diff --git a/pytype/abstract/_classes.py b/pytype/abstract/_classes.py
index 5e7a68ff4..5b518a611 100644
--- a/pytype/abstract/_classes.py
+++ b/pytype/abstract/_classes.py
@@ -464,11 +464,15 @@ def _init_attr_metadata_from_pytd(self, decorator):
     # InitVar attributes to generate __init__, so the fields we want to add to
     # the subclass __init__ are the init params rather than the full list of
     # class attributes.
-    # We also need to use the list of class constants to restore names of the
-    # form `_foo`, which get replaced by `foo` in __init__.
     init = next(x for x in self.pytd_cls.methods if x.name == "__init__")
-    protected = {x.name[1:]: x.name for x in self.pytd_cls.constants
-                 if x.name.startswith("_")}
+    # attr strips the leading underscores off of fields when generating the
+    # __init__ argument for fields. This behavior may not be shared by other
+    # libraries, such as dataclasses.
+    if decorator.startswith("attr."):
+      protected = {x.name[1:]: x.name for x in self.pytd_cls.constants
+                   if x.name.startswith("_")}
+    else:
+      protected = {}
     params = []
     for p in init.signatures[0].params[1:]:
       if p.name in protected:
diff --git a/pytype/tests/test_abc2.py b/pytype/tests/test_abc2.py
index 959ce7396..ed96c464f 100644
--- a/pytype/tests/test_abc2.py
+++ b/pytype/tests/test_abc2.py
@@ -183,9 +183,9 @@ def test_abstract_property(self):
     errors = self.CheckWithErrors("""
       import abc
       class Foo(abc.ABC):
-        @abc.abstractmethod
+        @abc.abstractmethod  # wrong-arg-types[e]>=3.11
         @property
-        def f(self) -> str:  # wrong-arg-types[e]
+        def f(self) -> str:  # wrong-arg-types[e]<3.11
           return 'a'
 
         @property
diff --git a/pytype/tests/test_attr1.py b/pytype/tests/test_attr1.py
index 8dc776e4a..b49beedb7 100644
--- a/pytype/tests/test_attr1.py
+++ b/pytype/tests/test_attr1.py
@@ -152,12 +152,10 @@ def __init__(self, x: int, y: str) -> None: ...
     """)
 
   def test_type_clash(self):
-    # Note: explicitly inheriting from object keeps the line number of the error
-    # stable between Python versions.
     self.CheckWithErrors("""
       import attr
-      @attr.s
-      class Foo(object):  # invalid-annotation
+      @attr.s  # invalid-annotation>=3.11
+      class Foo:  # invalid-annotation<3.11
         x = attr.ib(type=str) # type: int
         y = attr.ib(type=str, default="")  # type: int
       Foo(x="")  # should not report an error
@@ -917,8 +915,8 @@ def int_attrib():
       self.CheckWithErrors("""
         import attr
         import foo
-        @attr.s()
-        class Foo(object):  # invalid-annotation
+        @attr.s()  # invalid-annotation>=3.11
+        class Foo:  # invalid-annotation<3.11
           x: int = foo.int_attrib()
       """, pythonpath=[d.path])
 
diff --git a/pytype/tests/test_attr2.py b/pytype/tests/test_attr2.py
index fecdcb37b..f6f9c13c0 100644
--- a/pytype/tests/test_attr2.py
+++ b/pytype/tests/test_attr2.py
@@ -289,12 +289,10 @@ def __init__(self, x: int, y: str) -> None: ...
     """)
 
   def test_type_clash(self):
-    # Note: explicitly inheriting from object keeps the line number of the error
-    # stable between Python versions.
     self.CheckWithErrors("""
       import attr
-      @attr.s
-      class Foo(object):  # invalid-annotation
+      @attr.s  # invalid-annotation>=3.11
+      class Foo:  # invalid-annotation<3.11
         x : int = attr.ib(type=str)
     """)
 
@@ -633,12 +631,10 @@ def __attrs_init__(self, x, y: int, z: str = "bar") -> None: ...
     """)
 
   def test_bad_default_param_order(self):
-    # Note: explicitly inheriting from object keeps the line number of the error
-    # stable between Python versions.
     self.CheckWithErrors("""
       import attr
-      @attr.s(auto_attribs=True)
-      class Foo(object):  # invalid-function-definition
+      @attr.s(auto_attribs=True)  # invalid-function-definition>=3.11
+      class Foo:  # invalid-function-definition<3.11
         x: int = 10
         y: str
     """)
diff --git a/pytype/tests/test_dataclasses.py b/pytype/tests/test_dataclasses.py
index 4c2624909..7a09cfbc1 100644
--- a/pytype/tests/test_dataclasses.py
+++ b/pytype/tests/test_dataclasses.py
@@ -231,12 +231,10 @@ def __init__(self, x: bool, y: int) -> None: ...
     """)
 
   def test_bad_default_param_order(self):
-    # Note: explicitly inheriting from object keeps the line number of the error
-    # stable between Python versions.
     self.CheckWithErrors("""
       import dataclasses
-      @dataclasses.dataclass()
-      class Foo(object):  # invalid-function-definition
+      @dataclasses.dataclass()  # invalid-function-definition>=3.11
+      class Foo:  # invalid-function-definition<3.11
         x: int = 10
         y: str
     """)
@@ -730,8 +728,8 @@ def test_sticky_kwonly_error(self):
     self.CheckWithErrors("""
       import dataclasses
 
