diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 76835bc..dd76e15 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -853,6 +853,7 @@
       default: assert(0 && "Unknown storage class!");
       case DeclSpec::SCS_auto:        
       case DeclSpec::SCS_register:
+      case DeclSpec::SCS_mutable:
         Diag(D.getIdentifierLoc(), diag::err_typecheck_sclass_func,
              R.getAsString());
         InvalidDecl = true;
@@ -1103,7 +1104,12 @@
     case DeclSpec::SCS_auto:           SC = VarDecl::Auto; break;
     case DeclSpec::SCS_register:       SC = VarDecl::Register; break;
     case DeclSpec::SCS_private_extern: SC = VarDecl::PrivateExtern; break;
-    }    
+    case DeclSpec::SCS_mutable:
+      // mutable can only appear on non-static class members, so it's always
+      // an error here
+      Diag(D.getIdentifierLoc(), diag::err_mutable_nonmember);
+      InvalidDecl = true;
+    }
     if (DC->isCXXRecord()) {
       assert(SC == VarDecl::Static && "Invalid storage class for member!");
       // This is a static data member for a C++ class.
@@ -1121,11 +1127,11 @@
           InvalidDecl = true;
         }
       }
-        NewVD = VarDecl::Create(Context, DC, D.getIdentifierLoc(), 
-                                II, R, SC, LastDeclarator,
-                                // FIXME: Move to DeclGroup...
-                                D.getDeclSpec().getSourceRange().getBegin());
-        NewVD->setThreadSpecified(ThreadSpecified);
+      NewVD = VarDecl::Create(Context, DC, D.getIdentifierLoc(), 
+                              II, R, SC, LastDeclarator,
+                              // FIXME: Move to DeclGroup...
+                              D.getDeclSpec().getSourceRange().getBegin());
+      NewVD->setThreadSpecified(ThreadSpecified);
     }
     // Handle attributes prior to checking for duplicates in MergeVarDecl
     ProcessDeclAttributes(NewVD, D);
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 9bf10ce..f8369b3 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -425,14 +425,44 @@
   Expr *Init = static_cast<Expr*>(InitExpr);
   SourceLocation Loc = D.getIdentifierLoc();
 
+  bool isFunc = D.isFunctionDeclarator();
+
   // C++ 9.2p6: A member shall not be declared to have automatic storage
   // duration (auto, register) or with the extern storage-class-specifier.
+  // C++ 7.1.1p8: The mutable specifier can be applied only to names of class
+  // data members and cannot be applied to names declared const or static,
+  // and cannot be applied to reference members.
   switch (DS.getStorageClassSpec()) {
     case DeclSpec::SCS_unspecified:
     case DeclSpec::SCS_typedef:
     case DeclSpec::SCS_static:
       // FALL THROUGH.
       break;
+    case DeclSpec::SCS_mutable:
+      if (isFunc) {
+        if (DS.getStorageClassSpecLoc().isValid())
+          Diag(DS.getStorageClassSpecLoc(),
+               diag::err_mutable_function);
+        else
+          Diag(DS.getThreadSpecLoc(),
+               diag::err_mutable_function);
+        D.getMutableDeclSpec().ClearStorageClassSpecs();
+      } else {
+        QualType T = GetTypeForDeclarator(D, S);
+        diag::kind err = static_cast<diag::kind>(0);
+        if (T->isReferenceType())
+          err = diag::err_mutable_reference;
+        else if (T.isConstQualified())
+          err = diag::err_mutable_const;
+        if (err != 0) {
+          if (DS.getStorageClassSpecLoc().isValid())
+            Diag(DS.getStorageClassSpecLoc(), err);
+          else
+            Diag(DS.getThreadSpecLoc(), err);
+          D.getMutableDeclSpec().ClearStorageClassSpecs();
+        }
+      }
+      break;
     default:
       if (DS.getStorageClassSpecLoc().isValid())
         Diag(DS.getStorageClassSpecLoc(),
@@ -442,7 +472,6 @@
       D.getMutableDeclSpec().ClearStorageClassSpecs();
   }
 
-  bool isFunc = D.isFunctionDeclarator();
   if (!isFunc &&
       D.getDeclSpec().getTypeSpecType() == DeclSpec::TST_typedef &&
       D.getNumTypeObjects() == 0) {
@@ -455,7 +484,8 @@
     isFunc = Context.getTypeDeclType(cast<TypeDecl>(TD))->isFunctionType();
   }
 
-  bool isInstField = (DS.getStorageClassSpec() == DeclSpec::SCS_unspecified &&
+  bool isInstField = ((DS.getStorageClassSpec() == DeclSpec::SCS_unspecified ||
+                       DS.getStorageClassSpec() == DeclSpec::SCS_mutable) &&
                       !isFunc);
 
   Decl *Member;