mypy: Enable redundant-expr errors.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

pyproject.toml

@@ -24,6 +24,11 @@ disallow_untyped_calls = false
 disallow_untyped_decorators = false
 warn_return_any = false
 
+# Enable optional errors.
+enable_error_code = [
+    "redundant-expr",
+]
+
 # Display the codes needed for # type: ignore[code] annotations.
 show_error_codes = true
 

tools/lib/capitalization.py

@@ -218,7 +218,7 @@ def check_capitalization(strings: List[str]) -> Tuple[List[str], List[str], List
         capitalized = is_capitalized(safe_text)
         if not capitalized:
             errors.append(text)
-        elif capitalized and has_ignored_phrase:
+        elif has_ignored_phrase:
             ignored.append(text)
 
         banned_word_errors.extend(check_banned_words(text))

tools/lib/template_parser.py

@@ -464,7 +464,7 @@ def validate(fn: Optional[str] = None, text: Optional[str] = None) -> List[Token
                         f"Tag must be self-closing: {tag} at {fn} line {token.line}, col {token.col}"
                     )
             elif kind == "html_singleton":
-                if not state.foreign and tag not in HTML_VOID_TAGS:
+                if tag not in HTML_VOID_TAGS:
                     raise TemplateParserException(
                         f"Tag must not be self-closing: {tag} at {fn} line {token.line}, col {token.col}"
                     )

zerver/lib/mention.py

@@ -87,7 +87,6 @@ class MentionBackend:
             # We expect callers who take advantage of our cache to supply both
             # id and full_name in the user mentions in their messages.
             for user in user_list:
-                if user.id is not None and user.full_name is not None:
                 self.user_cache[(user.id, user.full_name)] = user
 
             result += user_list

zerver/lib/scim.py

@@ -181,7 +181,7 @@ class ZulipSCIMUser(SCIMUser):
             self._full_name_new_value = new_value
 
     def change_is_active(self, new_value: bool) -> None:
-        if new_value is not None and new_value != self.obj.is_active:
+        if new_value != self.obj.is_active:
             self._is_active_new_value = new_value
 
     def handle_replace(

zerver/lib/webhooks/common.py

@@ -114,7 +114,7 @@ def check_send_webhook_message(
         # double escape their URLs in a manner that escaped space characters
         # (%20) are never properly decoded. We work around that by making sure
         # that the URL parameters are decoded on our end.
-        if stream is not None and unquote_url_parameters:
+        if unquote_url_parameters:
             stream = unquote(stream)
 
         if user_specified_topic is not None: