[C2y] Implement WG14 N3622 static used in an inline

clang/docs/ReleaseNotes.rst

@@ -180,6 +180,9 @@ C Language Changes
 
 C2y Feature Support
 ^^^^^^^^^^^^^^^^^^^
+- No longer triggering ``-Wstatic-in-inline`` in C2y mode; use of a static
+  function or variable within an extern inline function is no longer a
+  constraint per `WG14 N3622 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3622.txt>`_.
 - Clang now supports `N3355 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3355.htm>`_ Named Loops.
 
 C23 Feature Support

clang/lib/Sema/SemaExpr.cpp

@@ -166,7 +166,11 @@ static void diagnoseUseOfInternalDeclInInlineFunction(Sema &S,
   // This is disabled under C++; there are too many ways for this to fire in
   // contexts where the warning is a false positive, or where it is technically
   // correct but benign.
-  if (S.getLangOpts().CPlusPlus)
+  //
+  // This is also disabled in C2y because of WG14 N3622 which removed the
+  // constraint entirely. It is left enabled in earlier language modes because
+  // this is a constraint in those language modes.
+  if (S.getLangOpts().CPlusPlus || S.getLangOpts().C2y)
     return;
 
   // Check if this is an inlined function or method.

clang/test/C/C2y/n3622.c

@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -verify=good -pedantic -Wall -std=c2y %s
+// RUN: %clang_cc1 -verify -pedantic -Wall -std=c23 %s
+// RUN: %clang_cc1 -verify -pedantic -Wall -std=c17 %s
+// good-no-diagnostics
+
+/* WG14 N3622: Clang 22
+ * Allow calling static inline within extern inline
+ *
+ * This verifies that a constraint from previous standards is no longer
+ * triggered in C2y mode. The constraint is with calling a statric function
+ * or using a static variable from an inline function with external linkage.
+ */
+
+static void static_func(void) {} // expected-note {{declared here}}
+static int static_var;           // expected-note {{declared here}}
+
+extern inline void test(void) {
+  static_func();   // expected-warning {{static function 'static_func' is used in an inline function with external linkage}}
+  static_var = 12; // expected-warning {{static variable 'static_var' is used in an inline function with external linkage}}
+}

clang/www/c_status.html

@@ -349,7 +349,7 @@ <h2 id="c2y">C2y implementation status</h2>
     <tr>
       <td>Allow calling static inline within extern inline</td>
       <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3622.txt">N3622</a></td>
-      <td class="unknown" align="center">Unknown</td>
+      <td class="unreleased" align="center">Clang 22</td>
 	</tr>
     <tr>
       <td>Generic replacement (v. 2 of quasi-literals)</td>