diff --git a/Sources/Testing/Attachments/Attachment.swift b/Sources/Testing/Attachments/Attachment.swift
index 1313b0d41..b22911919 100644
--- a/Sources/Testing/Attachments/Attachment.swift
+++ b/Sources/Testing/Attachments/Attachment.swift
@@ -193,6 +193,7 @@ public struct AnyAttachable: AttachableWrapper, Sendable, Copyable {
 
 // MARK: - Describing an attachment
 
+@_preInverseGenerics
 extension Attachment: CustomStringConvertible where AttachableValue: ~Copyable {
   /// @Metadata {
   ///   @Available(Swift, introduced: 6.2)