62 files changed, 1490 insertions, 672 deletions

diff --git a/lapi.c b/lapi.c
index f59430a7..0c88751a 100644
--- a/lapi.c
+++ b/lapi.c
@@ -440,7 +440,7 @@ LUA_API lua_Unsigned lua_rawlen (lua_State *L, int idx) {
     case LUA_VSHRSTR: return cast(lua_Unsigned, tsvalue(o)->shrlen);
     case LUA_VLNGSTR: return cast(lua_Unsigned, tsvalue(o)->u.lnglen);
     case LUA_VUSERDATA: return cast(lua_Unsigned, uvalue(o)->len);
-    case LUA_VTABLE: return luaH_getn(hvalue(o));
+    case LUA_VTABLE: return luaH_getn(L, hvalue(o));
     default: return 0;
   }
 }
@@ -593,12 +593,8 @@ LUA_API const char *lua_pushfstring (lua_State *L, const char *fmt, ...) {
   const char *ret;
   va_list argp;
   lua_lock(L);
-  va_start(argp, fmt);
-  ret = luaO_pushvfstring(L, fmt, argp);
-  va_end(argp);
+  pushvfstring(L, argp, fmt, ret);
   luaC_checkGC(L);
-  if (ret == NULL)  /* error? */
-    luaD_throw(L, LUA_ERRMEM);
   lua_unlock(L);
   return ret;
 }
@@ -683,7 +679,7 @@ static int auxgetstr (lua_State *L, const TValue *t, const char *k) {
 
 /*
 ** The following function assumes that the registry cannot be a weak
-** table, so that en mergency collection while using the global table
+** table; so, an emergency collection while using the global table
 ** cannot collect it.
 */
 static void getGlobalTable (lua_State *L, TValue *gt) {
diff --git a/lauxlib.c b/lauxlib.c
index 7c9ad53b..7f33f0ad 100644
--- a/lauxlib.c
+++ b/lauxlib.c
@@ -94,14 +94,14 @@ static int pushglobalfuncname (lua_State *L, lua_Debug *ar) {
 
 
 static void pushfuncname (lua_State *L, lua_Debug *ar) {
-  if (pushglobalfuncname(L, ar)) {  /* try first a global name */
-    lua_pushfstring(L, "function '%s'", lua_tostring(L, -1));
-    lua_remove(L, -2);  /* remove name */
-  }
-  else if (*ar->namewhat != '\0')  /* is there a name from code? */
+  if (*ar->namewhat != '\0')  /* is there a name from code? */
     lua_pushfstring(L, "%s '%s'", ar->namewhat, ar->name);  /* use it */
   else if (*ar->what == 'm')  /* main? */
       lua_pushliteral(L, "main chunk");
+  else if (pushglobalfuncname(L, ar)) {  /* try a global name */
+    lua_pushfstring(L, "function '%s'", lua_tostring(L, -1));
+    lua_remove(L, -2);  /* remove name */
+  }
   else if (*ar->what != 'C')  /* for Lua functions, use <file:line> */
     lua_pushfstring(L, "function <%s:%d>", ar->short_src, ar->linedefined);
   else  /* nothing left... */
diff --git a/lcode.c b/lcode.c
index 8c04d8ab..7ca895f1 100644
--- a/lcode.c
+++ b/lcode.c
@@ -40,7 +40,10 @@ static int codesJ (FuncState *fs, OpCode o, int sj, int k);
 
 
 /* semantic error */
-l_noret luaK_semerror (LexState *ls, const char *msg) {
+l_noret luaK_semerror (LexState *ls, const char *fmt, ...) {
+  const char *msg;
+  va_list argp;
+  pushvfstring(ls->L, argp, fmt, msg);
   ls->t.token = 0;  /* remove "near <token>" from final message */
   luaX_syntaxerror(ls, msg);
 }
@@ -750,10 +753,11 @@ void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {
 /*
 ** Convert a VKSTR to a VK
 */
-static void str2K (FuncState *fs, expdesc *e) {
+static int str2K (FuncState *fs, expdesc *e) {
   lua_assert(e->k == VKSTR);
   e->u.info = stringK(fs, e->u.strval);
   e->k = VK;
+  return e->u.info;
 }
 
