Repository: python/mypy

Issue:
(🐞) `classmethod` on `TypedDict` leads to "AssertionError: fallback can't be filled out until semanal" with `--disallow-any-expr`
```py
from typing import TypedDict

class Foo(TypedDict):
    @classmethod  # E: AssertionError: fallback can't be filled out until semanal
    def baz(cls) -> "Foo": ...
```
This happens due to the `Any` expression (`no-any-expr`) trying to report an error.

- related: #5653
[playground](https://mypy-play.net/?mypy=master&python=3.10&flags=show-traceback%2Cstrict%2Cdisallow-any-expr&gist=1f6c96a1cff394ab2376cd3e769d5cf5)


Discussion:
Oops, I was supposed to raise this as crash
To be clear, this snippet only causes mypy to crash if the `--disallow-any-expr` option is enabled. If the option is not enabled, everything's fine. 
Yes, but who in their right mind would ever not have that enabled. Also it's enabled by default in basedmypy.
It's a legitimate crash report (and all crashes are v bad), I'm just laying out the steps needed to reproduce.
On master this doesn't crash, but gives a reasonable error
```
test.py:4: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
```
Oh, wait, I missed the flag.

Patch:
diff --git a/mypy/semanal_typeddict.py b/mypy/semanal_typeddict.py
--- a/mypy/semanal_typeddict.py
+++ b/mypy/semanal_typeddict.py
@@ -23,6 +23,7 @@
     NameExpr,
     PassStmt,
     RefExpr,
+    Statement,
     StrExpr,
     TempNode,
     TupleExpr,
@@ -93,7 +94,7 @@ def analyze_typeddict_classdef(self, defn: ClassDef) -> tuple[bool, TypeInfo | N
             and defn.base_type_exprs[0].fullname in TPDICT_NAMES
         ):
             # Building a new TypedDict
-            fields, types, required_keys = self.analyze_typeddict_classdef_fields(defn)
+            fields, types, statements, required_keys = self.analyze_typeddict_classdef_fields(defn)
             if fields is None:
                 return True, None  # Defer
             info = self.build_typeddict_typeinfo(
@@ -102,6 +103,7 @@ def analyze_typeddict_classdef(self, defn: ClassDef) -> tuple[bool, TypeInfo | N
             defn.analyzed = TypedDictExpr(info)
             defn.analyzed.line = defn.line
             defn.analyzed.column = defn.column
+            defn.defs.body = statements
             return True, info
 
         # Extending/merging existing TypedDicts
@@ -139,7 +141,12 @@ def analyze_typeddict_classdef(self, defn: ClassDef) -> tuple[bool, TypeInfo | N
         # Iterate over bases in reverse order so that leftmost base class' keys take precedence
         for base in reversed(typeddict_bases):
             self.add_keys_and_types_from_base(base, keys, types, required_keys, defn)
-        new_keys, new_types, new_required_keys = self.analyze_typeddict_classdef_fields(defn, keys)
+        (
+            new_keys,
+            new_types,
+            new_statements,
+            new_required_keys,
+        ) = self.analyze_typeddict_classdef_fields(defn, keys)
         if new_keys is None:
             return True, None  # Defer
         keys.extend(new_keys)
@@ -151,6 +158,7 @@ def analyze_typeddict_classdef(self, defn: ClassDef) -> tuple[bool, TypeInfo | N
         defn.analyzed = TypedDictExpr(info)
         defn.analyzed.line = defn.line
         defn.analyzed.column = defn.column
+        defn.defs.body = new_statements
         return True, info
 
     def add_keys_and_types_from_base(
@@ -250,7 +258,7 @@ def map_items_to_base(
 
     def analyze_typeddict_classdef_fields(
         self, defn: ClassDef, oldfields: list[str] | None = None
-    ) -> tuple[list[str] | None, list[Type], set[str]]:
+    ) -> tuple[list[str] | None, list[Type], list[Statement], set[str]]:
         """Analyze fields defined in a TypedDict class definition.
 
