Issue #13020: Fix a reference leak when allocating a structsequence object fails.
Patch by Suman Saha.
diff --git a/Misc/NEWS b/Misc/NEWS
index 0bfbd38..ba09480 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -9,6 +9,9 @@
 Core and Builtins
 -----------------
 
+- Issue #13020: Fix a reference leak when allocating a structsequence object
+  fails.  Patch by Suman Saha.
+
 - Issue #11235: Fix OverflowError when trying to import a source file whose
   modification time doesn't fit in a 32-bit timestamp.
 
diff --git a/Objects/structseq.c b/Objects/structseq.c
index 58e15cb..dcc5457 100644
--- a/Objects/structseq.c
+++ b/Objects/structseq.c
@@ -201,6 +201,7 @@
 
     res = (PyStructSequence*) PyStructSequence_New(type);
     if (res == NULL) {
+        Py_DECREF(arg);
         return NULL;
     }
     for (i = 0; i < len; ++i) {