diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index cb1929bc5d5..94fbee85225 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -11919,7 +11919,11 @@ trees_out::mark_class_def (tree defn)
 	mark_class_member (member);
 	if (TREE_CODE (member) == FIELD_DECL)
 	  if (tree repr = DECL_BIT_FIELD_REPRESENTATIVE (member))
-	    mark_declaration (repr, false);
+	    /* If we're marking a class template definition, then
+	       this'll contain the width (as set by grokbitfield)
+	       instead of a decl.  */
+	    if (DECL_P (repr))
+	      mark_declaration (repr, false);
       }
 
   /* Mark the binfo hierarchy.  */
diff --git a/gcc/testsuite/g++.dg/modules/bfield-3.H b/gcc/testsuite/g++.dg/modules/bfield-3.H
new file mode 100644
index 00000000000..4fd4db7116a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/bfield-3.H
@@ -0,0 +1,8 @@
+// { dg-additional-options -fmodule-header }
+// { dg-module-cmi {} }
+
+template<int N>
+struct A {
+  int x : 1;
+  int y : N;
+};