Merge pull request #75782 from glessard/rdar133343460-incorrectly-sendable

[stdlib] fix sendability of ManagedBufferPointer

Author: glessard

stdlib/public/core/ManagedBuffer.swift

@@ -374,6 +374,9 @@ public struct ManagedBufferPointer<
   }
 }
 
+@available(*, unavailable)
+extension ManagedBufferPointer: Sendable where Element: ~Copyable {}
+
 extension ManagedBufferPointer where Element: ~Copyable {
   /// The stored `Header` instance.
   @_preInverseGenerics

test/Concurrency/sendable_checking.swift

@@ -387,6 +387,12 @@ func testPointersAreNotSendable() {
     testSendable(rawMutableBuffer) // expected-warning {{conformance of 'UnsafeMutableRawBufferPointer' to 'Sendable' is unavailable}}
     testSendable(rawMutableBuffer.makeIterator()) // expected-warning {{conformance of 'UnsafeRawBufferPointer.Iterator' to 'Sendable' is unavailable}}
   }
+
+  func testManagedBuffers(buffer1: ManagedBuffer<Int, Int>, buffer2: ManagedBufferPointer<Int, Int>) {
+    testSendable(buffer1) // expected-warning {{conformance of 'ManagedBuffer<Header, Element>' to 'Sendable' is unavailable}}
+
+    testSendable(buffer2) // expected-warning {{conformance of 'ManagedBufferPointer<Header, Element>' to 'Sendable' is unavailable}}
+  }
 }
 
 @available(*, unavailable)