Destroy elements in reverse order of construction.

Prevents possibility of last element referencing now invalid first element.

interpreter/cling/lib/Interpreter/Value.cpp

@@ -86,9 +86,11 @@ namespace {
       assert (m_RefCnt > 0 && "Reference count is already zero.");
       if (--m_RefCnt == 0) {
         if (m_DtorFunc) {
-          char* payload = getPayload();
-          for (size_t el = 0; el < m_NElements; ++el)
-            (*m_DtorFunc)(payload + el * m_AllocSize / m_NElements);
+          assert(m_NElements && "No elements!");
+          char* Payload = getPayload();
+          const auto Skip = m_AllocSize / m_NElements;
+          while (m_NElements-- != 0)
+            (*m_DtorFunc)(Payload + m_NElements * Skip);
         }
         delete [] (char*)this;
       }

interpreter/cling/test/Interfaces/evaluate.C

@@ -208,6 +208,18 @@ gCling->evaluate("arrV", V);
 
 V // CHECK-NEXT: (cling::Value &) boxes [(Tracer [3]) { @{{.*}}, @{{.*}}, @{{.*}} }]
 
+// Explicitly destory the copies
+V = cling::Value()
+//CHECK-NEXT: MADE+{10}:dtor
+//CHECK-NEXT: MADE+{9}:dtor
+//CHECK-NEXT: MADE+{8}:dtor
+//CHECK-NEXT: (cling::Value &) <<<invalid>>> @0x{{.*}}
+
+gCling->evaluate("arrV", V);
+//CHECK-NEXT: MADE+{11}:copy
+//CHECK-NEXT: MADE+{12}:copy
+//CHECK-NEXT: MADE+{13}:copy
+
 // Destruct the variables with static storage:
 // Destruct arrV:
 //CHECK-NEXT: MADE{7}:dtor
@@ -217,7 +229,7 @@ V // CHECK-NEXT: (cling::Value &) boxes [(Tracer [3]) { @{{.*}}, @{{.*}}, @{{.*}
 // CHECK-NEXT: VAR{3}:dtor
 // CHECK-NEXT: REF{1}:dtor
 
-//CHECK-NEXT: MADE+{8}:dtor
-//CHECK-NEXT: MADE+{9}:dtor
-//CHECK-NEXT: MADE+{10}:dtor
-
+// V going out of scope
+//CHECK-NEXT: MADE+{13}:dtor
+//CHECK-NEXT: MADE+{12}:dtor
+//CHECK-NEXT: MADE+{11}:dtor