diff --git a/src/lol/base/array.h b/src/lol/base/array.h
index 81f8a43d..998b5150 100644
--- a/src/lol/base/array.h
+++ b/src/lol/base/array.h
@@ -95,26 +95,22 @@ public:
         return *this;
     }
 
-    ArrayBase& operator+=(ARRAY const &that)
+    ArrayBase& operator+=(ArrayBase const &that)
     {
         int todo = that.m_count;
         Reserve(m_count + that.m_count);
         for (int i = 0; i < todo; i++)
-            *this << that[i];
+            new(&m_data[m_count + i]) Element(that[i]);
+        m_count += todo;
         return *this;
     }
 
     ARRAY operator+(ARRAY const &that) const
     {
-        /* FIXME: upon return, this makes a copy of the temporary object;
-         * use either C++11 move semantics, or add a special flag to the
-         * object indicating we're a temporary about to be destroyed */
         ARRAY ret;
         ret.Reserve(m_count + that.m_count);
-        for (int i = 0; i < m_count; i++)
-            ret << (*this)[i];
-        for (int i = 0; i < that.m_count; i++)
-            ret << that[i];
+        ret += *this;
+        ret += that;
         return ret;
     }
 
diff --git a/src/lol/base/string.h b/src/lol/base/string.h
index 2eeebe37..7d660ca5 100644
--- a/src/lol/base/string.h
+++ b/src/lol/base/string.h
@@ -118,9 +118,9 @@ public:
 
     inline String& operator +=(String const &s)
     {
-        /* Ignore the trailing zero we don't want */
-        --m_count;
-        (Super &)*this += (Super const &)s;
+        int old_count = Count();
+        Resize(Count() + s.Count());
+        memcpy(&(*this)[old_count], &s[0], Count() - old_count);
         return *this;
     }
 
diff --git a/test/unit/string.cpp b/test/unit/string.cpp
index 11c32ce9..ea0e6101 100644
--- a/test/unit/string.cpp
+++ b/test/unit/string.cpp
@@ -140,13 +140,13 @@ LOLUNIT_FIXTURE(StringTest)
     {
         String s1 = "Hello World";
 
-        String s2 = "Hello";
-        String s3 = s1.Sub(0, 5);
-        LOLUNIT_ASSERT(s3 == s2);
+        String s2 = s1.Sub(0, 5);
+        String s3 = "Hello";
+        LOLUNIT_ASSERT(s2 == s3);
 
-        String s4 = "World";
-        String s5 = s4.Sub(6, 5);
-        LOLUNIT_ASSERT(s5 == s4);
+        String s4 = s1.Sub(6, 5);
+        String s5 = "World";
+        LOLUNIT_ASSERT(s4 == s5);
     }
 };