diff --git a/register/ShadowValue.h b/register/ShadowValue.h
index 55c71cd..91e9727 100644
--- a/register/ShadowValue.h
+++ b/register/ShadowValue.h
@@ -43,8 +43,6 @@ namespace cppreg {
     };
     template <typename Register>
     typename Register::type Shadow<Register, true>::value = Register::reset;
-    template <typename Register>
-    const bool Shadow<Register, true>::use_shadow;
 
 }
 
diff --git a/single/cppreg-all.h b/single/cppreg-all.h
index b05ebcc..4cf9b9b 100644
--- a/single/cppreg-all.h
+++ b/single/cppreg-all.h
@@ -134,8 +134,6 @@ namespace cppreg {
     };
     template <typename Register>
     typename Register::type Shadow<Register, true>::value = Register::reset;
-    template <typename Register>
-    const bool Shadow<Register, true>::use_shadow;
 }
 #endif