diff --git a/src/SysYIRGenerator.cpp b/src/SysYIRGenerator.cpp
index 8847ea2..82e6a30 100644
--- a/src/SysYIRGenerator.cpp
+++ b/src/SysYIRGenerator.cpp
@@ -256,10 +256,6 @@ namespace sysy
     return call;
   }
 
-  any SysYIRGenerator::visitCondExp(SysYParser::ExpContext *ctx)
-  {
-  }
-
   any SysYIRGenerator::visitIfStmt(SysYParser::IfStmtContext *ctx)
   {
     // generate condition expression
diff --git a/src/SysYIRGenerator.h b/src/SysYIRGenerator.h
index f8d70fa..5264c09 100644
--- a/src/SysYIRGenerator.h
+++ b/src/SysYIRGenerator.h
@@ -246,7 +246,7 @@ namespace sysy
       return visitChildren(ctx);
     }
     virtual std::any
-    visitCondExp(SysYParser::ExpContext *ctx) override;
+    visitCondExp(SysYParser::ExpContext *ctx) { return visitChildren(ctx); }
 
   private:
     std::any visitGlobalDecl(SysYParser::DeclContext *ctx);