lib.enum: rename EnumMeta to EnumType.

Fixes #1073.

amaranth/lib/enum.py

@@ -14,14 +14,14 @@ for _member in py_enum.__all__:
 del _member
 
 
-class EnumMeta(ShapeCastable, py_enum.EnumMeta):
-    """Subclass of the standard :class:`enum.EnumMeta` that implements the :class:`ShapeCastable`
+class EnumType(ShapeCastable, py_enum.EnumMeta):
+    """Subclass of the standard :class:`enum.EnumType` that implements the :class:`ShapeCastable`
     protocol.
 
     This metaclass provides the :meth:`as_shape` method, making its instances
     :ref:`shape-like <lang-shapelike>`, and accepts a ``shape=`` keyword argument
     to specify a shape explicitly. Other than this, it acts the same as the standard
-    :class:`enum.EnumMeta` class; if the ``shape=`` argument is not specified and
+    :class:`enum.EnumType` class; if the ``shape=`` argument is not specified and
     :meth:`as_shape` is never called, it places no restrictions on the enumeration class
     or the values of its members.
 
@@ -180,32 +180,37 @@ class EnumMeta(ShapeCastable, py_enum.EnumMeta):
         yield Repr(FormatEnum(cls), value)
 
 
+# In 3.11, Python renamed EnumMeta to EnumType. Like Python itself, we support both for
+# compatibility.
+EnumMeta = EnumType
+
+
 class Enum(py_enum.Enum):
-    """Subclass of the standard :class:`enum.Enum` that has :class:`EnumMeta` as
+    """Subclass of the standard :class:`enum.Enum` that has :class:`EnumType` as
     its metaclass and :class:`EnumView` as its view class."""
 
 
 class IntEnum(py_enum.IntEnum):
-    """Subclass of the standard :class:`enum.IntEnum` that has :class:`EnumMeta` as
+    """Subclass of the standard :class:`enum.IntEnum` that has :class:`EnumType` as
     its metaclass."""
 
 
 class Flag(py_enum.Flag):
-    """Subclass of the standard :class:`enum.Flag` that has :class:`EnumMeta` as
+    """Subclass of the standard :class:`enum.Flag` that has :class:`EnumType` as
     its metaclass and :class:`FlagView` as its view class."""
 
 
 class IntFlag(py_enum.IntFlag):
-    """Subclass of the standard :class:`enum.IntFlag` that has :class:`EnumMeta` as
+    """Subclass of the standard :class:`enum.IntFlag` that has :class:`EnumType` as
     its metaclass."""
 
 
 # Fix up the metaclass after the fact: the metaclass __new__ requires these classes
 # to already be present, and also would not install itself on them due to lack of shape.
-Enum.__class__ = EnumMeta
-IntEnum.__class__ = EnumMeta
-Flag.__class__ = EnumMeta
-IntFlag.__class__ = EnumMeta
+Enum.__class__ = EnumType
+IntEnum.__class__ = EnumType
+Flag.__class__ = EnumType
+IntFlag.__class__ = EnumType
 
 
 class EnumView(ValueCastable):
@@ -219,7 +224,7 @@ class EnumView(ValueCastable):
         """Constructs a view with the given enum type and target
         (a :ref:`value-like <lang-valuelike>`).
         """
-        if not isinstance(enum, EnumMeta) or not hasattr(enum, "_amaranth_shape_"):
+        if not isinstance(enum, EnumType) or not hasattr(enum, "_amaranth_shape_"):
             raise TypeError(f"EnumView type must be an enum with shape, not {enum!r}")
         try:
             cast_target = Value.cast(target)