[libc++] Make ThrowingIterator constexpr

[philnik]

Summary

Make ThrowingIterator constexpr

[• Quuxplusone]

libcxx/test/support/test_iterators.h

538

Nit: Here, and I'm guessing on the ctors, I'd prefer to see TEST_CONSTEXPR instead of TEST_CONSTEXPR_CXX14: i.e., pick the most aggressive constexprness possible. (Applies to any single-statement const-qualified member function.)

[philnik]

Replaced some TEST_CONSTEXPR_CXX14 with TEST_CONSTEXPR

libcxx/test/support/test_iterators.h

struct ThrowingIterator {
     typedef std::bidirectional_iterator_tag iterator_category;
     typedef ptrdiff_t                       difference_type;
     typedef const T                         value_type;
     typedef const T *                       pointer;
     typedef const T &                       reference;
 
     enum ThrowingAction { TAIncrement, TADecrement, TADereference, TAAssignment, TAComparison };
 
-    ThrowingIterator()
+    TEST_CONSTEXPR_CXX14 ThrowingIterator()
         : begin_(nullptr), end_(nullptr), current_(nullptr), action_(TADereference), index_(0) {}
-    explicit ThrowingIterator(const T *first, const T *last, int index = 0, ThrowingAction action = TADereference)
+    TEST_CONSTEXPR_CXX14 explicit ThrowingIterator(const T* first, const T* last, int index = 0,
+                                                   ThrowingAction action = TADereference)
         : begin_(first), end_(last), current_(first), action_(action), index_(index) {}
-    ThrowingIterator(const ThrowingIterator &rhs)
+    TEST_CONSTEXPR_CXX14 ThrowingIterator(const ThrowingIterator &rhs)
         : begin_(rhs.begin_), end_(rhs.end_), current_(rhs.current_), action_(rhs.action_), index_(rhs.index_) {}
 
-    ThrowingIterator& operator=(const ThrowingIterator& rhs) {
+    TEST_CONSTEXPR_CXX14 ThrowingIterator& operator=(const ThrowingIterator& rhs) {
         if (action_ == TAAssignment && --index_ < 0) {
 #ifndef TEST_HAS_NO_EXCEPTIONS
             throw std::runtime_error("throw from iterator assignment");
 #else
             assert(false);
 #endif
         }
         begin_ = rhs.begin_;
         end_ = rhs.end_;
         current_ = rhs.current_;
         action_ = rhs.action_;
         index_ = rhs.index_;
         return *this;
     }
 
-    reference operator*() const {
+    TEST_CONSTEXPR_CXX14 reference operator*() const {
         if (action_ == TADereference && --index_ < 0) {
 #ifndef TEST_HAS_NO_EXCEPTIONS
             throw std::runtime_error("throw from iterator dereference");
 #else
             assert(false);
 #endif
         }
         return *current_;
     }
 
-    ThrowingIterator& operator++() {
+    TEST_CONSTEXPR_CXX14 ThrowingIterator& operator++() {
         if (action_ == TAIncrement && --index_ < 0) {
 #ifndef TEST_HAS_NO_EXCEPTIONS
             throw std::runtime_error("throw from iterator increment");
 #else
             assert(false);
 #endif
         }
         ++current_;
         return *this;
     }
 
-    ThrowingIterator operator++(int) {
+    TEST_CONSTEXPR_CXX14 ThrowingIterator operator++(int) {
         ThrowingIterator temp = *this;
         ++(*this);
         return temp;
     }
 
-    ThrowingIterator& operator--() {
+    TEST_CONSTEXPR_CXX14 ThrowingIterator& operator--() {
         if (action_ == TADecrement && --index_ < 0) {
 #ifndef TEST_HAS_NO_EXCEPTIONS
             throw std::runtime_error("throw from iterator decrement");
 #else
             assert(false);
 #endif
         }
         --current_;
         return *this;
     }
 
-    ThrowingIterator operator--(int) {
+    TEST_CONSTEXPR_CXX14 ThrowingIterator operator--(int) {
         ThrowingIterator temp = *this;
         --(*this);
         return temp;
     }
 
-    friend bool operator==(const ThrowingIterator& a, const ThrowingIterator& b) {
+    TEST_CONSTEXPR_CXX14 friend bool operator==(const ThrowingIterator& a, const ThrowingIterator& b) {
         if (a.action_ == TAComparison && --a.index_ < 0) {
 #ifndef TEST_HAS_NO_EXCEPTIONS
             throw std::runtime_error("throw from iterator comparison");
 #else
             assert(false);
 #endif
         }
         bool atEndL = a.current_ == a.end_;
         bool atEndR = b.current_ == b.end_;
         if (atEndL != atEndR) return false;  // one is at the end (or empty), the other is not.
         if (atEndL) return true;             // both are at the end (or empty)
         return a.current_ == b.current_;
     }
 
-    friend bool operator!=(const ThrowingIterator& a, const ThrowingIterator& b) {
+    TEST_CONSTEXPR_CXX14 friend bool operator!=(const ThrowingIterator& a, const ThrowingIterator& b) {
         return !(a == b);
     }
 
     template <class T2>
     void operator,(T2 const &) = delete;
 
 private:
     const T* begin_;