[Clang] fix overload resolution for object parameters with top-level cv-qualifiers in member functions

[a-tarasyuk]

Fixes #100394

[llvmbot]

@llvm/pr-subscribers-clang

Author: Oleksandr T. (a-tarasyuk)

Changes

Fixes #100394

---

Full diff: https://github.com/llvm/llvm-project/pull/110435.diff

3 Files Affected:

• (modified) clang/docs/ReleaseNotes.rst (+1)
• (modified) clang/lib/Sema/SemaOverload.cpp (+3)
• (modified) clang/test/SemaCXX/cxx2b-deducing-this.cpp (+7)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 28c759538f7df6..1bec2838765dab 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -447,6 +447,7 @@ Bug Fixes to C++ Support
 - Fixed an assertion failure in debug mode, and potential crashes in release mode, when
   diagnosing a failed cast caused indirectly by a failed implicit conversion to the type of the constructor parameter.
 - Fixed an assertion failure by adjusting integral to boolean vector conversions (#GH108326)
+- Fixed overload handling for object parameters with top-level cv-qualifiers in explicit member functions (#GH100394)
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 0c1e054f7c30a4..7c40bab70bbe9d 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -1511,6 +1511,9 @@ static bool IsOverloadOrOverrideImpl(Sema &SemaRef, FunctionDecl *New,
       auto NewObjectType = New->getFunctionObjectParameterReferenceType();
       auto OldObjectType = Old->getFunctionObjectParameterReferenceType();
 
+      if (NewObjectType.isConstQualified() != OldObjectType.isConstQualified())
+        return false;
+
       auto IsImplicitWithNoRefQual = [](const CXXMethodDecl *F) {
         return F->getRefQualifier() == RQ_None &&
                !F->isExplicitObjectMemberFunction();
diff --git a/clang/test/SemaCXX/cxx2b-deducing-this.cpp b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
index 63bf92e8d5edd3..5fd02502ce6df4 100644
--- a/clang/test/SemaCXX/cxx2b-deducing-this.cpp
+++ b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
@@ -1073,3 +1073,10 @@ int main() {
   return foo[]; // expected-error {{no viable overloaded operator[] for type 'Foo'}}
 }
 }
+
+namespace GH100394 {
+struct C {
+  void f(this const C);
+  void f() const ;      // ok
+};
+}

[cor3ntin]

do we care about __restrict @AaronBallman ?

[erichkeane]

The always-early-return doesn't make sense here to me, as Corentin mentioned, because __restrict can't be overloaded on IIRC.