 
@@ -1304,35 +1308,38 @@ void luaK_self (FuncState *fs, expdesc *e, expdesc *key) {
 ** values in registers.
 */
 void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {
+  int keystr = -1;
   if (k->k == VKSTR)
-    str2K(fs, k);
+    keystr = str2K(fs, k);
   lua_assert(!hasjumps(t) &&
              (t->k == VLOCAL || t->k == VNONRELOC || t->k == VUPVAL));
   if (t->k == VUPVAL && !isKstr(fs, k))  /* upvalue indexed by non 'Kstr'? */
     luaK_exp2anyreg(fs, t);  /* put it in a register */
   if (t->k == VUPVAL) {
     lu_byte temp = cast_byte(t->u.info);  /* upvalue index */
-    lua_assert(isKstr(fs, k));
     t->u.ind.t = temp;  /* (can't do a direct assignment; values overlap) */
-    t->u.ind.idx = cast(short, k->u.info);  /* literal short string */
+    lua_assert(isKstr(fs, k));
+    t->u.ind.idx = cast_short(k->u.info);  /* literal short string */
     t->k = VINDEXUP;
   }
   else {
     /* register index of the table */
     t->u.ind.t = cast_byte((t->k == VLOCAL) ? t->u.var.ridx: t->u.info);
     if (isKstr(fs, k)) {
-      t->u.ind.idx = cast(short, k->u.info);  /* literal short string */
+      t->u.ind.idx = cast_short(k->u.info);  /* literal short string */
       t->k = VINDEXSTR;
     }
     else if (isCint(k)) {  /* int. constant in proper range? */
-      t->u.ind.idx = cast(short, k->u.ival);
+      t->u.ind.idx = cast_short(k->u.ival);
       t->k = VINDEXI;
     }
     else {
-      t->u.ind.idx = cast(short, luaK_exp2anyreg(fs, k));  /* register */
+      t->u.ind.idx = cast_short(luaK_exp2anyreg(fs, k));  /* register */
       t->k = VINDEXED;
     }
   }
+  t->u.ind.keystr = keystr;  /* string index in 'k' */
+  t->u.ind.ro = 0;  /* by default, not read-only */
 }
 
 
diff --git a/lcode.h b/lcode.h
index 414ebe39..94fc2417 100644
--- a/lcode.h
+++ b/lcode.h
@@ -97,7 +97,7 @@ LUAI_FUNC void luaK_settablesize (FuncState *fs, int pc,
                                   int ra, int asize, int hsize);
 LUAI_FUNC void luaK_setlist (FuncState *fs, int base, int nelems, int tostore);
 LUAI_FUNC void luaK_finish (FuncState *fs);
-LUAI_FUNC l_noret luaK_semerror (LexState *ls, const char *msg);
+LUAI_FUNC l_noret luaK_semerror (LexState *ls, const char *fmt, ...);
 
 
 #endif
diff --git a/lcorolib.c b/lcorolib.c
index 3d95f873..23dd8441 100644
--- a/lcorolib.c
+++ b/lcorolib.c
@@ -154,8 +154,13 @@ static int luaB_costatus (lua_State *L) {
 }
 
 
+static lua_State *getoptco (lua_State *L) {
+  return (lua_isnone(L, 1) ? L : getco(L));
+}
+
+
 static int luaB_yieldable (lua_State *L) {
-  lua_State *co = lua_isnone(L, 1) ? L : getco(L);
+  lua_State *co = getoptco(L);
   lua_pushboolean(L, lua_isyieldable(co));
   return 1;
 }
@@ -169,7 +174,7 @@ static int luaB_corunning (lua_State *L) {
 
