Do not blindly undefer on leaving fuction

Author: ilevkivskyi

mypy/checker.py

@@ -1110,6 +1110,7 @@ def check_func_item(
         """
         self.dynamic_funcs.append(defn.is_dynamic() and not type_override)
 
+        enclosing_node_deferred = self.current_node_deferred
         with self.enter_partial_types(is_function=True):
             typ = self.function_type(defn)
             if type_override:
@@ -1121,7 +1122,7 @@ def check_func_item(
                 raise RuntimeError("Not supported")
 
         self.dynamic_funcs.pop()
-        self.current_node_deferred = False
+        self.current_node_deferred = enclosing_node_deferred
 
         if name == "__exit__":
             self.check__exit__return_type(defn)

test-data/unit/check-inference.test

@@ -3913,3 +3913,21 @@ x = "abc"
 for x in list[int]():
     reveal_type(x)  # N: Revealed type is "builtins.int"
 reveal_type(x) # N: Revealed type is "Union[builtins.int, builtins.str]"
+
+[case testVariableDeferredWithNestedFunction]
+from typing import Callable, TypeVar
+
+T = TypeVar("T")
+def deco(fn: Callable[[], T]) -> Callable[[], T]: ...
+
+@deco
+def f() -> None:
+    x = 1
+    f()  # defer current node
+    x = x
+
+    def nested() -> None:
+        ...
+
+    # The type below should not be Any.
+    reveal_type(x)  # N: Revealed type is "builtins.int"