diff --git a/src/opover.c b/src/opover.c
index a82400a56456..b8bd2e4df0c1 100644
--- a/src/opover.c
+++ b/src/opover.c
@@ -1457,7 +1457,7 @@ static Dsymbol *inferApplyArgTypesX(Expression *ethis, FuncDeclaration *fstart,
   struct ParamOpOver
   {
     Parameters *arguments;
-    int mod;
+    unsigned char mod;
     MATCH match;
     FuncDeclaration *fd_best;
     FuncDeclaration *fd_ambig;