms/Product.swift
index 8b353ba8..870ee1b7 100644
--- a/Sources/Algorithms/Product.swift
+++ b/Sources/Algorithms/Product.swift
@@ -16,7 +16,7 @@ public struct Product2<Base1: Sequence, Base2: Collection> {
   /// The inner sequence in the product.
   public let base2: Base2
   
-  @usableFromInline
+  @inlinable
   internal init(_ base1: Base1, _ base2: Base2) {
     self.base1 = base1
     self.base2 = base2
@@ -35,7 +35,7 @@ extension Product2: Sequence {
     @usableFromInline
     internal let base2: Base2
 
-    @usableFromInline
+    @inlinable
     internal init(_ c: Product2) {
       self.base2 = c.base2
       self.i1 = c.base1.makeIterator()
@@ -90,7 +90,7 @@ extension Product2: Collection where Base1: Collection {
     @usableFromInline
     internal var i2: Base2.Index
     
-    @usableFromInline
+    @inlinable
     internal init(i1: Base1.Index, i2: Base2.Index) {
       self.i1 = i1
       self.i2 = i2
@@ -128,7 +128,7 @@ extension Product2: Collection where Base1: Collection {
   /// Forms an index from a pair of base indices, normalizing
   /// `(i, base2.endIndex)` to `(base1.index(after: i), base2.startIndex)` if
   /// necessary.
-  @usableFromInline
+  @inlinable
   internal func normalizeIndex(_ i1: Base1.Index, _ i2: Base2.Index) -> Index {
     i2 == base2.endIndex
       ? Index(i1: base1.index(after: i1), i2: base2.startIndex)
@@ -195,6 +195,7 @@ extension Product2: Collection where Base1: Collection {
     }
   }
   
+  @inlinable
   public func index(_ i: Index, offsetBy distance: Int) -> Index {
     guard distance != 0 else { return i }
     
@@ -203,6 +204,7 @@ extension Product2: Collection where Base1: Collection {
       : offsetBackward(i, by: -distance)
   }
   
+  @inlinable
   public func index(
     _ i: Index,
     offsetBy distance: Int,
@@ -219,21 +221,21 @@ extension Product2: Collection where Base1: Collection {
     }
   }
 
-  @usableFromInline
+  @inlinable
   internal func offsetForward(_ i: Index, by distance: Int) -> Index {
     guard let index = offsetForward(i, by: distance, limitedBy: endIndex)
       else { fatalError("Index is out of bounds") }
     return index
   }
   
-  @usableFromInline
+  @inlinable
   internal func offsetBackward(_ i: Index, by distance: Int) -> Index {
     guard let index = offsetBackward(i, by: distance, limitedBy: startIndex)
       else { fatalError("Index is out of bounds") }
     return index
   }
   
-  @usableFromInline
+  @inlinable
   internal func offsetForward(
     _ i: Index, by distance: Int, limitedBy limit: Index
   ) -> Index? {
@@ -311,7 +313,7 @@ extension Product2: Collection where Base1: Collection {
       .map { i2 in Index(i1: i1, i2: i2) }
   }
 
-  @usableFromInline
+  @inlinable
   internal func offsetBackward(
     _ i: Index, by distance: Int, limitedBy limit: Index
   ) -> Index? {
diff --git a/Sources/Algorithms/Rotate.swift b/Sources/Algorithms/Rotate.swift
index 08799ed6..094b1d9d 100644
--- a/Sources/Algorithms/Rotate.swift
+++ b/Sources/Algorithms/Rotate.swift
@@ -29,7 +29,7 @@ extension MutableCollection where Self: BidirectionalCollection {
   ///
   /// - Postcondition: For returned indices `(lower, upper)`:
   ///   `lower == limit || upper == limit`
-  @usableFromInline
+  @inlinable
   @discardableResult
   internal mutating func _reverse(
     subrange: Range<Index>, until limit: Index
@@ -94,7 +94,7 @@ extension MutableCollection {
   ///   - distance(from: lhs.lowerBound, to: p) == distance(from:
   ///     rhs.lowerBound, to: q)
   ///   - p == lhs.upperBound || q == rhs.upperBound
-  @usableFromInline
+  @inlinable
   internal mutating func _swapNonemptySubrangePrefixes(
     _ lhs: Range<Index>, _ rhs: Range<Index>
   ) -> (Index, Index) {
diff --git a/Sources/Algorithms/Stride.swift b/Sources/Algorithms/Stride.swift
index a4ce4a15..347825b8 100644
--- a/Sources/Algorithms/Stride.swift
+++ b/Sources/Algorithms/Stride.swift
@@ -61,7 +61,7 @@ public struct StrideSequence<Base: Sequence>: Sequence {
   @usableFromInline
   internal let stride: Int
   
