--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/Woverride-init-1.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,28 @@
+/* Test for warnings for overriding designated initializers:
+   -Woverride-init.  Bug 24010.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do compile } */
+/* { dg-options "-Woverride-init" } */
+
+struct s { int a; int b; int c; };
+union u { char a; long long b; };
+
+struct s s0 = {
+  .a = 1,
+  .b = 2,
+  .a = 3, /* { dg-warning "initialized field overwritten" } */
+  4, /* { dg-warning "initialized field overwritten" } */
+  5
+};
+
+union u u0 = {
+  .a = 1,
+  .b = 2, /* { dg-warning "initialized field overwritten" } */
+  .a = 3 }; /* { dg-warning "initialized field overwritten" } */
+
+int a[5] = {
+  [0] = 1,
+  [1] = 2,
+  [0] = 3, /* { dg-warning "initialized field overwritten" } */
+  [2] = 4
+};