[clang] [Clang][Sema] Improve support for explicit specializations of constrained member functions & member function templates (PR #88963)

[Qizhi Hu via cfe-commits]

================
@@ -275,6 +275,13 @@ Response HandleFunction(Sema &SemaRef, const FunctionDecl *Function,
                                      TemplateArgs->asArray(),
                                      /*Final=*/false);
 
+    if (RelativeToPrimary &&
+        (Function->getTemplateSpecializationKind() ==
+             TSK_ExplicitSpecialization ||
----------------
jcsxky wrote:

This testcase runs OK before [be79079](https://github.com/llvm/llvm-project/pull/88963/commits/be79079507ffbd9b29683498f405dc2c32dd8ba7) applied and it may not be related to the condition `Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization`.

https://github.com/llvm/llvm-project/pull/88963