         This doesn't consider inherited fields (if any). Also consider totality,
@@ -259,17 +267,22 @@ def analyze_typeddict_classdef_fields(
         Return tuple with these items:
          * List of keys (or None if found an incomplete reference --> deferral)
          * List of types for each key
+         * List of statements from defn.defs.body that are legally allowed to be a
+           part of a TypedDict definition
          * Set of required keys
         """
         fields: list[str] = []
         types: list[Type] = []
+        statements: list[Statement] = []
         for stmt in defn.defs.body:
             if not isinstance(stmt, AssignmentStmt):
-                # Still allow pass or ... (for empty TypedDict's).
-                if not isinstance(stmt, PassStmt) and not (
+                # Still allow pass or ... (for empty TypedDict's) and docstrings
+                if isinstance(stmt, PassStmt) or (
                     isinstance(stmt, ExpressionStmt)
                     and isinstance(stmt.expr, (EllipsisExpr, StrExpr))
                 ):
+                    statements.append(stmt)
+                else:
                     self.fail(TPDICT_CLASS_ERROR, stmt)
             elif len(stmt.lvalues) > 1 or not isinstance(stmt.lvalues[0], NameExpr):
                 # An assignment, but an invalid one.
@@ -281,8 +294,9 @@ def analyze_typeddict_classdef_fields(
                 if name in fields:
                     self.fail(f'Duplicate TypedDict key "{name}"', stmt)
                     continue
-                # Append name and type in this case...
+                # Append stmt, name, and type in this case...
                 fields.append(name)
+                statements.append(stmt)
                 if stmt.type is None:
                     types.append(AnyType(TypeOfAny.unannotated))
                 else:
@@ -293,9 +307,9 @@ def analyze_typeddict_classdef_fields(
                         and not self.api.is_func_scope(),
                     )
                     if analyzed is None:
-                        return None, [], set()  # Need to defer
+                        return None, [], [], set()  # Need to defer
                     types.append(analyzed)
-                # ...despite possible minor failures that allow further analyzis.
+                # ...despite possible minor failures that allow further analysis.
                 if stmt.type is None or hasattr(stmt, "new_syntax") and not stmt.new_syntax:
                     self.fail(TPDICT_CLASS_ERROR, stmt)
                 elif not isinstance(stmt.rvalue, TempNode):
@@ -317,7 +331,7 @@ def analyze_typeddict_classdef_fields(
             t.item if isinstance(t, RequiredType) else t for t in types
         ]
 
-        return fields, types, required_keys
+        return fields, types, statements, required_keys
 
     def check_typeddict(
         self, node: Expression, var_name: str | None, is_func_scope: bool


Test patch:
diff --git a/test-data/unit/check-typeddict.test b/test-data/unit/check-typeddict.test
--- a/test-data/unit/check-typeddict.test
+++ b/test-data/unit/check-typeddict.test
@@ -221,6 +221,19 @@ reveal_type(d)  # N: Revealed type is "TypedDict('__main__.D', {'y': builtins.in
 [builtins fixtures/dict.pyi]
 [typing fixtures/typing-typeddict.pyi]
 
+[case testCannotCreateTypedDictWithDecoratedFunction]
+# flags: --disallow-any-expr
+# https://github.com/python/mypy/issues/13066
+from typing import TypedDict
+class D(TypedDict):
+    @classmethod  # E: Invalid statement in TypedDict definition; expected "field_name: field_type"
+    def m(self) -> D:
+        pass
+d = D()
+reveal_type(d)  # N: Revealed type is "TypedDict('__main__.D', {})"
+[builtins fixtures/dict.pyi]
+[typing fixtures/typing-typeddict.pyi]
+
 [case testTypedDictWithClassmethodAlternativeConstructorDoesNotCrash]
 # https://github.com/python/mypy/issues/5653
 from typing import TypedDict