[clang] [Clang] Remove explicit object from non member function. (PR #148807)

[Corentin Jabot via cfe-commits]

https://github.com/cor3ntin updated https://github.com/llvm/llvm-project/pull/148807

>From 25d5589b47b39779958c94011814cb68fd7ea374 Mon Sep 17 00:00:00 2001
From: Corentin Jabot <corentinjabot at gmail.com>
Date: Tue, 15 Jul 2025 11:06:03 +0200
Subject: [PATCH] [Clang] Remove explicit object from non member function.

To avoid crashing later (as we assume only member functions
can have explicit parameters)

Fixes #113185
---
 clang/docs/ReleaseNotes.rst                |  1 +
 clang/lib/Sema/SemaType.cpp                |  4 +++-
 clang/test/SemaCXX/cxx2b-deducing-this.cpp | 10 ++++++++++
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index e8c85483e9864..40213cd103c43 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -953,6 +953,7 @@ Bug Fixes to C++ Support
 - Fix a bug where private access specifier of overloaded function not respected. (#GH107629)
 - Correctly handles calling an explicit object member function template overload set
   through its address (``(&Foo::bar<baz>)()``).
+- Fix a crash when using an explicit object parameter in a non-member function. (#GH113185)
 - Fix a crash when forming an invalid call to an operator with an explicit object member. (#GH147121)
 - Correctly handle allocations in the condition of a ``if constexpr``.(#GH120197) (#GH134820)
 - Fixed a crash when handling invalid member using-declaration in C++20+ mode. (#GH63254)
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 661746731fdcc..bb114aff2366b 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -4860,7 +4860,9 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
             S.Diag(First->getBeginLoc(),
                    diag::err_explicit_object_parameter_invalid)
                 << First->getSourceRange();
-
+          // Do let non-member function have explicit parameters
+          // to not break assumptions elsewhere in the code.
+          First->setExplicitObjectParameterLoc(SourceLocation());
           D.setInvalidType();
           AreDeclaratorChunksValid = false;
         }
diff --git a/clang/test/SemaCXX/cxx2b-deducing-this.cpp b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
index 6987d0c020457..2253cbb26285e 100644
--- a/clang/test/SemaCXX/cxx2b-deducing-this.cpp
+++ b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
@@ -1347,3 +1347,13 @@ int main() {
     // expected-note@#S3-f-cand2 {{candidate function not viable: no known conversion from 'S3' to 'int' for object argument}}
 }
 }
+
+namespace GH113185 {
+
+void Bar(this int) { // expected-note {{candidate function}}
+    // expected-error at -1 {{an explicit object parameter cannot appear in a non-member function}}
+    Bar(0);
+    Bar(); // expected-error {{no matching function for call to 'Bar'}}
+}
+
+}