Update SpanExtras.swift for strict @Lifetime checking.

These tests can't be fully enabled until this is fixed:

rdar://147194789 ([nonescapable] 'mutating get' causes a type checking error for
non-existent _read accessor)

Author: atrick

test/SILOptimizer/Inputs/SpanExtras.swift

@@ -184,6 +184,7 @@ extension MutableSpan where Element: BitwiseCopyable {
 extension Span where Element: ~Copyable {
 
   @_alwaysEmitIntoClient
+  @lifetime(borrow mutableSpan)
   public init(_unsafeMutableSpan mutableSpan: borrowing MutableSpan<Element>) {
     let pointer = mutableSpan._pointer?.assumingMemoryBound(to: Element.self)
     let buffer = UnsafeBufferPointer(start: pointer, count: mutableSpan.count)
@@ -215,6 +216,7 @@ extension MutableSpan where Element: ~Copyable {
 extension RawSpan {
 
   @_alwaysEmitIntoClient
+  @lifetime(borrow mutableSpan)
   public init<Element: BitwiseCopyable>(
     _unsafeMutableSpan mutableSpan: borrowing MutableSpan<Element>
   ) {
@@ -286,7 +288,10 @@ extension MutableSpan where Element: BitwiseCopyable {
   /// - Returns: a RawSpan over the memory represented by this span
   @unsafe //FIXME: remove when the lifetime inference is fixed
   @_alwaysEmitIntoClient
-  public var _unsafeRawSpan: RawSpan { RawSpan(_unsafeMutableSpan: self) }
+  public var _unsafeRawSpan: RawSpan {
+    @lifetime(borrow self)
+    get { RawSpan(_unsafeMutableSpan: self) }
+  }
 }
 
 @available(macOS 9999, iOS 9999, tvOS 9999, watchOS 9999, visionOS 9999, *)
@@ -300,10 +305,12 @@ extension MutableSpan where Element: ~Copyable {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   public subscript(_ position: Index) -> Element {
+    @lifetime(borrow self)
     _read {
       precondition(indices.contains(position), "index out of bounds")
       yield self[unchecked: position]
     }
+    @lifetime(borrow self)
     _modify {
       precondition(indices.contains(position), "index out of bounds")
       yield &self[unchecked: position]
@@ -323,6 +330,7 @@ extension MutableSpan where Element: ~Copyable {
     unsafeAddress {
       UnsafePointer(_unsafeAddressOfElement(unchecked: position))
     }
+    @lifetime(self: copy self)
     unsafeMutableAddress {
       _unsafeAddressOfElement(unchecked: position)
     }
@@ -342,12 +350,14 @@ extension MutableSpan where Element: ~Copyable {
 @available(macOS 9999, iOS 9999, tvOS 9999, watchOS 9999, visionOS 9999, *)
 extension MutableSpan where Element: ~Copyable {
 
+  @lifetime(self: copy self)
   public mutating func swapAt(_ i: Index, _ j: Index) {
     precondition(indices.contains(Index(i)))
     precondition(indices.contains(Index(j)))
     swapAt(unchecked: i, unchecked: j)
   }
 
+  @lifetime(self: copy self)
   public mutating func swapAt(unchecked i: Index, unchecked j: Index) {
     let pi = _unsafeAddressOfElement(unchecked: i)
     let pj = _unsafeAddressOfElement(unchecked: j)
@@ -372,6 +382,7 @@ extension MutableSpan where Element: BitwiseCopyable {
       precondition(indices.contains(position))
       return self[unchecked: position]
     }
+    @lifetime(self: copy self)
     set {
       precondition(indices.contains(position))
       self[unchecked: position] = newValue
@@ -392,6 +403,7 @@ extension MutableSpan where Element: BitwiseCopyable {
       let offset = position&*MemoryLayout<Element>.stride
       return _start().loadUnaligned(fromByteOffset: offset, as: Element.self)
     }
+    @lifetime(self: copy self)
     set {
       let offset = position&*MemoryLayout<Element>.stride
       _start().storeBytes(of: newValue, toByteOffset: offset, as: Element.self)
@@ -412,6 +424,7 @@ extension MutableSpan where Element: ~Copyable {
 
   //FIXME: mark closure parameter as non-escaping
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func withUnsafeMutableBufferPointer<E: Error, Result: ~Copyable>(
     _ body: (UnsafeMutableBufferPointer<Element>) throws(E) -> Result
   ) throws(E) -> Result {
@@ -440,6 +453,7 @@ extension MutableSpan where Element: BitwiseCopyable {
 
