port: advance VC6 typeobject frontier and preserve regression coverage

scripts/vc6-tupleobject-repeat-dest-end-c89.test.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+"""Check only tuplerepeat's dest_end declaration and assignment order."""
+import re
+import sys
+from pathlib import Path
+
+source = Path(sys.argv[1] if len(sys.argv) > 1 else "cpython/Objects/tupleobject.c")
+match = re.search(
+    r"tuplerepeat\(PyTupleObject \*a, Py_ssize_t n\)\n\{(.*?)\n\}",
+    source.read_text(),
+    re.S,
+)
+assert match, "tuplerepeat definition missing"
+body = match.group(1)
+assert re.match(
+    r"\s*Py_ssize_t size;\s*PyTupleObject \*np;\s*PyObject \*\*dest;"
+    r"\s*PyObject \*\*dest_end;\s*if",
+    body,
+), "tuplerepeat: dest_end must be declared in the opening declaration block"
+assert len(re.findall(r"PyObject\s*\*\*dest_end\b", body)) == 1, (
+    "tuplerepeat: exactly one uninitialized dest_end declaration required"
+)
+assert re.search(
+    r"dest = np->ob_item;\s*dest_end = dest \+ size;",
+    body,
+), "tuplerepeat: assign dest_end immediately after dest at its original evaluation point"
+assert len(re.findall(r"\bdest_end\s*=", body)) == 1, (
+    "tuplerepeat: exactly one dest_end assignment required"
+)
+print("tuplerepeat dest_end C89 declaration and assignment order: PASS")