diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index eb21dff..a5ce9a0 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -12348,7 +12348,8 @@
   if (!InvalidDecl && Mutable) {
     unsigned DiagID = 0;
     if (T->isReferenceType())
-      DiagID = diag::err_mutable_reference;
+      DiagID = getLangOpts().MSVCCompat ? diag::ext_mutable_reference
+                                        : diag::err_mutable_reference;
     else if (T.isConstQualified())
       DiagID = diag::err_mutable_const;
 
@@ -12357,8 +12358,10 @@
       if (D && D->getDeclSpec().getStorageClassSpecLoc().isValid())
         ErrLoc = D->getDeclSpec().getStorageClassSpecLoc();
       Diag(ErrLoc, DiagID);
-      Mutable = false;
-      InvalidDecl = true;
+      if (DiagID != diag::ext_mutable_reference) {
+        Mutable = false;
+        InvalidDecl = true;
+      }
     }
   }