Move a check out of --enable-nested-classes.

The --enable-nested-classes flag guards several related changes that generate
new type errors. This moves out one of the smaller changes (in terms of
breakage) from behind the flag. I've also sent out patches for the breakages.

PiperOrigin-RevId: 446018474

Author: rchen152

pytype/load_pytd.py

@@ -286,10 +286,9 @@ def log_module_not_found(self, module_name):
 class _Resolver:
   """Resolve symbols in a pytd tree."""
 
-  def __init__(self, builtins_ast, enable_nested_classes):
+  def __init__(self, builtins_ast):
     self.builtins_ast = builtins_ast
     self.allow_singletons = False
-    self._enable_nested_classes = enable_nested_classes
 
   def _lookup(self, visitor, mod_ast, lookup_ast):
     if lookup_ast:
@@ -298,9 +297,7 @@ def _lookup(self, visitor, mod_ast, lookup_ast):
     return mod_ast
 
   def resolve_local_types(self, mod_ast, *, lookup_ast=None):
-    local_lookup = visitors.LookupLocalTypes(
-        self.allow_singletons,
-        enable_nested_classes=self._enable_nested_classes)
+    local_lookup = visitors.LookupLocalTypes(self.allow_singletons)
     return self._lookup(local_lookup, mod_ast, lookup_ast)
 
   def resolve_builtin_types(self, mod_ast, *, lookup_ast=None):
@@ -376,7 +373,7 @@ def __init__(self, options, modules=None):
     self._path_finder = _PathFinder(options)
     self._builtin_loader = builtin_stubs.BuiltinLoader(
         parser.PyiOptions.from_toplevel_options(options))
-    self._resolver = _Resolver(self.builtins, options.enable_nested_classes)
+    self._resolver = _Resolver(self.builtins)
     self._import_name_cache = {}  # performance cache
     self._aliases = {}
     self._prefixes = set()

pytype/pytd/visitors.py

@@ -623,13 +623,11 @@ def VisitTypeDeclUnit(self, node):
 class LookupLocalTypes(_RemoveTypeParametersFromGenericAny, _ToTypeVisitor):
   """Look up local identifiers. Must be called on a TypeDeclUnit."""
 
-  def __init__(self, allow_singletons=False, toplevel=True,
-               enable_nested_classes=True):
+  def __init__(self, allow_singletons=False, toplevel=True):
     super().__init__(allow_singletons)
     self._toplevel = toplevel
     self.local_names = set()
     self.class_names = []
-    self._enable_nested_classes = enable_nested_classes
 
   def EnterTypeDeclUnit(self, unit):
     self.unit = unit
@@ -746,7 +744,7 @@ def VisitNamedType(self, node):
     return resolved_node
 
   def VisitClassType(self, t):
-    if not t.cls and self._enable_nested_classes:
+    if not t.cls:
       if t.name == self.class_names[-1]:
         full_name = ".".join(self.class_names)
         lookup_type = pytd.NamedType(full_name)