It is highly suspicious when a value is saved for a key or index and then unconditionally overwritten. Such replacements are likely in error.
fruits[1] = "banana"; fruits[1] = "apple"; // Noncompliant - value on index 1 is overwritten myMap.set("key", 1); myMap.set("key", 2); // Noncompliant - value for key "key" is replaced mySet.add(1); mySet.add(1); // Noncompliant - element is already in the set