diff --git a/gcc/c-family/c-attribs.cc b/gcc/c-family/c-attribs.cc
index 10d9a51418e..d437c55285e 100644
--- a/gcc/c-family/c-attribs.cc
+++ b/gcc/c-family/c-attribs.cc
@@ -1229,13 +1229,14 @@ handle_hardbool_attribute (tree *node, tree name, tree args,
 
   gcc_checking_assert (!TYPE_CACHED_VALUES_P (*node));
   TYPE_VALUES (*node) = values;
-  TYPE_NAME (*node) = unqual;
 
   if (TYPE_QUALS (orig) != TYPE_QUALS (*node))
-    {
-      *node = build_qualified_type (*node, TYPE_QUALS (orig));
-      TYPE_NAME (*node) = orig;
-    }
+    *node = build_qualified_type (*node, TYPE_QUALS (orig));
+
+  if (TREE_CODE (orig) == TYPE_DECL)
+    TYPE_NAME (*node) = TYPE_NAME (orig);
+  else
+    TYPE_NAME (*node) = NULL_TREE;
 
   return NULL_TREE;
 }
diff --git a/gcc/testsuite/gcc.dg/pr123856.c b/gcc/testsuite/gcc.dg/pr123856.c
new file mode 100644
index 00000000000..2967243220a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr123856.c
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-Wenum-conversion" } */
+
+typedef __attribute__((__hardbool__)) int A, B;
+
+B b;
+void bar(A) { }
+void foo() { bar(b); }		/* { dg-warning "implicit conversion" } */
+
+void bar2(__attribute__((__hardbool__)) int)  { }
+void foo2() { bar2(b); }	/* { dg-warning "implicit conversion" } */
+
+__attribute__((__hardbool__)) int c;
+void bar3(__attribute__((__hardbool__)) int)  { }
+void foo3() { bar2(c); }	/* { dg-warning "implicit conversion" } */
+
+void bar4(int)  { }
+void foo4() { bar2(c); }	/* { dg-warning "implicit conversion" } */
+