1 files changed, 8 insertions, 0 deletions
diff --git a/sem_check.c b/sem_check.c
index ae1fa4c..2e9b5ba 100644
--- a/sem_check.c
+++ b/sem_check.c
@@ -53,6 +53,14 @@ ptree *t;
 
 	case ADDOP :
 	case MULOP :
+		if (!(t->r && t->l))
+			yyerror("Missing nodes\n");
+
+		if (t->r->ret_type == t->l->ret_type)
+			return t->r->ret_type;
+		else
+			yyerror("Misssing nodes\n");
+		break;
 	case RELOP :
 		if (!(t->r && t->l))
 			yyerror("Missing nodes\n");