bugprone-missing-end-comparison

Finds instances where the result of a standard algorithm is used in a Boolean context without being compared to the end iterator.

Standard algorithms such as std::find, std::search, and std::lower_bound return an iterator to the element if found, or the end iterator otherwise.

Using the result directly in a Boolean context (like an if statement) is almost always a bug, as it only checks if the iterator itself evaluates to true, which may always be true for many iterator types.

Examples:

void example() {
  int arr[] = {1, 2, 3};
  int* begin = std::begin(arr);
  int* end = std::end(arr);

  if (std::find(begin, end, 2)) {
    // ...
  }

  // Fixed by the check:
  if ((std::find(begin, end, 2) != end)) {
    // ...
  }

  // C++20 ranges:
  int v[] = {1, 2, 3};
  if (std::ranges::find(v, 2)) {
    // ...
  }

  // Fixed by the check:
  if ((std::ranges::find(v, 2) != std::ranges::end(v))) {
    // ...
  }
}

The check also handles range-based algorithms introduced in C++20.

Supported algorithms:

• std::adjacent_find

• std::find

• std::find_end

• std::find_first_of

• std::find_if

• std::find_if_not

• std::is_sorted_until

• std::lower_bound

• std::max_element

• std::min_element

• std::partition_point

• std::search

• std::search_n

• std::upper_bound

• std::ranges::adjacent_find

• std::ranges::find

• std::ranges::find_first_of

• std::ranges::find_if

• std::ranges::find_if_not

• std::ranges::is_sorted_until

• std::ranges::lower_bound

• std::ranges::max_element

• std::ranges::min_element

• std::ranges::upper_bound

Options

ExtraAlgorithms

A semicolon-separated list of extra algorithms to check. The list can contain:

• Iterator-based algorithms. These should follow the standard iterator pattern: func(Iter, Iter, ...).

• Range-based algorithms. These are heuristically detected if they take exactly two arguments and the first argument is a container or range. The fix will insert std::end(Container).

Default is an empty string.