diff --git a/src/memory/SharedPtr.cpp b/src/memory/SharedPtr.cpp
index b4f5ef48bb..2530360a5a 100644
--- a/src/memory/SharedPtr.cpp
+++ b/src/memory/SharedPtr.cpp
@@ -32,11 +32,12 @@ namespace Sass {
   bool SharedObj::taint = false;
 
   SharedObj::SharedObj()
-  : refcounter(0)
+  : detached(false)
     #ifdef DEBUG_SHARED_PTR
     , dbg(false)
     #endif
   {
+    refcounter = 0;
     #ifdef DEBUG_SHARED_PTR
       if (taint) all.push_back(this);
     #endif
@@ -62,7 +63,9 @@ namespace Sass {
           // AST_Node_Ptr ast = dynamic_cast<AST_Node*>(node);
           if (node->dbg) std::cerr << "DELETE NODE " << node << "\n";
         #endif
-        delete(node);
+        if (!node->detached) {
+          delete(node);
+        }
       }
     }
   }
@@ -70,6 +73,7 @@ namespace Sass {
   void SharedPtr::incRefCount() {
     if (node) {
       ++ node->refcounter;
+      node->detached = false;
       #ifdef DEBUG_SHARED_PTR
         if (node->dbg) {
           std::cerr << "+ " << node << " X " << node->refcounter << " (" << this << ") " << "\n";
@@ -107,4 +111,4 @@ namespace Sass {
     incRefCount();
   }
 
-}
+}
\ No newline at end of file
diff --git a/src/memory/SharedPtr.hpp b/src/memory/SharedPtr.hpp
index fbfd003125..7e13bf06c7 100644
--- a/src/memory/SharedPtr.hpp
+++ b/src/memory/SharedPtr.hpp
@@ -49,6 +49,8 @@ namespace Sass {
     #endif
     static bool taint;
     long refcounter;
+    // long refcount;
+    bool detached;
     #ifdef DEBUG_SHARED_PTR
       bool dbg;
     #endif
@@ -80,7 +82,7 @@ namespace Sass {
     virtual const std::string to_string() const = 0;
 
     virtual ~SharedObj();
-    long getRefCount() const {
+    long getRefCount() {
       return refcounter;
     }
   };
@@ -121,10 +123,11 @@ namespace Sass {
     bool isNull () const {
       return node == NULL;
     };
-    SharedObj* detach() {
-      SharedObj* result = node;
-      node = NULL;
-      return result;
+    SharedObj* detach() const {
+      if (node) {
+        node->detached = true;
+      }
+      return node;
     };
     operator bool() const {
       return node != NULL;
@@ -194,7 +197,8 @@ namespace Sass {
     T* ptr () const {
       return static_cast<T*>(this->obj());
     };
-    T* detach() {
+    T* detach() const {
+      if (this->obj() == NULL) return NULL;
       return static_cast<T*>(SharedPtr::detach());
     }
     bool isNull() const {
@@ -210,4 +214,4 @@ namespace Sass {
 
 }
 
-#endif
+#endif
\ No newline at end of file