gh-87613: Reject deprecated parameters in AC VC

The generated vectorcall can skip the DeprecationWarning for
`/ [from X.Y]` and `* [from X.Y]` parameters, so report the combination
as unsupported, like optional groups.

Nothing in the tree uses these. They were used in a previous sqlite3
module migration (gh-93057, gh-108278).The last ones were removed in
2023 (gh-133595)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: cmaloney

Lib/test/test_clinic.py

@@ -3570,6 +3570,18 @@ class Foo "FooObject *" "Foo_Type"
         """
         self.expect_failure(block, err, lineno=7)
 
+    def test_vectorcall_with_deprecated_parameters(self):
+        err = "@vectorcall does not support deprecated parameters"
+        block = """
+            module m
+            class Foo "FooObject *" "Foo_Type"
+            @vectorcall
+            Foo.__init__
+                a: object = None
+                / [from 3.14]
+        """
+        self.expect_failure(block, err, lineno=5)
+
     def test_unused_param(self):
         block = self.parse("""
             module foo

Tools/clinic/libclinic/dsl_parser.py

@@ -1643,6 +1643,9 @@ def check_vectorcall_parameters(self, lineno: int) -> None:
             if p.group:
                 fail("@vectorcall does not support optional groups",
                      line_number=lineno)
+            if p.deprecated_positional or p.deprecated_keyword:
+                fail("@vectorcall does not support deprecated parameters",
+                     line_number=lineno)
             if p.is_vararg() or p.is_var_keyword():
                 continue
             if isinstance(p.converter, (self_converter,