diff --git a/stdlib/public/core/SetAnyHashableExtensions.swift b/stdlib/public/core/SetAnyHashableExtensions.swift
index bff5639cc9ae7..bab822cf0dfe3 100644
--- a/stdlib/public/core/SetAnyHashableExtensions.swift
+++ b/stdlib/public/core/SetAnyHashableExtensions.swift
@@ -16,6 +16,7 @@
 
 extension Set where Element == AnyHashable {
   @inlinable
+  @discardableResult
   public mutating func insert<ConcreteElement: Hashable>(
     _ newMember: __owned ConcreteElement
   ) -> (inserted: Bool, memberAfterInsert: ConcreteElement) {