Do not allow TypedDict classes with extra keywords (#16438)

Author: sobolevn

mypy/messages.py

@@ -991,10 +991,17 @@ def maybe_note_about_special_args(self, callee: CallableType, context: Context)
                 context,
             )
 
+    def unexpected_keyword_argument_for_function(
+        self, for_func: str, name: str, context: Context, *, matches: list[str] | None = None
+    ) -> None:
+        msg = f'Unexpected keyword argument "{name}"' + for_func
+        if matches:
+            msg += f"; did you mean {pretty_seq(matches, 'or')}?"
+        self.fail(msg, context, code=codes.CALL_ARG)
+
     def unexpected_keyword_argument(
         self, callee: CallableType, name: str, arg_type: Type, context: Context
     ) -> None:
-        msg = f'Unexpected keyword argument "{name}"' + for_function(callee)
         # Suggest intended keyword, look for type match else fallback on any match.
         matching_type_args = []
         not_matching_type_args = []
@@ -1008,9 +1015,9 @@ def unexpected_keyword_argument(
         matches = best_matches(name, matching_type_args, n=3)
         if not matches:
             matches = best_matches(name, not_matching_type_args, n=3)
-        if matches:
-            msg += f"; did you mean {pretty_seq(matches, 'or')}?"
-        self.fail(msg, context, code=codes.CALL_ARG)
+        self.unexpected_keyword_argument_for_function(
+            for_function(callee), name, context, matches=matches
+        )
         module = find_defining_module(self.modules, callee)
         if module:
             assert callee.definition is not None

mypy/semanal_typeddict.py

@@ -323,6 +323,12 @@ def analyze_typeddict_classdef_fields(
         total: bool | None = True
         if "total" in defn.keywords:
             total = require_bool_literal_argument(self.api, defn.keywords["total"], "total", True)
+        if defn.keywords and defn.keywords.keys() != {"total"}:
+            for_function = ' for "__init_subclass__" of "TypedDict"'
+            for key in defn.keywords.keys():
+                if key == "total":
+                    continue
+                self.msg.unexpected_keyword_argument_for_function(for_function, key, defn)
         required_keys = {
             field
             for (field, t) in zip(fields, types)

test-data/unit/check-typeddict.test

@@ -3408,3 +3408,33 @@ B = TypedDict("B", {  # E: Type of a TypedDict key becomes "Any" due to an unfol
 })
 [builtins fixtures/dict.pyi]
 [typing fixtures/typing-typeddict.pyi]
+
+[case testTypedDictWithClassLevelKeywords]
+from typing import TypedDict, Generic, TypeVar
+
+T = TypeVar('T')
+
+class Meta(type): ...
+
+class WithMetaKeyword(TypedDict, metaclass=Meta):  # E: Unexpected keyword argument "metaclass" for "__init_subclass__" of "TypedDict"
+    ...
+
+class GenericWithMetaKeyword(TypedDict, Generic[T], metaclass=Meta):  # E: Unexpected keyword argument "metaclass" for "__init_subclass__" of "TypedDict"
+    ...
+
+# We still don't allow this, because the implementation is much easier
+# and it does not make any practical sense to do it:
+class WithTypeMeta(TypedDict, metaclass=type):  # E: Unexpected keyword argument "metaclass" for "__init_subclass__" of "TypedDict"
+    ...
+
+class OtherKeywords(TypedDict, a=1, b=2, c=3, total=True):  # E: Unexpected keyword argument "a" for "__init_subclass__" of "TypedDict" \
+                                                            # E: Unexpected keyword argument "b" for "__init_subclass__" of "TypedDict" \
+                                                            # E: Unexpected keyword argument "c" for "__init_subclass__" of "TypedDict"
+    ...
+
+class TotalInTheMiddle(TypedDict, a=1, total=True, b=2, c=3):  # E: Unexpected keyword argument "a" for "__init_subclass__" of "TypedDict" \
+                                                            # E: Unexpected keyword argument "b" for "__init_subclass__" of "TypedDict" \
+                                                            # E: Unexpected keyword argument "c" for "__init_subclass__" of "TypedDict"
+    ...
+[builtins fixtures/dict.pyi]
+[typing fixtures/typing-typeddict.pyi]