Merge pull request #51 from halfflat/feature/fix-gcc6-optional-warning

Address gcc 6.1 warnings

src/point.hpp

@@ -62,7 +62,7 @@ template <typename T>
 T
 norm(point<T> const& p)
 {
-    return sqrt(p.x*p.x + p.y*p.y + p.z*p.z);
+    return std::sqrt(p.x*p.x + p.y*p.y + p.z*p.z);
 }
 
 template <typename T>

src/util/optional.hpp

@@ -226,6 +226,13 @@ namespace detail {
     template <typename T>
     using enable_unless_optional_t = enable_if_t<!is_optional<T>::value>;
 
+    // avoid nonnull address warnings when using operator| with e.g. char array constants
+    template <typename T>
+    bool decay_bool(const T* x) { return static_cast<bool>(x); }
+
+    template <typename T>
+    bool decay_bool(const T& x) { return static_cast<bool>(x); }
+
 } // namespace detail
 
 template <typename X>
@@ -398,7 +405,7 @@ typename std::enable_if<
     >
 >::type
 operator|(A&& a,B&& b) {
-    return a ? a : b;
+    return detail::decay_bool(a) ? a : b;
 }
 
 template <typename A,typename B>