Revert "annotation_parens"

This reverts commit b6cd780453.

src/black/linegen.py

@@ -181,27 +181,30 @@ def visit_stmt(
 
     def visit_funcdef(self, node: Node) -> Iterator[Line]:
         """Visit function definition."""
-        yield from self.line()
+        if Preview.annotation_parens not in self.mode:
+            yield from self.visit_stmt(node, keywords={"def"}, parens=set())
+        else:
+            yield from self.line()
 
-        # Remove redundant brackets around return type annotation.
+            # Remove redundant brackets around return type annotation.
-        is_return_annotation = False
+            is_return_annotation = False
-        for child in node.children:
+            for child in node.children:
-            if child.type == token.RARROW:
+                if child.type == token.RARROW:
-                is_return_annotation = True
+                    is_return_annotation = True
-            elif is_return_annotation:
+                elif is_return_annotation:
-                if child.type == syms.atom and child.children[0].type == token.LPAR:
+                    if child.type == syms.atom and child.children[0].type == token.LPAR:
-                    if maybe_make_parens_invisible_in_atom(
+                        if maybe_make_parens_invisible_in_atom(
-                        child,
+                            child,
-                        parent=node,
+                            parent=node,
-                        remove_brackets_around_comma=False,
+                            remove_brackets_around_comma=False,
-                    ):
+                        ):
+                            wrap_in_parentheses(node, child, visible=False)
+                    else:
                         wrap_in_parentheses(node, child, visible=False)
-                else:
+                    is_return_annotation = False
-                    wrap_in_parentheses(node, child, visible=False)
-                is_return_annotation = False
 
-        for child in node.children:
+            for child in node.children:
-            yield from self.visit(child)
+                yield from self.visit(child)
 
     def visit_match_case(self, node: Node) -> Iterator[Line]:
         """Visit either a match or case statement."""

src/black/mode.py

@@ -149,6 +149,7 @@ def supports_feature(target_versions: Set[TargetVersion], feature: Feature) -> b
 class Preview(Enum):
     """Individual preview style features."""
 
+    annotation_parens = auto()
     long_docstring_quotes_on_newline = auto()
     string_processing = auto()