diff --git a/setup.cfg b/setup.cfg
index 091b59bbd..5b4753c5d 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -31,7 +31,7 @@ directory = sphinx/locale/
 
 [flake8]
 max-line-length = 95
-ignore = E116,E241,E251,E741,I101
+ignore = E116,E241,E251,E741,W504,I101
 exclude = .git,.tox,.venv,tests/*,build/*,doc/_build/*,sphinx/search/*,doc/ext/example*.py
 application-import-names = sphinx
 import-order-style = smarkets
diff --git a/sphinx/builders/linkcheck.py b/sphinx/builders/linkcheck.py
index 8a10a4f2c..312a26252 100644
--- a/sphinx/builders/linkcheck.py
+++ b/sphinx/builders/linkcheck.py
@@ -158,7 +158,7 @@ class CheckExternalLinksBuilder(Builder):
                         # the server and the network
                         response = requests.head(req_url, config=self.app.config, **kwargs)
                         response.raise_for_status()
-                    except HTTPError as err:
+                    except HTTPError:
                         # retry with GET request if that fails, some servers
                         # don't like HEAD requests.
                         response = requests.get(req_url, stream=True, config=self.app.config,
diff --git a/sphinx/directives/other.py b/sphinx/directives/other.py
index e9a3864ab..014bcc2d8 100644
--- a/sphinx/directives/other.py
+++ b/sphinx/directives/other.py
@@ -29,7 +29,7 @@ if False:
     from sphinx.application import Sphinx  # NOQA
 
 
-glob_re = re.compile('.*[*?\[].*')
+glob_re = re.compile(r'.*[*?\[].*')
 
 
 def int_or_nothing(argument):
diff --git a/sphinx/ext/autosummary/generate.py b/sphinx/ext/autosummary/generate.py
index 0c83a4e25..dbf43d4c8 100644
--- a/sphinx/ext/autosummary/generate.py
+++ b/sphinx/ext/autosummary/generate.py
@@ -263,7 +263,7 @@ def find_autosummary_in_docstring(name, module=None, filename=None):
         pass
     except ImportError as e:
         print("Failed to import '%s': %s" % (name, e))
-    except SystemExit as e:
+    except SystemExit:
         print("Failed to import '%s'; the module executes module level "
               "statement and it might call sys.exit()." % name)
     return []
diff --git a/sphinx/writers/latex.py b/sphinx/writers/latex.py
index f10b918bd..22304ded4 100644
--- a/sphinx/writers/latex.py
+++ b/sphinx/writers/latex.py
@@ -235,7 +235,7 @@ class ExtBabel(Babel):
 
     def get_mainlanguage_options(self):
         # type: () -> unicode
-        """Return options for polyglossia's ``\setmainlanguage``."""
+        """Return options for polyglossia's ``\\setmainlanguage``."""
         language = super(ExtBabel, self).get_language()
         if self.use_polyglossia is False:
             return None