 
 static int luaB_close (lua_State *L) {
-  lua_State *co = getco(L);
+  lua_State *co = getoptco(L);
   int status = auxstatus(L, co);
   switch (status) {
     case COS_DEAD: case COS_YIELD: {
@@ -184,6 +189,13 @@ static int luaB_close (lua_State *L) {
         return 2;
       }
     }
+    case COS_RUN:  /* running coroutine? */
+      lua_geti(L, LUA_REGISTRYINDEX, LUA_RIDX_MAINTHREAD);  /* get main */
+      if (lua_tothread(L, -1) == co)
+        return luaL_error(L, "cannot close main thread");
+      lua_closethread(co, L);  /* close itself */
+      lua_assert(0);  /* previous call does not return */
+      return 0;
     default:  /* normal or running coroutine */
       return luaL_error(L, "cannot close a %s coroutine", statname[status]);
   }
diff --git a/lctype.c b/lctype.c
index 95422809..b1a43e44 100644
--- a/lctype.c
+++ b/lctype.c
@@ -18,7 +18,7 @@
 
 
 #if defined (LUA_UCID)          /* accept UniCode IDentifiers? */
-/* consider all non-ascii codepoints to be alphabetic */
+/* consider all non-ASCII codepoints to be alphabetic */
 #define NONA            0x01
 #else
 #define NONA            0x00    /* default */
diff --git a/ldebug.c b/ldebug.c
index 258a4394..9110f437 100644
--- a/ldebug.c
+++ b/ldebug.c
@@ -817,16 +817,15 @@ l_noret luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
 /* add src:line information to 'msg' */
 const char *luaG_addinfo (lua_State *L, const char *msg, TString *src,
                                         int line) {
-  char buff[LUA_IDSIZE];
-  if (src) {
+  if (src == NULL)  /* no debug information? */
+    return luaO_pushfstring(L, "?:?: %s", msg);
+  else {
+    char buff[LUA_IDSIZE];
     size_t idlen;
     const char *id = getlstr(src, idlen);
     luaO_chunkid(buff, id, idlen);
+    return luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
   }
-  else {  /* no source available; use "?" instead */
-    buff[0] = '?'; buff[1] = '\0';
-  }
-  return luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
 }
 
 
@@ -852,12 +851,8 @@ l_noret luaG_runerror (lua_State *L, const char *fmt, ...) {
   const char *msg;
   va_list argp;
   luaC_checkGC(L);  /* error message uses memory */
-  va_start(argp, fmt);
-  msg = luaO_pushvfstring(L, fmt, argp);  /* format message */
-  va_end(argp);
-  if (msg == NULL)  /* no memory to format message? */
-    luaD_throw(L, LUA_ERRMEM);
-  else if (isLua(ci)) {  /* Lua function? */
+  pushvfstring(L, argp, fmt, msg);
+  if (isLua(ci)) {  /* Lua function? */
     /* add source:line information */
     luaG_addinfo(L, msg, ci_func(ci)->p->source, getcurrentline(ci));
     setobjs2s(L, L->top.p - 2, L->top.p - 1);  /* remove 'msg' */
diff --git a/ldo.c b/ldo.c
index 3e5c7504..f232b588 100644
--- a/ldo.c
+++ b/ldo.c
@@ -139,6 +139,16 @@ l_noret luaD_throw (lua_State *L, TStatus errcode) {
 }
 
 
+l_noret luaD_throwbaselevel (lua_State *L, TStatus errcode) {
+  if (L->errorJmp) {
+    /* unroll error entries up to the first level */
+    while (L->errorJmp->previous != NULL)
+      L->errorJmp = L->errorJmp->previous;
+  }
+  luaD_throw(L, errcode);
+}
+
+
 TStatus luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) {
   l_uint32 oldnCcalls = L->nCcalls;
   struct lua_longjmp lj;
@@ -164,6 +174,20 @@ TStatus luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) {
 #define STACKERRSPACE   200
 
 
+/*
+** LUAI_MAXSTACK limits the size of the Lua stack.
+** It must fit into INT_MAX/2.
+*/
+
+#if !defined(LUAI_MAXSTACK)
+#if 1000000 < (INT_MAX / 2)
+#define LUAI_MAXSTACK           1000000
+#else
+#define LUAI_MAXSTACK           (INT_MAX / 2u)
+#endif
+#endif
+
+
 /* maximum stack size that respects size_t */
 #define MAXSTACK_BYSIZET  ((MAX_SIZET / sizeof(StackValue)) - STACKERRSPACE)
 
