diff --git a/src/proc.h b/src/proc.h
index ec28b2388..7a589c50c 100644
--- a/src/proc.h
+++ b/src/proc.h
@@ -403,6 +403,7 @@ class job_t : noncopyable_t {
         bool notified_of_stop{false};
 
         /// Whether the exit status should be negated. This flag can only be set by the not builtin.
+        /// Two "not" prefixes on a single job cancel each other out.
         bool negate{false};
 
         /// This job is disowned, and should be removed from the active jobs list.
diff --git a/tests/checks/not.fish b/tests/checks/not.fish
new file mode 100644
index 000000000..77a03c419
--- /dev/null
+++ b/tests/checks/not.fish
@@ -0,0 +1,10 @@
+#RUN: %fish %s
+
+not true
+echo $status
+# CHECK: 1
+
+# Two "not" prefixes on a single job cancel each other out.
+not not sh -c 'exit 34'
+echo $status
+# CHECK: 34