Applied iwyu --comment to the code base (#588)

include/gsl/gsl

@@ -20,8 +20,8 @@
 #include <gsl/gsl_assert>  // Ensures/Expects
 #include <gsl/gsl_util>    // finally()/narrow()/narrow_cast()...
 #include <gsl/multi_span>  // multi_span, strided_span...
+#include <gsl/pointers>    // owner, not_null
 #include <gsl/span>        // span
 #include <gsl/string_span> // zstring, string_span, zstring_builder...
-#include <gsl/pointers>    // owner, not_null
 
 #endif // GSL_GSL_H

include/gsl/gsl_algorithm

@@ -17,9 +17,12 @@
 #ifndef GSL_ALGORITHM_H
 #define GSL_ALGORITHM_H
 
-#include <gsl/span>
+#include <gsl/gsl_assert> // for Expects
+#include <gsl/span>       // for dynamic_extent, span
 
-#include <algorithm>
+#include <algorithm>   // for copy_n
+#include <cstddef>     // for ptrdiff_t
+#include <type_traits> // for is_assignable
 
 #ifdef _MSC_VER
 #pragma warning(push)

include/gsl/gsl_assert

@@ -18,7 +18,7 @@
 #define GSL_CONTRACTS_H
 
 #include <exception>
-#include <stdexcept>
+#include <stdexcept> // for logic_error
 
 //
 // There are three configuration options for this GSL implementation's behavior

include/gsl/gsl_util

@@ -17,12 +17,14 @@
 #ifndef GSL_UTIL_H
 #define GSL_UTIL_H
 
-#include <gsl/gsl_assert> // Ensures/Expects
+#include <gsl/gsl_assert> // for Expects
 
 #include <array>
-#include <exception>
-#include <type_traits>
-#include <utility>
+#include <cstddef>          // for ptrdiff_t, size_t
+#include <exception>        // for exception
+#include <initializer_list> // for initializer_list
+#include <type_traits>      // for is_signed, integral_constant
+#include <utility>          // for forward
 
 #if defined(_MSC_VER)
 

include/gsl/multi_span

@@ -17,22 +17,24 @@
 #ifndef GSL_MULTI_SPAN_H
 #define GSL_MULTI_SPAN_H
 
-#include <gsl/gsl_assert>
-#include <gsl/gsl_byte>
-#include <gsl/gsl_util>
+#include <gsl/gsl_assert> // for Expects
+#include <gsl/gsl_byte>   // for byte
+#include <gsl/gsl_util>   // for narrow_cast
 
-#include <algorithm>
-#include <array>
+#include <algorithm> // for transform, lexicographical_compare
+#include <array>     // for array
 #include <cassert>
-#include <cstddef>
-#include <cstdint>
-#include <functional>
-#include <iterator>
-#include <limits>
+#include <cstddef>          // for ptrdiff_t, size_t, nullptr_t
+#include <cstdint>          // for PTRDIFF_MAX
+#include <functional>       // for divides, multiplies, minus, negate, plus
+#include <initializer_list> // for initializer_list
+#include <iterator>         // for iterator, random_access_iterator_tag
+#include <limits>           // for numeric_limits
 #include <new>
 #include <numeric>
 #include <stdexcept>
-#include <type_traits>
+#include <string>      // for basic_string
+#include <type_traits> // for enable_if_t, remove_cv_t, is_same, is_co...
 #include <utility>
 
 #ifdef _MSC_VER
@@ -1070,7 +1072,6 @@ inline constexpr dim_t<N> dim(std::ptrdiff_t n) GSL_NOEXCEPT
 template <typename ValueType, std::ptrdiff_t FirstDimension = dynamic_range,
           std::ptrdiff_t... RestDimensions>
 class multi_span;
-
 template <typename ValueType, std::size_t Rank>
 class strided_span;
 

include/gsl/pointers

@@ -17,11 +17,13 @@
 #ifndef GSL_POINTERS_H
 #define GSL_POINTERS_H
 
-#include <gsl/gsl_assert>
+#include <gsl/gsl_assert>  // for Ensures, Expects
 
-#include <iosfwd>
-#include <memory>
-#include <type_traits>
+#include <algorithm>    // for forward
+#include <iosfwd>       // for ptrdiff_t, nullptr_t, ostream, size_t
+#include <memory>       // for shared_ptr, unique_ptr
+#include <system_error> // for hash
+#include <type_traits>  // for enable_if_t, is_convertible, is_assignable
 
 #if defined(_MSC_VER) && _MSC_VER < 1910
 #pragma push_macro("constexpr")

include/gsl/span

@@ -17,16 +17,18 @@
 #ifndef GSL_SPAN_H
 #define GSL_SPAN_H
 
-#include <gsl/gsl_assert>
-#include <gsl/gsl_byte>
-#include <gsl/gsl_util>
+#include <gsl/gsl_assert> // for Expects
+#include <gsl/gsl_byte>   // for byte
+#include <gsl/gsl_util>   // for narrow_cast, narrow
 
-#include <array>
-#include <iterator>
+#include <algorithm> // for lexicographical_compare
+#include <array>     // for array
+#include <cstddef>   // for ptrdiff_t, size_t, nullptr_t
+#include <iterator>  // for reverse_iterator, distance, random_access_...
 #include <limits>
-#include <memory>
+#include <memory> // for unique_ptr, shared_ptr
 #include <stdexcept>
-#include <type_traits>
+#include <type_traits> // for enable_if_t, declval, is_convertible, inte...
 #include <utility>
 
 #ifdef _MSC_VER

include/gsl/string_span

@@ -17,13 +17,17 @@
 #ifndef GSL_STRING_SPAN_H
 #define GSL_STRING_SPAN_H
 
-#include <gsl/gsl_assert>
-#include <gsl/gsl_util>
-#include <gsl/span>
+#include <gsl/gsl_assert> // for Ensures, Expects
+#include <gsl/gsl_util>   // for narrow_cast
+#include <gsl/span>       // for operator!=, operator==, dynamic_extent
 
-#include <cstdint>
+#include <algorithm> // for equal, lexicographical_compare
+#include <array>     // for array
+#include <cstddef>   // for ptrdiff_t, size_t, nullptr_t
+#include <cstdint>   // for PTRDIFF_MAX
 #include <cstring>
-#include <string>
+#include <string>      // for basic_string, allocator, char_traits
+#include <type_traits> // for declval, is_convertible, enable_if_t, add_...
 
 #ifdef _MSC_VER
 #pragma warning(push)