Remove -Wweak-template-vtables

as it was planned for removal in clang 15 and we're now past the branch point

See llvm/llvm-project#19107

Differential revision: https://reviews.llvm.org/D118762

Author: zmodem

clang/docs/ReleaseNotes.rst

@@ -67,6 +67,9 @@ Modified Compiler Flags
 Removed Compiler Flags
 -------------------------
 
+- -Wweak-template-vtables, which was deprecated in the previous release and no
+  longer had any effect, has been removed.
+
 New Pragmas in Clang
 --------------------
 

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -1651,9 +1651,6 @@ def warn_weak_vtable : Warning<
   "%0 has no out-of-line virtual method definitions; its vtable will be "
   "emitted in every translation unit">,
   InGroup<DiagGroup<"weak-vtables">>, DefaultIgnore;
-def warn_weak_template_vtable : Warning<
-  "this warning is no longer in use and will be removed in the next release">,
-  InGroup<DiagGroup<"weak-template-vtables">>, DefaultIgnore;
 
 def ext_using_undefined_std : ExtWarn<
   "using directive refers to implicitly-defined namespace 'std'">;

clang/test/SemaCXX/warn-weak-vtables.cpp

@@ -3,9 +3,6 @@
 // Check that this warning is disabled on MS ABI targets which don't have key
 // functions.
 // RUN: %clang_cc1 %s -fsyntax-only -triple %ms_abi_triple -Werror -Wweak-vtables
-//
-// -Wweak-template-vtables is deprecated but we still parse it.
-// RUN: %clang_cc1 %s -fsyntax-only -Werror -Wweak-template-vtables
 
 struct A { // expected-warning {{'A' has no out-of-line virtual method definitions; its vtable will be emitted in every translation unit}}
   virtual void f() { }