1 files changed, 7 insertions, 0 deletions
diff --git a/third_party/nix/src/libutil/util.hh b/third_party/nix/src/libutil/util.hh
index c39a6f06a5cf..ede83164de2e 100644
--- a/third_party/nix/src/libutil/util.hh
+++ b/third_party/nix/src/libutil/util.hh
@@ -390,6 +390,11 @@ class Callback {
     }
   }
 
+// The unused-variable assert is disabled in this block because the
+// `prev` variables are only used in debug mode (in the asserts).
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunused-variable"
+
   void operator()(T&& t) noexcept {
     auto prev = done.test_and_set();
     assert(!prev);
@@ -406,6 +411,8 @@ class Callback {
     promise.set_exception(exc);
     fun(promise.get_future());
   }
+
+#pragma clang diagnostic pop
 };
 
 /* Start a thread that handles various signals. Also block those signals