Enable more warnings on g++ and fix them

cmake/ACGCompiler.cmake

@@ -46,12 +46,7 @@ if (UNIX)
   # Warnings
   ################################################################################
   
-  IF( NOT CMAKE_SYSTEM MATCHES "SunOS*")
-    list(APPEND ADDITIONAL_CXX_FLAGS          "-W" "-Wall" "-Wno-unused" )
-    list(APPEND ADDITIONAL_C_FLAGS            "-W" "-Wall" "-Wno-unused" )
-  ENDIF()
-
-  if ("${CMAKE_CXX_COMPILER}" MATCHES ".*clang.*")
+  if ("${CMAKE_CXX_COMPILER_ID}" MATCHES ".*Clang.*")
       list(APPEND ADDITIONAL_CXX_FLAGS "-Weverything")
       list(APPEND ADDITIONAL_CXX_FLAGS "-Wno-c++98-compat")
       list(APPEND ADDITIONAL_CXX_FLAGS "-Wno-padded")
@@ -63,6 +58,17 @@ if (UNIX)
       list(APPEND ADDITIONAL_CXX_FLAGS "-Wno-deprecated")
       list(APPEND ADDITIONAL_CXX_FLAGS "-Wno-weak-vtables")
   endif()
+  if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "GNU")
+      list(APPEND ADDITIONAL_CXX_FLAGS "-Wall")
+      list(APPEND ADDITIONAL_CXX_FLAGS "-Wextra")
+      list(APPEND ADDITIONAL_CXX_FLAGS "-Wpedantic")
+      list(APPEND ADDITIONAL_CXX_FLAGS "-Wshadow")
+      list(APPEND ADDITIONAL_CXX_FLAGS "-Wpointer-arith")
+      list(APPEND ADDITIONAL_CXX_FLAGS "-Wcast-qual")
+      list(APPEND ADDITIONAL_CXX_FLAGS "-Wconversion")
+      list(APPEND ADDITIONAL_CXX_FLAGS "-Wtype-limits")
+      list(APPEND ADDITIONAL_CXX_FLAGS "-Wsign-compare")
+  endif()
   
   ################################################################################
   # STL Vector checks

src/OpenVolumeMesh/Core/OpenVolumeMeshProperty.hh

@@ -238,7 +238,7 @@ inline void OpenVolumeMeshPropertyT<bool>::swap(size_t _i0, size_t _i1)
 
     auto tmp = data_[_i0];
     data_[_i0] = data_[_i1];
-    data_[_i1] = tmp;;
+    data_[_i1] = tmp;
 }
 
 template<>

src/OpenVolumeMesh/Core/TopologyKernel.hh

@@ -55,6 +55,7 @@ public:
     TopologyKernel& operator=(const TopologyKernel&) = default;
 
     void assign(const TopologyKernel *other) {
+        assert(other != nullptr);
         *this = *other;
     }
 

src/OpenVolumeMesh/Mesh/HexahedralMeshTopologyKernel.hh

@@ -88,7 +88,7 @@ public:
     static const unsigned char INVALID = 6;
 
     static inline unsigned char opposite_orientation(const unsigned char _d) {
-        return (_d % 2 == 0 ? _d + 1 : _d - 1);
+        return static_cast<unsigned char>(_d % 2 == 0 ? _d + 1 : _d - 1);
     }
 
     // Constructor