[Clang] Don't allow implicit this access when checking function constraints

clang/lib/Sema/SemaConcept.cpp

@@ -1105,10 +1105,6 @@ static bool CheckFunctionConstraintsWithoutInstantiation(
   }
 
   Sema::ContextRAII SavedContext(SemaRef, FD);
-  std::optional<Sema::CXXThisScopeRAII> ThisScope;
-  if (auto *Method = dyn_cast<CXXMethodDecl>(FD))
-    ThisScope.emplace(SemaRef, /*Record=*/Method->getParent(),
-                      /*ThisQuals=*/Method->getMethodQualifiers());
   return SemaRef.CheckConstraintSatisfaction(
       Template, TemplateAC, MLTAL, PointOfInstantiation, Satisfaction);
 }

clang/lib/Sema/SemaTemplate.cpp

@@ -4749,8 +4749,6 @@ Sema::CheckConceptTemplateId(const CXXScopeSpec &SS,
   EnterExpressionEvaluationContext EECtx{
       *this, ExpressionEvaluationContext::Unevaluated, CSD};
 
-  ContextRAII CurContext(*this, CSD->getDeclContext(),
-                         /*NewThisContext=*/false);
   if (!AreArgsDependent &&
       CheckConstraintSatisfaction(
           NamedConcept, AssociatedConstraint(NamedConcept->getConstraintExpr()),

clang/test/SemaTemplate/concepts.cpp

@@ -1228,26 +1228,26 @@ template <KnownKind T> struct KnownType {
 
 }
 
-namespace GH115838 {
+namespace CWG2369_Regression_2 {
 
-template<typename T> concept has_x = requires(T t) {{ t.x };};
-
-class Publ { public:    int x = 0; };
-class Priv { private:   int x = 0; };
-class Prot { protected: int x = 0; };
-class Same { protected: int x = 0; };
-
-template<typename T> class D;
-template<typename T> requires ( has_x<T>) class D<T>: public T { public: static constexpr bool has = 1; };
-template<typename T> requires (!has_x<T>) class D<T>: public T { public: static constexpr bool has = 0; };
+template <typename T>
+concept HasFastPropertyForAttribute =
+    requires(T element, int name) { element.propertyForAttribute(name); };
+
+template <typename OwnerType>
+struct SVGPropertyOwnerRegistry {
+  static int fastAnimatedPropertyLookup() {
+    static_assert (HasFastPropertyForAttribute<OwnerType>);
+    return 1;
+  }
+};
 
-// "Same" is identical to "Prot" but queried before used.
-static_assert(!has_x<Same>,  "Protected should be invisible.");
-static_assert(!D<Same>::has, "Protected should be invisible.");
+class SVGCircleElement {
+  friend SVGPropertyOwnerRegistry<SVGCircleElement>;
+  void propertyForAttribute(int);
+};
 
-static_assert( D<Publ>::has, "Public should be visible.");
-static_assert(!D<Priv>::has, "Private should be invisible.");
-static_assert(!D<Prot>::has, "Protected should be invisible.");
+int i = SVGPropertyOwnerRegistry<SVGCircleElement>::fastAnimatedPropertyLookup();
 
 }