Merge remote-tracking branch 'oiffrig/underlying_type'

Author: Архипов Дмитрий

include/flags/flags.hpp

@@ -140,15 +140,15 @@ template <class E> class flags {
   }
 
   friend constexpr flags operator|(flags f1, flags f2) noexcept {
-    return flags{f1.val_ | f2.val_};
+    return flags{static_cast<impl_type>(f1.val_ | f2.val_)};
   }
 
   friend constexpr flags operator&(flags f1, flags f2) noexcept {
-    return flags{f1.val_ & f2.val_};
+    return flags{static_cast<impl_type>(f1.val_ & f2.val_)};
   }
 
   friend  constexpr flags operator^(flags f1, flags f2) noexcept {
-    return flags{f1.val_ ^ f2.val_};
+    return flags{static_cast<impl_type>(f1.val_ ^ f2.val_)};
   }
 
 

test/Jamroot

@@ -3,6 +3,7 @@ import testing ;
 
 project flags_tests
   : requirements <warnings>all
+                 <warnings-as-errors>on
                  <cxxflags>-std=c++11
                  <include>../include/
   : default-build <variant>release

test/common.hpp

@@ -11,4 +11,10 @@ ALLOW_FLAGS_FOR_ENUM(Enum)
 using Enums = flags::flags<Enum>;
 
 
+enum class SmallEnum : unsigned char {SmallOne = 1, SmallTwo = 2, SmallFour = 4, SmallEight = 8};
+ALLOW_FLAGS_FOR_ENUM(SmallEnum)
+
+using SmallEnums = flags::flags<SmallEnum>;
+
+
 #endif // ENUM_CLASS_TEST_COMMON_HPP

test/should-compile.cpp

@@ -147,11 +147,18 @@ constexpr Enums::iterator cf3 = ec1.find(Enum::One);
 constexpr Enums::size_type cf4 = ec1.count(Enum::One);
 
 
+// non-int underlying type with bitwise operators
+constexpr SmallEnums s1(SmallEnum::SmallOne);
+constexpr auto s2 = s1 | s1;
+constexpr auto s3 = s1 & s1;
+constexpr auto s4 = s1 ^ s1;
+
+
 template <class... Ts> void ignore_variables(Ts&&...) {}
 
 void do_ignore_variables() {
   ignore_variables(
     vc1, vc2, l1, l2, l3, l4, b1, b2, b3, b4, b5, b6, b7, b8, b9, b10, b11,
-    b12, b13, cv1, cf1, cf2, cf3, cf4
+    b12, b13, cv1, cf1, cf2, cf3, cf4, s2, s3, s4
   );
 }