@@ -513,7 +537,7 @@ l_sinline void genmoveresults (lua_State *L, StkId res, int nres,
 ** to 'res'.  Handle most typical cases (zero results for commands,
 ** one result for expressions, multiple results for tail calls/single
 ** parameters) separated. The flag CIST_TBC in 'fwanted', if set,
-** forces the swicth to go to the default case.
+** forces the switch to go to the default case.
 */
 l_sinline void moveresults (lua_State *L, StkId res, int nres,
                                           l_uint32 fwanted) {
diff --git a/ldo.h b/ldo.h
index 465f4fb8..2d4ca8be 100644
--- a/ldo.h
+++ b/ldo.h
@@ -91,6 +91,7 @@ LUAI_FUNC void luaD_shrinkstack (lua_State *L);
 LUAI_FUNC void luaD_inctop (lua_State *L);
 
 LUAI_FUNC l_noret luaD_throw (lua_State *L, TStatus errcode);
+LUAI_FUNC l_noret luaD_throwbaselevel (lua_State *L, TStatus errcode);
 LUAI_FUNC TStatus luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud);
 
 #endif
diff --git a/ldump.c b/ldump.c
index d8fca317..a75b20d2 100644
--- a/ldump.c
+++ b/ldump.c
@@ -31,7 +31,7 @@ typedef struct {
   int strip;
   int status;
   Table *h;  /* table to track saved strings */
-  lua_Integer nstr;  /* counter for counting saved strings */
+  lua_Unsigned nstr;  /* counter for counting saved strings */
 } DumpState;
 
 
@@ -87,12 +87,12 @@ static void dumpByte (DumpState *D, int y) {
 ** size for 'dumpVarint' buffer: each byte can store up to 7 bits.
 ** (The "+6" rounds up the division.)
 */
-#define DIBS    ((l_numbits(size_t) + 6) / 7)
+#define DIBS    ((l_numbits(lua_Unsigned) + 6) / 7)
 
 /*
 ** Dumps an unsigned integer using the MSB Varint encoding
 */
-static void dumpVarint (DumpState *D, size_t x) {
+static void dumpVarint (DumpState *D, lua_Unsigned x) {
   lu_byte buff[DIBS];
   unsigned n = 1;
   buff[DIBS - 1] = x & 0x7f;  /* fill least-significant byte */
@@ -103,12 +103,13 @@ static void dumpVarint (DumpState *D, size_t x) {
 
 
 static void dumpSize (DumpState *D, size_t sz) {
-  dumpVarint(D, sz);
+  dumpVarint(D, cast(lua_Unsigned, sz));
 }
 
+
 static void dumpInt (DumpState *D, int x) {
   lua_assert(x >= 0);
-  dumpVarint(D, cast(size_t, x));
+  dumpVarint(D, cast_uint(x));
 }
 
 
@@ -117,8 +118,16 @@ static void dumpNumber (DumpState *D, lua_Number x) {
 }
 
 
+/*
+** Signed integers are coded to keep small values small. (Coding -1 as
+** 0xfff...fff would use too many bytes to save a quite common value.)
+** A non-negative x is coded as 2x; a negative x is coded as -2x - 1.
+** (0 => 0; -1 => 1; 1 => 2; -2 => 3; 2 => 4; ...)
+*/
 static void dumpInteger (DumpState *D, lua_Integer x) {
-  dumpVar(D, x);
+  lua_Unsigned cx = (x >= 0) ? 2u * l_castS2U(x)
+                             : (2u * ~l_castS2U(x)) + 1;
+  dumpVarint(D, cx);
 }
 
