diff --git a/CMakeLists.txt b/CMakeLists.txt
index 58cc7685cf..c33c4a3c30 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -227,7 +227,7 @@ endif ()
 
 # set necessary flags to compile code as is
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${TARGET_M} -std=gnu99 ${COMMON_COMPILE_OPTIONS}")
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${TARGET_M} -std=gnu++11 ${COMMON_COMPILE_OPTIONS}")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${TARGET_M} -std=gnu++11 ${COMMON_COMPILE_OPTIONS} -Wnon-virtual-dtor")
 set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${TARGET_M}")
 set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${CMAKE_SHARED_LINKER_FLAGS} ${PIE_FLAG}")
 
diff --git a/src/core/StringReader.hpp b/src/core/StringReader.hpp
index 1287a5e5ef..aee09b43b9 100644
--- a/src/core/StringReader.hpp
+++ b/src/core/StringReader.hpp
@@ -23,6 +23,8 @@
 
 interface IStringReader
 {
+    virtual ~IStringReader() = default;
+
     virtual bool TryPeek(codepoint_t * outCodepoint)       abstract;
     virtual bool TryRead(codepoint_t * outCodepoint)       abstract;
     virtual void Skip()                                    abstract;