Support namedtuple.__replace__ in Python 3.13 (#17259)

Author: hauntsaninja

mypy/semanal_namedtuple.py

@@ -623,6 +623,12 @@ def add_method(
             ret=selftype,
             args=[Argument(var, var.type, EllipsisExpr(), ARG_NAMED_OPT) for var in vars],
         )
+        if self.options.python_version >= (3, 13):
+            add_method(
+                "__replace__",
+                ret=selftype,
+                args=[Argument(var, var.type, EllipsisExpr(), ARG_NAMED_OPT) for var in vars],
+            )
 
         def make_init_arg(var: Var) -> Argument:
             default = default_items.get(var.name, None)

test-data/unit/check-namedtuple.test

@@ -1398,3 +1398,17 @@ class Test3(NamedTuple, metaclass=type):  # E: Unexpected keyword argument "meta
     ...
 [builtins fixtures/tuple.pyi]
 [typing fixtures/typing-namedtuple.pyi]
+
+
+[case testNamedTupleDunderReplace]
+# flags: --python-version 3.13
+from typing import NamedTuple
+
+class A(NamedTuple):
+    x: int
+
+A(x=0).__replace__(x=1)
+A(x=0).__replace__(x="asdf")  # E: Argument "x" to "__replace__" of "A" has incompatible type "str"; expected "int"
+A(x=0).__replace__(y=1)  # E: Unexpected keyword argument "y" for "__replace__" of "A"
+[builtins fixtures/tuple.pyi]
+[typing fixtures/typing-namedtuple.pyi]