release note

Author: zmodem

clang/docs/ReleaseNotes.rst

@@ -497,6 +497,33 @@ Improvements to Clang's diagnostics
 - ``-Wreserved-identifier`` now fires on reserved parameter names in a function
   declaration which is not a definition.
 
+- ``-Wswitch`` will now diagnose unhandled enumerators in switches also when
+  the enumerator is deprecated. Warnings about using deprecated enumerators in
+  switch cases have moved behind a new ``-Wdeprecated-switch-case`` flag.
+
+  For example:
+
+  .. code-block:: c
+
+    enum E {
+      Red,
+      Green,
+      Blue [[deprecated]]
+    };
+    void example(enum E e) {
+      switch (e) {
+      case Red:   // stuff...
+      case Green: // stuff...
+      }
+    }
+
+  will result in a warning about ``Blue`` not being handled in the switch.
+
+  The warning can be fixed either by adding a ``default:``, or by adding
+  ``case Blue:``. Since the enumerator is deprecated, the latter approach will
+  trigger a ``'Blue' is deprecated`` warning, which can be turned off with
+  ``-Wno-deprecated-switch-case``.
+
 Improvements to Clang's time-trace
 ----------------------------------