-      @dataclasses.dataclass
-      class A():  # dataclass-error
+      @dataclasses.dataclass  # dataclass-error>=3.11
+      class A:  # dataclass-error<3.11
         a1: int
         _a: dataclasses.KW_ONLY
         a2: int = dataclasses.field(default_factory=lambda: 0)
@@ -802,6 +800,51 @@ class Test:
       dataclasses.replace(Test(), y=1, z=2)  # wrong-arg-types
     """)
 
+  def test_replace_late_annotation(self):
+    # Regression test: LateAnnotations (like `z: Z`) should behave
+    # like their underlying types once resolved. The dataclass overlay
+    # relies on this behavior.
+    self.Check("""
+      from __future__ import annotations
+      import dataclasses
+      @dataclasses.dataclass
+      class A:
+        z: Z
+        def do(self):
+          return dataclasses.replace(self.z, name="A")
+      @dataclasses.dataclass
+      class Z:
+        name: str
+    """)
+
+  def test_replace_as_method_with_kwargs(self):
+    # This is a weird case where replace is added as a method, then called
+    # with kwargs. This makes pytype unable to see that `self` is the object
+    # being modified, and also caused a crash when the dataclass overlay tries
+    # to unpack the object being modified from the args.
+    self.Check("""
+      import dataclasses
+      @dataclasses.dataclass
+      class WithKwargs:
+        replace = dataclasses.replace
+        def do(self, **kwargs):
+            return self.replace(**kwargs)
+    """)
+
+  def test_replace_subclass(self):
+    self.CheckWithErrors("""
+      import dataclasses
+      @dataclasses.dataclass
+      class Base:
+        name: str
+      @dataclasses.dataclass
+      class Sub(Base):
+        index: int
+      a = Sub(name="a", index=0)
+      dataclasses.replace(a, name="b", index=2)
+      dataclasses.replace(a, name="c", idx=3)  # wrong-keyword-args
+    """)
+
 
 class TestPyiDataclass(test_base.BaseTest):
   """Tests for @dataclasses in pyi files."""
@@ -1316,50 +1359,25 @@ def __init__(self, x: int) -> None: ...
         dataclasses.replace(x, y=1, z=2)  # wrong-keyword-args
       """)
 
-  def test_replace_late_annotation(self):
-    # Regression test: LateAnnotations (like `z: Z`) should behave
-    # like their underlying types once resolved. The dataclass overlay
-    # relies on this behavior.
-    self.Check("""
-      from __future__ import annotations
+  def test_no_name_mangling(self):
+    # attrs turns _x into x in `__init__`. We account for this in
+    # PytdClass._init_attr_metadata_from_pytd by replacing "x" with "_x" when
+    # reconstructing the class's attr metadata.
+    # However, dataclasses does *not* do this name mangling.
+    with self.DepTree([("foo.pyi", """
       import dataclasses
+      from typing import Annotated
       @dataclasses.dataclass
       class A:
-        z: Z
-        def do(self):
-          return dataclasses.replace(self.z, name="A")
-      @dataclasses.dataclass
-      class Z:
-        name: str
-    """)
-
-  def test_replace_as_method_with_kwargs(self):
-    # This is a weird case where replace is added as a method, then called
-    # with kwargs. This makes pytype unable to see that `self` is the object
-    # being modified, and also caused a crash when the dataclass overlay tries
-    # to unpack the object being modified from the args.
-    self.Check("""
-      import dataclasses
-      @dataclasses.dataclass
-      class WithKwargs:
-        replace = dataclasses.replace
-        def do(self, **kwargs):
-            return self.replace(**kwargs)
-    """)
-
-  def test_replace_subclass(self):
-    self.CheckWithErrors("""
-      import dataclasses
-      @dataclasses.dataclass
-      class Base:
-        name: str
-      @dataclasses.dataclass
-      class Sub(Base):
-        index: int
-      a = Sub(name="a", index=0)
-      dataclasses.replace(a, name="b", index=2)
-      dataclasses.replace(a, name="c", idx=3)  # wrong-keyword-args
-    """)
+          x: int
+          _x: Annotated[int, 'property']
+          def __init__(self, x: int) -> None: ...
+    """)]):
+      self.Check("""
+        import dataclasses
+        import foo
+        dataclasses.replace(foo.A(1), x=2)
+      """)
 
 
 if __name__ == "__main__":
diff --git a/pytype/tests/test_decorators2.py b/pytype/tests/test_decorators2.py
index 52c909c72..d06b9708f 100644
--- a/pytype/tests/test_decorators2.py
+++ b/pytype/tests/test_decorators2.py
@@ -235,9 +235,9 @@ class Decorate:
         def __call__(self, func):
           return func
       class Foo:
-        @classmethod
-        @Decorate  # forgot to instantiate Decorate
-        def bar(cls):  # wrong-arg-count[e]  # not-callable
+        @classmethod  # not-callable>=3.11
+        @Decorate  # forgot to instantiate Decorate  # wrong-arg-count[e]>=3.11
+        def bar(cls):  # wrong-arg-count[e]<3.11  # not-callable<3.11
           pass
       Foo.bar()
     """)
@@ -248,9 +248,9 @@ def test_uncallable_instance_as_decorator(self):
       class Decorate:
         pass  # forgot to define __call__
       class Foo:
-        @classmethod
-        @Decorate  # forgot to instantiate Decorate
-        def bar(cls):  # wrong-arg-count[e1]  # not-callable
+        @classmethod  # not-callable>=3.11
+        @Decorate  # forgot to instantiate Decorate  # wrong-arg-count[e1]>=3.11
+        def bar(cls):  # wrong-arg-count[e1]<3.11  # not-callable<3.11
           pass
       Foo.bar()
     """)
diff --git a/pytype/tests/test_final.py b/pytype/tests/test_final.py
index cdf1ca1a6..99b04be94 100644
--- a/pytype/tests/test_final.py
+++ b/pytype/tests/test_final.py
@@ -160,8 +160,8 @@ def f(self):
   def test_invalid(self):
     err = self.CheckWithErrors("""
       from typing_extensions import final
-      @final
-      def f(x):  # final-error[e]
+      @final  # final-error[e]>=3.11
+      def f(x):  # final-error[e]<3.11
         pass
     """)
     self.assertErrorSequences(err, {"e": ["Cannot apply @final", "f"]})
diff --git a/pytype/tests/test_methods1.py b/pytype/tests/test_methods1.py
index b47c3a1ad..b33753445 100644
--- a/pytype/tests/test_methods1.py
+++ b/pytype/tests/test_methods1.py
@@ -730,9 +730,9 @@ def test_invalid_classmethod(self):
       def f(x):
         return 42
       class A:
-        @classmethod
+        @classmethod  # not-callable[e]>=3.11
         @f
-        def myclassmethod(*args):  # not-callable[e]
+        def myclassmethod(*args):  # not-callable[e]<3.11
           return 3
     """)
     self.assertTypesMatchPytd(ty, """
diff --git a/pytype/tests/test_paramspec.py b/pytype/tests/test_paramspec.py
index f7abd5c79..03dcaf0c3 100644
--- a/pytype/tests/test_paramspec.py
+++ b/pytype/tests/test_paramspec.py
@@ -345,8 +345,8 @@ def g(a: int, b: str) -> int:
         def h(a: int, b: str) -> int:
           return 10
 
-        @foo.mismatched
-        def k(a: int, b: str) -> int:  # wrong-arg-types[e]
+        @foo.mismatched  # wrong-arg-types[e]>=3.11
+        def k(a: int, b: str) -> int:  # wrong-arg-types[e]<3.11
           return 10
       """)
     self.assertTypesMatchPytd(ty, """
diff --git a/pytype/vm.py b/pytype/vm.py
index 20b7044fc..2040ac49b 100644
--- a/pytype/vm.py
+++ b/pytype/vm.py
@@ -433,39 +433,11 @@ def simple_stack(self, opcode=None):
     else:
       return ()
 
-  def _in_3_11_decoration(self):
-    """Are we in a Python 3.11 decorator call?"""
-    if not (self.ctx.python_version == (3, 11) and
-            isinstance(self.current_opcode, opcodes.CALL) and
-            self.current_line in self._director.decorated_functions):
-      return False
-    prev = self.current_opcode
-    # Skip past the PRECALL opcode.
-    for _ in range(2):
-      prev = prev.prev
-      if not prev:
-        return False
-    # `prev` is the last loaded argument. For this call to be a decorator call,
-    # the last argument must be the decorated object or another decorator.
-    return (prev.line != self.current_line and
-            any(prev.line in d for d in (self._director.decorators,
-                                         self._director.decorated_functions)))
-
   def stack(self, func=None):
     """Get a frame stack for the given function for error reporting."""
     if (isinstance(func, abstract.INTERPRETER_FUNCTION_TYPES) and
         not self.current_opcode):
       return self.simple_stack(func.get_first_opcode())
-    elif self._in_3_11_decoration():
-      # TODO(b/241431224): In Python 3.10, the line number of the CALL opcode
-      # for a decorator is at the function definition line, while in 3.11, the
-      # opcode is at the decorator line. For a smoother transition from 3.10 to
-      # 3.11, we adjust the error line number for a bad decorator call to match
-      # 3.10. The 3.11 line number is more sensible, so we should stop making
-      # this adjustment once we're out of the transition period.
-      adjusted_opcode = self.current_opcode.at_line(
-          self._director.decorated_functions[self.current_line])
-      return self.simple_stack(adjusted_opcode)
     else:
       return self.frames