From b19d37acc8d2e06fdbe907e3b8250a4ffdc46b04 Mon Sep 17 00:00:00 2001
From: Walter Bright <walter@walterbright.com>
Date: Fri, 26 Oct 2018 00:30:25 -0700
Subject: [PATCH] fix Issue 18457 - betterC - struct destructor is always
 called at function return

---
 src/dmd/func.d          | 11 ++++++++++-
 test/runnable/betterc.d | 29 +++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/src/dmd/func.d b/src/dmd/func.d
index 0e97e582aaf8..7625777a3668 100644
--- a/src/dmd/func.d
+++ b/src/dmd/func.d
@@ -98,8 +98,17 @@ public:
     {
         DtorExpStatement des;
         if (fd.nrvo_can && s.finalbody && (des = s.finalbody.isDtorExpStatement()) !is null &&
-            fd.nrvo_var == des.var && global.params.useExceptions && ClassDeclaration.throwable)
+            fd.nrvo_var == des.var)
         {
+            if (!(global.params.useExceptions && ClassDeclaration.throwable))
+            {
+                /* Don't need to call destructor at all, since it is nrvo
+                 */
+                replaceCurrent(s._body);
+                s._body.accept(this);
+                return;
+            }
+
             /* Normally local variable dtors are called regardless exceptions.
              * But for nrvo_var, its dtor should be called only when exception is thrown.
              *
diff --git a/test/runnable/betterc.d b/test/runnable/betterc.d
index d4655a24d32d..b4b5a725b711 100644
--- a/test/runnable/betterc.d
+++ b/test/runnable/betterc.d
@@ -26,6 +26,7 @@ extern (C) void main()
     test(1);
     test18472();
     testRuntimeLowerings();
+    test18457();
 }
 
 /*******************************************/
@@ -156,3 +157,31 @@ void testRuntimeLowerings()
             break;
     }
 }
+
+/**********************************************/
+// https://issues.dlang.org/show_bug.cgi?id=18457
+
+__gshared int dtor;
+
+struct S18457
+{
+    int a = 3;
+    ~this() { a = 0; ++dtor; }
+}
+
+S18457 myFunction()
+{
+    S18457 s = S18457();
+    return s;
+}
+
+void test18457()
+{
+    {
+        S18457 s = myFunction();
+        assert(s.a == 3);
+        assert(dtor == 0);
+    }
+    assert(dtor == 1);
+}
+