Revert "fix: fix literal with explicit widget type"

This reverts commit 35f35fe.

src/magicgui/type_map/_type_map.py

@@ -93,8 +93,14 @@ def match_type(type_: Any, default: Any | None = None) -> WidgetTuple | None:
         return widgets.FunctionGui, {"function": default}
 
     origin = get_origin(type_) or type_
-    choices, nullable = _literal_choices(type_)
-    if choices is not None:  # it's a Literal type
+    if origin is Literal:
+        choices = []
+        nullable = False
+        for choice in get_args(type_):
+            if choice is None:
+                nullable = True
+            else:
+                choices.append(choice)
         return widgets.ComboBox, {"choices": choices, "nullable": nullable}
 
     # sequence of paths
@@ -187,24 +193,6 @@ def _type_optional(
     return type_, nullable
 
 
-def _literal_choices(annotation: Any) -> tuple[list | None, bool]:
-    """Return choices and nullable for a Literal type.
-
-    if annotation is not a Literal type, returns (None, False)
-    """
-    origin = get_origin(annotation) or annotation
-    choices: list | None = None
-    nullable = False
-    if origin is Literal:
-        choices = []
-        for choice in get_args(annotation):
-            if choice is None:
-                nullable = True
-            else:
-                choices.append(choice)
-    return choices, nullable
-
-
 def _pick_widget_type(
     value: Any = Undefined,
     annotation: Any = Undefined,
@@ -231,10 +219,6 @@ def _pick_widget_type(
     _type, optional = _type_optional(value, annotation)
     options.setdefault("nullable", optional)
     choices = choices or (isinstance(_type, EnumMeta) and _type)
-    literal_choices, nullable = _literal_choices(annotation)
-    if literal_choices is not None:
-        choices = literal_choices
-        options["nullable"] = nullable
 
     if "widget_type" in options:
         widget_type = options.pop("widget_type")

tests/test_types.py

@@ -187,13 +187,3 @@ def test_type_registered_warns():
             register_type(Path, widget_type=widgets.TextEdit)
             assert isinstance(widgets.create_widget(annotation=Path), widgets.TextEdit)
     assert isinstance(widgets.create_widget(annotation=Path), widgets.FileEdit)
-
-
-def test_pick_widget_literal():
-    from typing import Literal
-
-    cls, options = type_map.get_widget_class(
-        annotation=Annotated[Literal["a", "b"], {"widget_type": "RadioButtons"}]
-    )
-    assert cls == widgets.RadioButtons
-    assert set(options["choices"]) == {"a", "b"}