 
@@ -136,8 +145,8 @@ static void dumpString (DumpState *D, TString *ts) {
     TValue idx;
     int tag = luaH_getstr(D->h, ts, &idx);
     if (!tagisempty(tag)) {  /* string already saved? */
-      dumpSize(D, 1);  /* reuse a saved string */
-      dumpSize(D, cast_sizet(ivalue(&idx)));  /* index of saved string */
+      dumpVarint(D, 1);  /* reuse a saved string */
+      dumpVarint(D, l_castS2U(ivalue(&idx)));  /* index of saved string */
     }
     else {  /* must write and save the string */
       TValue key, value;  /* to save the string in the hash */
@@ -147,7 +156,7 @@ static void dumpString (DumpState *D, TString *ts) {
       dumpVector(D, s, size + 1);  /* include ending '\0' */
       D->nstr++;  /* one more saved string */
       setsvalue(D->L, &key, ts);  /* the string is the key */
-      setivalue(&value, D->nstr);  /* its index is the value */
+      setivalue(&value, l_castU2S(D->nstr));  /* its index is the value */
       luaH_set(D->L, D->h, &key, &value);  /* h[ts] = nstr */
       /* integer value does not need barrier */
     }
diff --git a/lgc.c b/lgc.c
index cada07d9..bbaa5ff7 100644
--- a/lgc.c
+++ b/lgc.c
@@ -126,7 +126,6 @@ static l_mem objsize (GCObject *o) {
       CClosure *cl = gco2ccl(o);
       res = sizeCclosure(cl->nupvalues);
       break;
-      break;
     }
     case LUA_VUSERDATA: {
       Udata *u = gco2u(o);
@@ -465,6 +464,8 @@ static void restartcollection (global_State *g) {
 ** TOUCHED1 objects need to be in the list. TOUCHED2 doesn't need to go
 ** back to a gray list, but then it must become OLD. (That is what
 ** 'correctgraylist' does when it finds a TOUCHED2 object.)
+** This function is a no-op in incremental mode, as objects cannot be
+** marked as touched in that mode.
 */
 static void genlink (global_State *g, GCObject *o) {
   lua_assert(isblack(o));
@@ -480,7 +481,8 @@ static void genlink (global_State *g, GCObject *o) {
 ** Traverse a table with weak values and link it to proper list. During
 ** propagate phase, keep it in 'grayagain' list, to be revisited in the
 ** atomic phase. In the atomic phase, if table has any white value,
-** put it in 'weak' list, to be cleared.
+** put it in 'weak' list, to be cleared; otherwise, call 'genlink'
+** to check table age in generational mode.
 */
 static void traverseweakvalue (global_State *g, Table *h) {
   Node *n, *limit = gnodelast(h);
@@ -501,6 +503,8 @@ static void traverseweakvalue (global_State *g, Table *h) {
     linkgclist(h, g->grayagain);  /* must retraverse it in atomic phase */
   else if (hasclears)
       linkgclist(h, g->weak);  /* has to be cleared later */
+  else
+    genlink(g, obj2gco(h));
 }
 
 
@@ -585,25 +589,41 @@ static void traversestrongtable (global_State *g, Table *h) {
 }
 
 
-static l_mem traversetable (global_State *g, Table *h) {
-  const char *weakkey, *weakvalue;
+/*
+** (result & 1) iff weak values; (result & 2) iff weak keys.
+*/
+static int getmode (global_State *g, Table *h) {
   const TValue *mode = gfasttm(g, h->metatable, TM_MODE);
-  TString *smode;
+  if (mode == NULL || !ttisshrstring(mode))
+    return 0;  /* ignore non-(short)string modes */
+  else {
+    const char *smode = getshrstr(tsvalue(mode));
+    const char *weakkey = strchr(smode, 'k');
+    const char *weakvalue = strchr(smode, 'v');
+    return ((weakkey != NULL) << 1) | (weakvalue != NULL);
+  }
+}
+
+
+static l_mem traversetable (global_State *g, Table *h) {
   markobjectN(g, h->metatable);
-  if (mode && ttisshrstring(mode) &&  /* is there a weak mode? */
-      (cast_void(smode = tsvalue(mode)),
-       cast_void(weakkey = strchr(getshrstr(smode), 'k')),
-       cast_void(weakvalue = strchr(getshrstr(smode), 'v')),
-       (weakkey || weakvalue))) {  /* is really weak? */
-    if (!weakkey)  /* strong keys? */
+  switch (getmode(g, h)) {
+    case 0:  /* not weak */
+      traversestrongtable(g, h);
+      break;
+    case 1:  /* weak values */
       traverseweakvalue(g, h);
-    else if (!weakvalue)  /* strong values? */
+      break;
+    case 2:  /* weak keys */
       traverseephemeron(g, h, 0);
-    else  /* all weak */
-      linkgclist(h, g->allweak);  /* nothing to traverse now */
+      break;
+    case 3:  /* all weak; nothing to traverse */
+      if (g->gcstate == GCSpropagate)
+        linkgclist(h, g->grayagain);  /* must visit again its metatable */
+      else
+        linkgclist(h, g->allweak);  /* must clear collected entries */
+      break;
   }
-  else  /* not weak */
-    traversestrongtable(g, h);
   return 1 + 2*sizenode(h) + h->asize;
 }
 
