[Clang] Fix a crash when incorrectly calling an explicit object member function template

[cor3ntin]

Fixes #75732

[llvmbot]

@llvm/pr-subscribers-clang

Author: cor3ntin (cor3ntin)

Changes

Fixes #75732

---

Full diff: https://github.com/llvm/llvm-project/pull/75913.diff

2 Files Affected:

• (modified) clang/lib/Sema/SemaExprMember.cpp (+2)
• (modified) clang/test/SemaCXX/cxx2b-deducing-this.cpp (+10)

diff --git a/clang/lib/Sema/SemaExprMember.cpp b/clang/lib/Sema/SemaExprMember.cpp
index 473eea55bb6b19..0e932a1436d6e0 100644
--- a/clang/lib/Sema/SemaExprMember.cpp
+++ b/clang/lib/Sema/SemaExprMember.cpp
@@ -253,6 +253,8 @@ static void diagnoseInstanceReference(Sema &SemaRef,
     SemaRef.Diag(Loc, diag::err_member_call_without_object)
         << Range << /*static*/ 0;
   else {
+    if (auto *Tpl = dyn_cast<FunctionTemplateDecl>(Rep))
+      Rep = Tpl->getTemplatedDecl();
     const auto *Callee = dyn_cast<CXXMethodDecl>(Rep);
     auto Diag = SemaRef.Diag(Loc, diag::err_member_call_without_object)
                 << Range << Callee->isExplicitObjectMemberFunction();
diff --git a/clang/test/SemaCXX/cxx2b-deducing-this.cpp b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
index 0033541fa322dc..aab35828096a8e 100644
--- a/clang/test/SemaCXX/cxx2b-deducing-this.cpp
+++ b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
@@ -626,3 +626,13 @@ void test() {
 }
 
 }
+
+
+namespace GH75732 {
+auto serialize(auto&& archive, auto&& c){ }
+struct D {
+    auto serialize(this auto&& self, auto&& archive) {
+        serialize(archive, self); // expected-error {{call to explicit member function without an object argument}}
+    }
+};
+}

[Fznamznon]

LGTM with a little NIT

[Fznamznon]

Perhaps a const can be added here.