   //FIXME: mark closure parameter as non-escaping
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func withUnsafeMutableBytes<E: Error, Result: ~Copyable>(
     _ body: (_ buffer: UnsafeMutableRawBufferPointer) throws(E) -> Result
   ) throws(E) -> Result {
@@ -456,13 +470,15 @@ extension MutableSpan where Element: BitwiseCopyable {
 extension MutableSpan {
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func update(repeating repeatedValue: Element) {
     _start().withMemoryRebound(to: Element.self, capacity: count) {
       $0.update(repeating: repeatedValue, count: count)
     }
   }
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func update<S: Sequence>(
     from source: S
   ) -> (unwritten: S.Iterator, index: Index) where S.Element == Element {
@@ -472,6 +488,7 @@ extension MutableSpan {
   }
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func update(
     from elements: inout some IteratorProtocol<Element>
   ) -> Index {
@@ -485,6 +502,7 @@ extension MutableSpan {
   }
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func update(
     fromContentsOf source: some Collection<Element>
   ) -> Index {
@@ -505,6 +523,7 @@ extension MutableSpan {
   }
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func update(fromContentsOf source: Span<Element>) -> Index {
     guard !source.isEmpty else { return 0 }
     precondition(
@@ -520,6 +539,7 @@ extension MutableSpan {
   }
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func update(
     fromContentsOf source: borrowing MutableSpan<Element>
   ) -> Index {
@@ -532,6 +552,7 @@ extension MutableSpan {
 extension MutableSpan where Element: BitwiseCopyable {
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func update(
     repeating repeatedValue: Element
   ) where Element: BitwiseCopyable {
@@ -544,6 +565,7 @@ extension MutableSpan where Element: BitwiseCopyable {
   }
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func update<S: Sequence>(
     from source: S
   ) -> (unwritten: S.Iterator, index: Index)
@@ -554,6 +576,7 @@ extension MutableSpan where Element: BitwiseCopyable {
   }
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func update(
     from elements: inout some IteratorProtocol<Element>
   ) -> Index {
@@ -567,6 +590,7 @@ extension MutableSpan where Element: BitwiseCopyable {
   }
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func update(
     fromContentsOf source: some Collection<Element>
   ) -> Index where Element: BitwiseCopyable {
@@ -587,6 +611,7 @@ extension MutableSpan where Element: BitwiseCopyable {
   }
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func update(
     fromContentsOf source: Span<Element>
   ) -> Index where Element: BitwiseCopyable {
@@ -604,6 +629,7 @@ extension MutableSpan where Element: BitwiseCopyable {
   }
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func update(
     fromContentsOf source: borrowing MutableSpan<Element>
   ) -> Index where Element: BitwiseCopyable {
@@ -667,6 +693,7 @@ extension OutputSpan where Element: ~Copyable {
 @available(macOS 9999, *)
 @available(macOS 9999, *)
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func append(_ value: consuming Element) {
     precondition(_initialized < capacity, "Output buffer overflow")
     let p = _start.advanced(by: _initialized&*MemoryLayout<Element>.stride)
@@ -696,6 +723,7 @@ extension OutputSpan where Element: ~Copyable {
 extension OutputSpan {
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func append(repeating repeatedValue: Element, count: Int) {
     let available = capacity &- _initialized
     precondition(
@@ -711,6 +739,7 @@ extension OutputSpan {
   }
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func append<S>(
     from elements: S
   ) -> S.Iterator where S: Sequence, S.Element == Element {
@@ -720,6 +749,7 @@ extension OutputSpan {
   }
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func append(
     from elements: inout some IteratorProtocol<Element>
   ) {
@@ -732,6 +762,7 @@ extension OutputSpan {
   }
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func append(
     fromContentsOf source: some Collection<Element>
   ) {
@@ -762,6 +793,7 @@ extension OutputSpan {
   }
 
   //FIXME: remove once rdar://136838539 & rdar://136849171 are fixed
+  @lifetime(self: copy self)
   public mutating func append(
     fromContentsOf source: UnsafeBufferPointer<Element>
   ) {
@@ -779,6 +811,7 @@ extension OutputSpan {
 
   //FIXME: rdar://136838539 & rdar://136849171
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func append(
     fromContentsOf source: Span<Element>
   ) {
@@ -797,6 +830,7 @@ extension OutputSpan {
   }
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func append(fromContentsOf source: borrowing MutableSpan<Element>) {
     source.withUnsafeBufferPointer { append(fromContentsOf: $0) }
   }
@@ -806,6 +840,7 @@ extension OutputSpan {
 extension OutputSpan where Element: ~Copyable {
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func moveAppend(
     fromContentsOf source: consuming Self
   ) {
@@ -824,6 +859,7 @@ extension OutputSpan where Element: ~Copyable {
   }
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func moveAppend(
     fromContentsOf source: UnsafeMutableBufferPointer<Element>
   ) {
@@ -849,6 +885,7 @@ extension OutputSpan where Element: ~Copyable {
 extension OutputSpan {
 
   @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
   public mutating func moveAppend(
     fromContentsOf source: Slice<UnsafeMutableBufferPointer<Element>>
   ) {
@@ -875,16 +912,19 @@ extension OutputSpan where Element: ~Copyable {
     }
   }
 
+  /* FIXME: rdar://147194789 ([nonescapable] 'mutating get' causes a
+     type checking error for non-existent _read accessor)
   @_alwaysEmitIntoClient
   public var mutableSpan: MutableSpan<Element> {
-//    @lifetime(inout self) // this just crashes the compiler
+    @lifetime(borrow self)
     mutating get { // the accessor must provide a mutable projection
       let pointer = _pointer?.assumingMemoryBound(to: Element.self)
       let buffer = UnsafeMutableBufferPointer(start: pointer, count: _initialized)
       let span = MutableSpan(_unsafeElements: buffer)
       return _overrideLifetime(span, mutating: &self)
     }
   }
+   */
 }
 
 @available(macOS 9999, iOS 9999, tvOS 9999, watchOS 9999, visionOS 9999, *)