diff --git a/llex.c b/llex.c
index 4b5a1f75..f8bb3ea4 100644
--- a/llex.c
+++ b/llex.c
@@ -44,7 +44,7 @@
 /* ORDER RESERVED */
 static const char *const luaX_tokens [] = {
     "and", "break", "do", "else", "elseif",
-    "end", "false", "for", "function", "goto", "if",
+    "end", "false", "for", "function", "global", "goto", "if",
     "in", "local", "nil", "not", "or", "repeat",
     "return", "then", "true", "until", "while",
     "//", "..", "...", "==", ">=", "<=", "~=",
@@ -184,7 +184,15 @@ void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source,
   ls->linenumber = 1;
   ls->lastline = 1;
   ls->source = source;
-  ls->envn = luaS_newliteral(L, LUA_ENV);  /* get env name */
+  /* all three strings here ("_ENV", "break", "global") were fixed,
+     so they cannot be collected */
+  ls->envn = luaS_newliteral(L, LUA_ENV);  /* get env string */
+  ls->brkn = luaS_newliteral(L, "break");  /* get "break" string */
+#if defined(LUA_COMPAT_GLOBAL)
+  /* compatibility mode: "global" is not a reserved word */
+  ls->glbn = luaS_newliteral(L, "global");  /* get "global" string */
+  ls->glbn->extra = 0;  /* mark it as not reserved */
+#endif
   luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER);  /* initialize buffer */
 }
 
@@ -354,12 +362,12 @@ static int readhexaesc (LexState *ls) {
 ** for error reporting in case of errors; 'i' counts the number of
 ** saved characters, so that they can be removed if case of success.
 */
-static unsigned long readutf8esc (LexState *ls) {
-  unsigned long r;
+static l_uint32 readutf8esc (LexState *ls) {
+  l_uint32 r;
   int i = 4;  /* number of chars to be removed: start with #"\u{X" */
   save_and_next(ls);  /* skip 'u' */
   esccheck(ls, ls->current == '{', "missing '{'");
-  r = cast_ulong(gethexa(ls));  /* must have at least one digit */
+  r = cast_uint(gethexa(ls));  /* must have at least one digit */
   while (cast_void(save_and_next(ls)), lisxdigit(ls->current)) {
     i++;
     esccheck(ls, r <= (0x7FFFFFFFu >> 4), "UTF-8 value too large");
diff --git a/llex.h b/llex.h
index c3500ef6..37016e8a 100644
--- a/llex.h
+++ b/llex.h
@@ -33,8 +33,8 @@ enum RESERVED {
   /* terminal symbols denoted by reserved words */
   TK_AND = FIRST_RESERVED, TK_BREAK,
   TK_DO, TK_ELSE, TK_ELSEIF, TK_END, TK_FALSE, TK_FOR, TK_FUNCTION,
-  TK_GOTO, TK_IF, TK_IN, TK_LOCAL, TK_NIL, TK_NOT, TK_OR, TK_REPEAT,
-  TK_RETURN, TK_THEN, TK_TRUE, TK_UNTIL, TK_WHILE,
+  TK_GLOBAL, TK_GOTO, TK_IF, TK_IN, TK_LOCAL, TK_NIL, TK_NOT, TK_OR,
+  TK_REPEAT, TK_RETURN, TK_THEN, TK_TRUE, TK_UNTIL, TK_WHILE,
   /* other terminal symbols */
   TK_IDIV, TK_CONCAT, TK_DOTS, TK_EQ, TK_GE, TK_LE, TK_NE,
   TK_SHL, TK_SHR,
@@ -75,6 +75,8 @@ typedef struct LexState {
   struct Dyndata *dyd;  /* dynamic structures used by the parser */
   TString *source;  /* current source name */
   TString *envn;  /* environment variable name */
+  TString *brkn;  /* "break" name (used as a label) */
+  TString *glbn;  /* "global" name (when not a reserved word) */
 } LexState;
 
