diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1cfeefc..56da828 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -50,7 +50,7 @@ set(YACC_GENERATED_SOURCE_FILE ${PROJECT_SOURCE_DIR}/src/yacc/parser.tab.c)
 
 add_custom_command(OUTPUT ${YACC_GENERATED_SOURCE_FILE}
         COMMAND yacc
-        ARGS -d -o ${YACC_GENERATED_SOURCE_FILE} ${YACC_SOURCE_FILE}
+        ARGS -Wcounterexamples -d -o ${YACC_GENERATED_SOURCE_FILE} ${YACC_SOURCE_FILE}
         COMMENT "generate C source file for parser"
         VERBATIM)