From 1e2c29f2632c378843c5a3c9ad401a7bcacc4de0 Mon Sep 17 00:00:00 2001
From: Kaz Wesley <keziahw@gmail.com>
Date: Wed, 13 Apr 2016 10:09:16 -0700
Subject: [PATCH] prevector: destroy elements only via erase()

Fixes a bug in which pop_back did not call the deleted item's destructor.

Using the most general erase() implementation to implement all the others
prevents similar bugs because the coupling between deallocation and destructor
invocation only needs to be maintained in one place.
Also reduces duplication of complex memmove logic.
---
 src/prevector.h | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/src/prevector.h b/src/prevector.h
index 1da459bcfe..16b2f8dca7 100644
--- a/src/prevector.h
+++ b/src/prevector.h
@@ -298,9 +298,8 @@ public:
     }
 
     void resize(size_type new_size) {
-        while (size() > new_size) {
-            item_ptr(size() - 1)->~T();
-            _size--;
+        if (size() > new_size) {
+            erase(item_ptr(new_size), end());
         }
         if (new_size > capacity()) {
             change_capacity(new_size);
@@ -368,10 +367,7 @@ public:
     }
 
     iterator erase(iterator pos) {
-        (*pos).~T();
-        memmove(&(*pos), &(*pos) + 1, ((char*)&(*end())) - ((char*)(1 + &(*pos))));
-        _size--;
-        return pos;
+        return erase(pos, pos + 1);
     }
 
     iterator erase(iterator first, iterator last) {
@@ -396,7 +392,7 @@ public:
     }
 
     void pop_back() {
-        _size--;
+        erase(end() - 1, end());
     }
 
     T& front() {