diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index 05d97a7..6232070 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -6721,10 +6721,6 @@ struct flexmems_t
        };
   */
   tree after[2];
-
-  /* The type in which an anonymous struct or union containing ARRAY
-     is defined or null if no such anonymous struct or union exists.  */
-  tree anonctx;
 };
 
 /* Find either the first flexible array member or the first zero-length
@@ -6826,14 +6822,9 @@ find_flexarrays (tree t, flexmems_t *fmem, bool base_p,
 	      find_flexarrays (eltype, fmem, false, pun);
 
 	      if (fmem->array != array)
-		{
-		  /* If the member struct contains the first flexible array
-		     member, store the enclosing struct if it is anonymous.  */
-		  if (anon_p)
-		    fmem->anonctx = t;
-		  continue;
-		}
-	      else if (first && !array && !anon_p)
+		continue;
+
+	      if (first && !array && !anon_p)
 		{
 		  /* Restore the FIRST member reset above if no flexible
 		     array member has been found in this member's struct.  */
@@ -6904,6 +6895,22 @@ find_flexarrays (tree t, flexmems_t *fmem, bool base_p,
     }
 }
 
+/* Return the type in which the member T is effectively declared in.
+   This is either the member's enclosing struct for ordinary members,
+   or for anonymous structs and unions, the first non-anonymou struct
+   or union they are declared in.  */
+
+static tree
+anon_context (tree t)
+{
+  if (TREE_CODE (t) == FIELD_DECL)
+    return anon_context (DECL_CONTEXT (t));
+
+  bool anon_p = ANON_AGGR_TYPE_P (t);
+
+  return anon_p ? anon_context (TYPE_CONTEXT (t)) : t;
+}
+
 /* Issue diagnostics for invalid flexible array members or zero-length
    arrays that are not the last elements of the containing class or its
    base classes or that are its sole members.  */
@@ -6913,7 +6920,7 @@ diagnose_flexarrays (tree t, const flexmems_t *fmem)
 {
   /* Members of anonymous structs and unions are considered to be members
      of the containing struct or union.  */
-  if (!fmem->array)
+  if (!fmem->array || (fmem->first && !fmem->after[0] && !fmem->after[1]))
     return;
 
   /* Issue errors first, and when no errors are found, then warnings
@@ -6923,7 +6930,10 @@ diagnose_flexarrays (tree t, const flexmems_t *fmem)
     /* The context of the flexible array member.  Either the struct
        in which it's declared or, for anonymous structs and unions,
        the struct/union of which the array is effectively a member.  */
-    tree fmemctx = fmem->anonctx ? fmem->anonctx : t;
+    tree fmemctx = anon_context (fmem->array);
+    bool anon_p = fmemctx != DECL_CONTEXT (fmem->array);
+    if (!anon_p)
+      fmemctx = t;
 
     const char *msg = 0;
 
@@ -6931,7 +6941,7 @@ diagnose_flexarrays (tree t, const flexmems_t *fmem)
       {
 	if (fmem->after[in_union])
 	  msg = (in_union
-		 ? (fmem->anonctx
+		 ? (anon_p
 		    ? G_("zero-size array member %qD belonging to %q#T")
 		    : G_("zero-size array member %qD"))
 		 : G_("zero-size array member %qD not at end of %q#T"));
@@ -6970,7 +6980,7 @@ diagnose_flexarrays (tree t, const flexmems_t *fmem)
       {
 	if (fmem->after[in_union])
 	  msg = (in_union
-		 ? (fmem->anonctx
+		 ? (anon_p
 		    ? G_("flexible array member %qD belonging to %q#T")
 		    : G_("flexible array member %qD"))
 		 : G_("flexible array member %qD not at end of %q#T"));