[Clang][Sema] Fix issue on requires expression with templated base class member function (#85198)

Fix #84020
Skip checking implicit object parameter in the context of
`RequiresExprBodyDecl`.

Co-authored-by: huqizhi <[email protected]>

Author: jcsxky

clang/docs/ReleaseNotes.rst

@@ -538,6 +538,7 @@ Bug Fixes to C++ Support
   object parameter.
   Fixes (#GH70604), (#GH79754), (#GH84163), (#GH84425), (#GH86054), (#GH86398), and (#GH86399).
 - Fix a crash when deducing ``auto`` from an invalid dereference (#GH88329).
+- Fix a crash in requires expression with templated base class member function. Fixes (#GH84020).
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^

clang/lib/Sema/SemaExpr.cpp

@@ -7739,7 +7739,8 @@ ExprResult Sema::BuildResolvedCallExpr(Expr *Fn, NamedDecl *NDecl,
   }
 
   if (CXXMethodDecl *Method = dyn_cast_or_null<CXXMethodDecl>(FDecl))
-    if (Method->isImplicitObjectMemberFunction())
+    if (!isa<RequiresExprBodyDecl>(CurContext) &&
+        Method->isImplicitObjectMemberFunction())
       return ExprError(Diag(LParenLoc, diag::err_member_call_without_object)
                        << Fn->getSourceRange() << 0);
 

clang/test/SemaCXX/PR84020.cpp

@@ -0,0 +1,23 @@
+// RUN: %clang_cc1 -std=c++20 -verify %s
+// RUN: %clang_cc1 -std=c++23 -verify %s
+// expected-no-diagnostics
+
+struct B {
+    template <typename S>
+    void foo();
+
+    void bar();
+};
+
+template <typename T, typename S>
+struct A : T {
+    auto foo() {
+        static_assert(requires { T::template foo<S>(); });
+        static_assert(requires { T::bar(); });
+    }
+};
+
+int main() {
+    A<B, double> a;
+    a.foo();
+}