-  @usableFromInline
+  @inlinable
   internal init(base: Base, stride: Int) {
     precondition(stride > 0, "striding must be greater than zero")
     self.base = base
@@ -82,7 +82,7 @@ extension StrideSequence {
     @usableFromInline
     internal var striding: Bool = false
     
-    @usableFromInline
+    @inlinable
     internal init(iterator: Base.Iterator, stride: Int) {
       self.iterator = iterator
       self.stride = stride
@@ -122,7 +122,7 @@ public struct StrideCollection<Base: Collection> {
   @usableFromInline
   internal let stride: Int
   
-  @usableFromInline
+  @inlinable
   internal init(base: Base, stride: Int) {
     precondition(stride > 0, "striding must be greater than zero")
     self.base = base
@@ -190,7 +190,7 @@ extension StrideCollection: Collection {
       : offsetBackward(i, offsetBy: -n, limitedBy: limit)
   }
   
-  @usableFromInline
+  @inlinable
   internal func offsetForward(
     _ i: Index,
     offsetBy n: Int,
@@ -220,7 +220,7 @@ extension StrideCollection: Collection {
     }
   }
   
-  @usableFromInline
+  @inlinable
   internal func offsetBackward(
     _ i: Index,
     offsetBy n: Int,
diff --git a/Sources/Algorithms/Windows.swift b/Sources/Algorithms/Windows.swift
index 8a2ac191..03f9fad6 100644
--- a/Sources/Algorithms/Windows.swift
+++ b/Sources/Algorithms/Windows.swift
@@ -53,7 +53,7 @@ public struct Windows<Base: Collection> {
   @usableFromInline
   internal var firstUpperBound: Base.Index?
 
-  @usableFromInline
+  @inlinable
   internal init(base: Base, size: Int) {
     precondition(size > 0, "Windows size must be greater than zero")
     self.base = base
@@ -72,7 +72,7 @@ extension Windows: Collection {
     @usableFromInline
     internal var upperBound: Base.Index
     
-    @usableFromInline
+    @inlinable
     internal init(lowerBound: Base.Index, upperBound: Base.Index) {
       self.lowerBound = lowerBound
       self.upperBound = upperBound
@@ -150,21 +150,21 @@ extension Windows: Collection {
     }
   }
   
-  @usableFromInline
+  @inlinable
   internal func offsetForward(_ i: Index, by distance: Int) -> Index {
     guard let index = offsetForward(i, by: distance, limitedBy: endIndex)
       else { fatalError("Index is out of bounds") }
     return index
   }
   
-  @usableFromInline
+  @inlinable
   internal func offsetBackward(_ i: Index, by distance: Int) -> Index {
     guard let index = offsetBackward(i, by: distance, limitedBy: startIndex)
       else { fatalError("Index is out of bounds") }
     return index
   }
   
-  @usableFromInline
+  @inlinable
   internal func offsetForward(
     _ i: Index, by distance: Int, limitedBy limit: Index
   ) -> Index? {
@@ -235,7 +235,7 @@ extension Windows: Collection {
     }
   }
   
-  @usableFromInline
+  @inlinable
   internal func offsetBackward(
       _ i: Index, by distance: Int, limitedBy limit: Index
     ) -> Index? {