[clang] [Clang] Fix a regression introduced by #147046 (PR #150893)

[Corentin Jabot via cfe-commits]

https://github.com/cor3ntin updated https://github.com/llvm/llvm-project/pull/150893

>From 8af7ce05012ca6e0047fc452196befc056eadf40 Mon Sep 17 00:00:00 2001
From: Corentin Jabot <corentinjabot at gmail.com>
Date: Mon, 28 Jul 2025 09:20:28 +0200
Subject: [PATCH] [Clang] Fix a regression introduced by #147046

Static functions have an implicit object argument during deduction,
---
 clang/lib/Sema/SemaOverload.cpp            |  4 +--
 clang/test/SemaCXX/cxx2b-deducing-this.cpp | 32 ++++++++++++++++++++++
 2 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 5dd5b495480d9..76e189d536849 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -8042,8 +8042,8 @@ static void AddTemplateOverloadCandidateImmediately(
 
     Candidate.IgnoreObjectArgument =
         isa<CXXMethodDecl>(Candidate.Function) &&
-        cast<CXXMethodDecl>(Candidate.Function)
-            ->isImplicitObjectMemberFunction() &&
+        !cast<CXXMethodDecl>(Candidate.Function)
+             ->isExplicitObjectMemberFunction() &&
         !isa<CXXConstructorDecl>(Candidate.Function);
 
     Candidate.ExplicitCallArguments = Args.size();
diff --git a/clang/test/SemaCXX/cxx2b-deducing-this.cpp b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
index 2253cbb26285e..fcbe0f62e6d4f 100644
--- a/clang/test/SemaCXX/cxx2b-deducing-this.cpp
+++ b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
@@ -1357,3 +1357,35 @@ void Bar(this int) { // expected-note {{candidate function}}
 }
 
 }
+
+namespace GH147046_regression {
+
+template <typename z> struct ai {
+    ai(z::ah);
+};
+
+template <typename z> struct ak {
+    template <typename am> void an(am, z);
+    template <typename am> static void an(am, ai<z>);
+};
+template <typename> struct ao {};
+
+template <typename ap>
+auto ar(ao<ap> at) -> decltype(ak<ap>::an(at, 0));
+// expected-note at -1 {{candidate template ignored: substitution failure [with ap = GH147046_regression::ay]: no matching function for call to 'an'}}
+
+class aw;
+struct ax {
+    typedef int ah;
+};
+struct ay {
+    typedef aw ah;
+};
+
+ao<ay> az ;
+ai<ax> bd(0);
+void f() {
+    ar(az); // expected-error {{no matching function for call to 'ar'}}
+}
+
+}