Minor updates

JukkaL · JukkaL · commit 5a41b0e994e8 · 2026-04-21T17:51:38.000+01:00
diff --git a/mypy/checker.py b/mypy/checker.py
@@ -425,7 +425,7 @@ class TypeChecker(NodeVisitor[None], TypeCheckerSharedApi, SplittingVisitor):
     # NOTE: The names might not be unique, they are only for debugging purposes.
     widened_vars: list[str]
     # Global variables widened inside a function body, to be propagated to
-    # the module-level binder after the function is type checked.
+    # the module-level binder after the function is type checked (with --allow-redefinition-new).
     _globals_widened_in_func: list[tuple[NameExpr, Type]]
     globals: SymbolTable
     modules: dict[str, MypyFile]
@@ -4964,7 +4964,7 @@ def can_widen_in_scope(self, name: NameExpr, orig_type: Type) -> bool:
         """Can a variable type be widened via assignment in the current scope?
 
         Globals can only be widened from within a function if the original type
-        is None (backward compat with partial type handling of ``x = None``).
+        is None (backward compat with partial type handling of `x = None`).
         """
         if (
             name.kind == GDEF
@@ -8372,6 +8372,7 @@ def visit_nonlocal_decl(self, o: NonlocalDecl, /) -> None:
 
     def visit_global_decl(self, o: GlobalDecl, /) -> None:
         if self.options.allow_redefinition_new:
+            # Add names to binder, since their types could be widened
             for name in o.names:
                 sym = self.globals.get(name)
                 if sym and isinstance(sym.node, Var) and sym.node.type is not None:
diff --git a/test-data/unit/fine-grained.test b/test-data/unit/fine-grained.test
@@ -11736,3 +11736,29 @@ def bar() -> str: return "a"
 main:2: note: Revealed type is "None | builtins.int"
 ==
 main:2: note: Revealed type is "None | builtins.str"
+
+[case testGlobalNoneWidenedInFuncWithRedefinition3]
+import m
+reveal_type(m.x)
+
+[file m.py]
+# mypy: allow-redefinition-new
+import m2
+
+x = None
+
+def foo() -> None:
+    def nested(self) -> None:
+        global x
+        x = m2.bar()
+
+[file m2.py]
+def bar() -> int: return 0
+
+[file m2.py.2]
+def bar() -> str: return "a"
+
+[out]
+main:2: note: Revealed type is "None | builtins.int"
+==
+main:2: note: Revealed type is "None | builtins.str"
