--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/pr85523.C	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,91 @@
+/* { dg-options "-fdiagnostics-show-caret" } */
+
+/* Verify that we emit a "return *this;" fix-it hint for
+   a missing return in an assignment operator.  */
+
+struct s1 {
+  s1& operator=(const s1&) { } // { dg-warning "no return statement in function returning non-void" }
+  /* { dg-begin-multiline-output "" }
+   s1& operator=(const s1&) { }
+                              ^
+                              return *this;
+     { dg-end-multiline-output "" } */
+};
+
+/* Likewise for +=.  */
+
+struct s2 {
+  s2& operator+=(const s2&) {} // { dg-warning "no return statement in function returning non-void" }
+  /* { dg-begin-multiline-output "" }
+   s2& operator+=(const s2&) {}
+                              ^
+                              return *this;
+     { dg-end-multiline-output "" } */
+};
+
+/* No warning for "void" return.  */
+
+struct s3 {
+  void operator=(const s3&) { }
+};
+
+/* We shouldn't issue the fix-it hint if the return type isn't right.  */
+
+struct s4 {
+  int operator=(int) { } // { dg-warning "no return statement in function returning non-void" }
+  /* { dg-begin-multiline-output "" }
+   int operator=(int) { }
+                        ^
+     { dg-end-multiline-output "" } */
+};
+
+/* Example of a multi-line fix-it hint.  */
+
+struct s5 {
+  int i;
+  s5& operator=(const s5& z) {
+    i = z.i;
+  } // { dg-warning "no return statement in function returning non-void" }
+  /* { dg-begin-multiline-output "" }
+     i = z.i;
++    return *this;
+   }
+   ^
+     { dg-end-multiline-output "" } */
+};
+
+/* Example of a multi-line fix-it hint with other statements.  */
+
+extern void log (const char *);
+struct s6 {
+  int i;
+  s6& operator=(const s6& z) {
+    log ("operator=\n");
+    i = z.i;
+  } // { dg-warning "no return statement in function returning non-void" }
+  /* { dg-begin-multiline-output "" }
+     i = z.i;
++    return *this;
+   }
+   ^
+     { dg-end-multiline-output "" } */
+};
+
+/* Another example of a multi-line fix-it hint with other statements.  */
+
+struct s7 {
+  int i;
+  s7& operator=(const s6& z) {
+    if (z.i)
+      log ("operator=\n");
+    else
+      log ("operator=\n");
+    i = z.i;
+  } // { dg-warning "no return statement in function returning non-void" }
+  /* { dg-begin-multiline-output "" }
+     i = z.i;
++    return *this;
+   }
+   ^
+     { dg-end-multiline-output "" } */
+};