Use UInt instead of a pointer for consistency

Author: grynspan

Documentation/ABI/TestContent.md

@@ -45,7 +45,7 @@ typealias Accessor = @convention(c) (
   _ outValue: UnsafeMutableRawPointer,
   _ type: UnsafeRawPointer,
   _ hint: UnsafeRawPointer?,
-  _ reserved: UnsafeRawPointer?
+  _ reserved: UInt
 ) -> CBool
 
 typealias TestContentRecord = (
@@ -65,7 +65,7 @@ typedef bool (* SWTAccessor)(
   void *outValue,
   const void *type,
   const void *_Nullable hint,
-  const void *_Nullable reserved
+  uintptr_t reserved
 );
 
 struct SWTTestContentRecord {
@@ -143,7 +143,7 @@ record matches what the caller is looking for. If the caller passes `nil` as the
 filtering is performed.)
 
 The fourth argument to this function, `reserved`, is reserved for future use.
-Accessor functions should assume it is `nil` and must not access it.
+Accessor functions should assume it is `0` and must not access it.
 
 The concrete Swift type of the value written to `outValue`, the type pointed to
 by `type`, and the value pointed to by `hint` depend on the kind of record:

Sources/Testing/Discovery+Macro.swift

@@ -29,7 +29,7 @@ public typealias __TestContentRecordAccessor = @convention(c) (
   _ outValue: UnsafeMutableRawPointer,
   _ type: UnsafeRawPointer,
   _ hint: UnsafeRawPointer?,
-  _ reserved: UnsafeRawPointer?
+  _ reserved: UInt
 ) -> CBool
 
 /// The content of a test content record.

Sources/_TestDiscovery/TestContentRecord.swift

@@ -25,7 +25,7 @@ private typealias _TestContentRecordAccessor = @convention(c) (
   _ outValue: UnsafeMutableRawPointer,
   _ type: UnsafeRawPointer,
   _ hint: UnsafeRawPointer?,
-  _ reserved: UnsafeRawPointer?
+  _ reserved: UInt
 ) -> CBool
 
 /// The content of a test content record.
@@ -156,10 +156,10 @@ public struct TestContentRecord<T> where T: DiscoverableAsTestContent & ~Copyabl
       withUnsafeTemporaryAllocation(of: T.self, capacity: 1) { buffer in
         let initialized = if let hint {
           withUnsafePointer(to: hint) { hint in
-            accessor(buffer.baseAddress!, type, hint, nil)
+            accessor(buffer.baseAddress!, type, hint, 0)
           }
         } else {
-          accessor(buffer.baseAddress!, type, nil, nil)
+          accessor(buffer.baseAddress!, type, nil, 0)
         }
         guard initialized else {
           return nil