From 31a8f97423715fa5b4d0977a76e98a8eb83707d0 Mon Sep 17 00:00:00 2001
From: k-hara <k.hara.pg@gmail.com>
Date: Sat, 7 Jan 2012 03:22:30 +0900
Subject: [PATCH] Issue 7230 - Crash during printing anonymous union with
 writeln family functions.

---
 std/format.d | 44 +++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 41 insertions(+), 3 deletions(-)

diff --git a/std/format.d b/std/format.d
index 9f36f6333fd..f48e5e8537b 100644
--- a/std/format.d
+++ b/std/format.d
@@ -1885,9 +1885,24 @@ if ((is(T == struct) || is(T == union)) && !isInputRange!T)
         put(w, left);
         foreach (i, e; val.tupleof)
         {
-            static if (i > 0)
-                put(w, separator);
-            formatElement(w, e, f);
+            static if (0 < i && val.tupleof[i-1].offsetof == val.tupleof[i].offsetof)
+            {
+                static if (i == val.tupleof.length - 1 || val.tupleof[i].offsetof != val.tupleof[i+1].offsetof)
+                    put(w, separator~val.tupleof[i].stringof[4..$]~"}");
+                else
+                    put(w, separator~val.tupleof[i].stringof[4..$]);
+            }
+            else
+            {
+                static if (i+1 < val.tupleof.length && val.tupleof[i].offsetof == val.tupleof[i+1].offsetof)
+                    put(w, (i > 0 ? separator : "")~"#{overlap "~val.tupleof[i].stringof[4..$]);
+                else
+                {
+                    static if (i > 0)
+                        put(w, separator);
+                    formatElement(w, e, f);
+                }
+            }
         }
         put(w, right);
     }
@@ -1954,6 +1969,29 @@ unittest
     assert(a.data == "hello");
 }
 
+unittest
+{
+    // 7230
+    static struct Bug7230
+    {
+        string s = "hello";
+        union {
+            string a;
+            int b;
+            double c;
+        }
+        long x = 10;
+    }
+
+    Bug7230 bug;
+    bug.b = 123;
+
+    FormatSpec!char f;
+    auto w = appender!(char[])();
+    formatValue(w, bug, f);
+    assert(w.data == `Bug7230("hello", #{overlap a, b, c}, 10)`);
+}
+
 /**
    Static-size arrays are formatted just like arrays.
  */