diff --git a/pyproject.toml b/pyproject.toml
index cca732f6b..be86e48fc 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -141,8 +141,17 @@ show_column_numbers = true
 show_error_context = true
 strict_optional = true
 warn_redundant_casts = true
+warn_unused_configs = true
 warn_unused_ignores = true
 disallow_any_generics = true
+extra_checks = true
+enable_error_code = [
+    "type-arg",
+    "redundant-self",
+    "truthy-iterable",
+    "ignore-without-code",
+    "unused-awaitable",
+]
 
 [[tool.mypy.overrides]]
 module = [
diff --git a/sphinx/domains/__init__.py b/sphinx/domains/__init__.py
index 7c1122038..153e75111 100644
--- a/sphinx/domains/__init__.py
+++ b/sphinx/domains/__init__.py
@@ -93,7 +93,7 @@ class Index(ABC):
     shortname: str | None = None
 
     def __init__(self, domain: Domain) -> None:
-        if self.name is None or self.localname is None:
+        if not self.name or self.localname is None:
             raise SphinxError('Index subclass %s has no valid name or localname'
                               % self.__class__.__name__)
         self.domain = domain
diff --git a/sphinx/highlighting.py b/sphinx/highlighting.py
index 7e0d94a07..b4390ebc9 100644
--- a/sphinx/highlighting.py
+++ b/sphinx/highlighting.py
@@ -104,8 +104,8 @@ class PygmentsBridge:
             self.formatter = self.latex_formatter
             self.formatter_args['commandprefix'] = 'PYG'
 
-    def get_style(self, stylename: str) -> Style:
-        if stylename is None or stylename == 'sphinx':
+    def get_style(self, stylename: str) -> type[Style]:
+        if not stylename or stylename == 'sphinx':
             return SphinxStyle
         elif stylename == 'none':
             return NoneStyle
diff --git a/sphinx/transforms/post_transforms/images.py b/sphinx/transforms/post_transforms/images.py
index 561dcfc38..f98514f9c 100644
--- a/sphinx/transforms/post_transforms/images.py
+++ b/sphinx/transforms/post_transforms/images.py
@@ -47,7 +47,7 @@ class ImageDownloader(BaseImageConverter):
     default_priority = 100
 
     def match(self, node: nodes.image) -> bool:
-        if self.app.builder.supported_image_types == []:
+        if not self.app.builder.supported_image_types:
             return False
         if self.app.builder.supported_remote_images:
             return False
@@ -117,7 +117,7 @@ class DataURIExtractor(BaseImageConverter):
     default_priority = 150
 
     def match(self, node: nodes.image) -> bool:
-        if self.app.builder.supported_remote_images == []:
+        if not self.app.builder.supported_remote_images:
             return False
         if self.app.builder.supported_data_uri_images is True:
             return False
diff --git a/sphinx/util/nodes.py b/sphinx/util/nodes.py
index b68b7fdd4..f9ce975f9 100644
--- a/sphinx/util/nodes.py
+++ b/sphinx/util/nodes.py
@@ -220,7 +220,7 @@ def is_translatable(node: Node) -> bool:
             return False
         # <field_name>orphan</field_name>
         # XXX ignore all metadata (== docinfo)
-        if isinstance(node, nodes.field_name) and node.children[0] == 'orphan':
+        if isinstance(node, nodes.field_name) and (node.children[0] == 'orphan'):
             logger.debug('[i18n] SKIP %r because orphan node: %s',
                          get_full_module_name(node), repr_domxml(node))
             return False