[mc] Fix ReadOptions

diff --git a/src/mc/AddressSpace.hpp b/src/mc/AddressSpace.hpp
index 159642f..7c75d44 100644 (file)
--- a/src/mc/AddressSpace.hpp
+++ b/src/mc/AddressSpace.hpp
@@ -145,7 +145,7 @@ public:
   constexpr ReadOptions() : value_(0) {}
 
   constexpr operator bool() const { return value_ != 0; }
-  constexpr operator!() const { return value_ == 0; }
+  constexpr bool operator!() const { return value_ == 0; }
 
   constexpr ReadOptions operator|(ReadOptions const& that) const
   {