oleaut32: Update error codes for VarMod.

dlls/oleaut32/tests/vartest.c

@@ -2456,7 +2456,7 @@ static void test_VarMod(void)
 	hexpected = DISP_E_TYPEMISMATCH;
       } else if((l == VT_NULL) && (r == VT_DECIMAL))
       {
-	hexpected = DISP_E_OVERFLOW;
+	hexpected = E_INVALIDARG;
       } else if((l == VT_UNKNOWN) || ((r == VT_UNKNOWN) && lFound && lValid))
       {
 	hexpected = DISP_E_TYPEMISMATCH;
@@ -2465,7 +2465,7 @@ static void test_VarMod(void)
 	hexpected = S_OK;
       } else if((l == VT_DECIMAL) || ((r == VT_DECIMAL) && lFound && lValid))
       {
-	hexpected = DISP_E_OVERFLOW;
+	hexpected = E_INVALIDARG;
       } else if(l == VT_RECORD)
       {
 	hexpected = DISP_E_TYPEMISMATCH;

dlls/oleaut32/variant.c

@@ -4600,7 +4600,7 @@ HRESULT WINAPI VarMod(LPVARIANT left, LPVARIANT right, LPVARIANT result)
       return DISP_E_TYPEMISMATCH;
     case VT_DECIMAL:
       V_VT(result) = VT_EMPTY;
-      return DISP_E_OVERFLOW;
+      return E_INVALIDARG;
     case VT_ERROR:
       return DISP_E_TYPEMISMATCH;
     case VT_RECORD:
@@ -4685,7 +4685,7 @@ HRESULT WINAPI VarMod(LPVARIANT left, LPVARIANT right, LPVARIANT result)
       } else
       {
 	V_VT(result) = VT_EMPTY;
-        return DISP_E_OVERFLOW;
+        return E_INVALIDARG;
       }
     case VT_ERROR:
       return DISP_E_TYPEMISMATCH;