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+# container-anti-pattern
+
+Finds when temporary containers are being created needlessly.
+These cases are usually easy to fix by using iterators, avoiding memory allocations.
+
+Matches code like:
+
+    {QMap, QHash, QSet}.values().*
+    {QMap, QHash}.keys().*
+    {QVector, QSet}.toList().*
+    QList::toVector().*
+    QSet::intersect(other).isEmpty()
+    for (auto i : {QHash, QMap}.values()) {}
+    foreach (auto i, {QHash, QMap}.values()) {}
+
+#### Example
+
+    set.toList()[0]; // use set.constFirst() instead
+    hash.values().size(); // Use hash.size() instead
+    hash.keys().contains(); // Use hash.contains() instead
+    hash.values().contains(); // Use std::find(hash.cbegin(), hash.cend(), myValue) instead
+    map.values(k).foo ; // Use QMap::equal_range(k) instead
+    for (auto i : hash.values()) {} // Iterate the hash directly instead: for (auto i : hash) {}
+    QSet::intersect(other).isEmpty() // Use QSet::intersects() instead, avoiding memory allocations and iterations, since Qt 5.6