diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 2c5308fbcb319..a146dedb125a3 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -630,6 +630,7 @@ Bug Fixes to C++ Support
 - Fix a bug on template partial specialization with issue on deduction of nontype template parameter
   whose type is `decltype(auto)`. Fixes (#GH68885).
 - Clang now correctly treats the noexcept-specifier of a friend function to be a complete-class context.
+- Fix an assertion failure when parsing an invalid members of an anonymous class. (#GH85447)
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 79fb6c0417e33..19968452f0d56 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -5790,6 +5790,9 @@ Decl *Sema::BuildAnonymousStructOrUnion(Scope *S, DeclSpec &DS,
     Anon = VarDecl::Create(Context, Owner, DS.getBeginLoc(),
                            Record->getLocation(), /*IdentifierInfo=*/nullptr,
                            Context.getTypeDeclType(Record), TInfo, SC);
+    if (Invalid)
+      Anon->setInvalidDecl();
+
     ProcessDeclAttributes(S, Anon, Dc);
 
     // Default-initialize the implicit variable. This initialization will be
diff --git a/clang/test/Sema/incomplete-struct-decl.cpp b/clang/test/Sema/incomplete-struct-decl.cpp
new file mode 100644
index 0000000000000..bc3bd6b2eae2f
--- /dev/null
+++ b/clang/test/Sema/incomplete-struct-decl.cpp
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -x c++ -fsyntax-only -verify=cxx,expected %s
+
+template <class a> using __impl_of = a; // expected-note {{'__impl_of' declared here}} \
+                                           expected-note {{template is declared here}}
+struct {                                // expected-error {{anonymous structs and classes must be class members}} \
+                                           expected-note {{to match this '{'}}
+  __impl_;                              // expected-error {{no template named '__impl_'; did you mean '__impl_of'?}} \
+                                           expected-error {{cannot specify deduction guide for alias template '__impl_of'}} \
+                                           expected-error {{expected ';' after struct}}
+                                        // expected-error {{expected '}'}}