diff --git a/ldblib.c b/ldblib.c
index 6ca713ce..63602f95 100644
--- a/ldblib.c
+++ b/ldblib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ldblib.c,v 1.58 2002/06/18 15:17:58 roberto Exp roberto $
+** $Id: ldblib.c,v 1.59 2002/06/18 17:10:43 roberto Exp roberto $
 ** Interface from Lua to its debug API
 ** See Copyright Notice in lua.h
 */
@@ -126,12 +126,17 @@ static void hookf (lua_State *L, void *key) {
 
 static void callf (lua_State *L, lua_Debug *ar) {
   lua_pushstring(L, ar->event);
+  lua_assert(lua_getinfo(L, "lS", ar) && ar->currentline == -1);
   hookf(L, (void *)&KEY_CALLHOOK);
 }
 
 
 static void linef (lua_State *L, lua_Debug *ar) {
   lua_pushnumber(L, ar->currentline);
+  lua_assert((ar->currentline = ar->linedefined = -1,
+                lua_getinfo(L, "lS", ar) &&
+                ar->currentline == lua_tonumber(L, -1) &&
+                ar->linedefined >= 0));
   hookf(L, (void *)&KEY_LINEHOOK);
 }
 
diff --git a/ldo.c b/ldo.c
index e9bd41ae..be9b3d4d 100644
--- a/ldo.c
+++ b/ldo.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ldo.c,v 1.180 2002/06/18 15:19:27 roberto Exp roberto $
+** $Id: ldo.c,v 1.181 2002/06/18 17:10:43 roberto Exp roberto $
 ** Stack and Call structure of Lua
 ** See Copyright Notice in lua.h
 */
@@ -138,6 +138,7 @@ static void luaD_openstack (lua_State *L, StkId pos) {
 static void dohook (lua_State *L, lua_Debug *ar, lua_Hook hook) {
   ptrdiff_t top = savestack(L, L->top);
   ptrdiff_t ci_top = savestack(L, L->ci->top);
+  ar->i_ci = L->ci - L->base_ci;
   luaD_checkstack(L, LUA_MINSTACK);  /* ensure minimum stack size */
   L->ci->top = L->top + LUA_MINSTACK;
   L->allowhooks = 0;  /* cannot call hooks inside a hook */
@@ -155,7 +156,6 @@ void luaD_lineHook (lua_State *L, int line) {
   if (L->allowhooks) {
     lua_Debug ar;
     ar.event = "line";
-    ar.i_ci = L->ci - L->base_ci;
     ar.currentline = line;
     dohook(L, &ar, L->linehook);
   }
@@ -166,7 +166,6 @@ static void luaD_callHook (lua_State *L, lua_Hook callhook, const char *event) {
   if (L->allowhooks) {
     lua_Debug ar;
     ar.event = event;
-    ar.i_ci = L->ci - L->base_ci;
     L->ci->pc = NULL;  /* function is not active */
     L->ci->top = L->ci->base;  /* `top' may not have a valid value yet */ 
     dohook(L, &ar, callhook);
diff --git a/lualib.h b/lualib.h
index 68d88d7e..23c0298b 100644
--- a/lualib.h
+++ b/lualib.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lualib.h,v 1.22 2002/04/09 20:19:06 roberto Exp roberto $
+** $Id: lualib.h,v 1.23 2002/06/05 17:24:04 roberto Exp roberto $
 ** Lua standard libraries
 ** See Copyright Notice in lua.h
 */
@@ -38,4 +38,9 @@ LUALIB_API int lua_mathlibopen (lua_State *L);
 LUALIB_API int lua_dblibopen (lua_State *L);
 
 
+/* to help testing the libraries */
+#ifndef lua_assert
+#define lua_assert(c)		/* empty */
+#endif
+
 #endif