 
diff --git a/llimits.h b/llimits.h
index 710dc1b4..223b5e6c 100644
--- a/llimits.h
+++ b/llimits.h
@@ -137,13 +137,15 @@ typedef LUAI_UACINT l_uacInt;
 #define cast_voidp(i)   cast(void *, (i))
 #define cast_num(i)     cast(lua_Number, (i))
 #define cast_int(i)     cast(int, (i))
+#define cast_short(i)   cast(short, (i))
 #define cast_uint(i)    cast(unsigned int, (i))
-#define cast_ulong(i)   cast(unsigned long, (i))
 #define cast_byte(i)    cast(lu_byte, (i))
 #define cast_uchar(i)   cast(unsigned char, (i))
 #define cast_char(i)    cast(char, (i))
 #define cast_charp(i)   cast(char *, (i))
 #define cast_sizet(i)   cast(size_t, (i))
+#define cast_Integer(i) cast(lua_Integer, (i))
+#define cast_Inst(i)    cast(Instruction, (i))
 
 
 /* cast a signed lua_Integer to lua_Unsigned */
diff --git a/loadlib.c b/loadlib.c
index 5f0c1702..8d2e68e2 100644
--- a/loadlib.c
+++ b/loadlib.c
@@ -307,6 +307,16 @@ static void setpath (lua_State *L, const char *fieldname,
 
 
 /*
+** External strings created by DLLs may need the DLL code to be
+** deallocated. This implies that a DLL can only be unloaded after all
+** its strings were deallocated. To ensure that, we create a 'library
+** string' to represent each DLL, and when this string is deallocated
+** it closes its corresponding DLL.
+** (The string itself is irrelevant; its userdata is the DLL pointer.)
+*/
+
+
+/*
 ** return registry.CLIBS[path]
 */
 static void *checkclib (lua_State *L, const char *path) {
@@ -320,34 +330,41 @@ static void *checkclib (lua_State *L, const char *path) {
 
 
 /*
-** registry.CLIBS[path] = plib        -- for queries
-** registry.CLIBS[#CLIBS + 1] = plib  -- also keep a list of all libraries
+** Deallocate function for library strings.
+** Unload the DLL associated with the string being deallocated.
 */
-static void addtoclib (lua_State *L, const char *path, void *plib) {
-  lua_getfield(L, LUA_REGISTRYINDEX, CLIBS);
-  lua_pushlightuserdata(L, plib);
-  lua_pushvalue(L, -1);
-  lua_setfield(L, -3, path);  /* CLIBS[path] = plib */
-  lua_rawseti(L, -2, luaL_len(L, -2) + 1);  /* CLIBS[#CLIBS + 1] = plib */
-  lua_pop(L, 1);  /* pop CLIBS table */
+static void *freelib (void *ud, void *ptr, size_t osize, size_t nsize) {
+  /* string itself is irrelevant and static */
+  (void)ptr; (void)osize; (void)nsize;
+  lsys_unloadlib(ud);  /* unload library represented by the string */
+  return NULL;
 }
 
 
 /*
-** __gc tag method for CLIBS table: calls 'lsys_unloadlib' for all lib
-** handles in list CLIBS
+** Create a library string that, when deallocated, will unload 'plib'
 */
-static int gctm (lua_State *L) {
-  lua_Integer n = luaL_len(L, 1);
-  for (; n >= 1; n--) {  /* for each handle, in reverse order */
-    lua_rawgeti(L, 1, n);  /* get handle CLIBS[n] */
-    lsys_unloadlib(lua_touserdata(L, -1));
-    lua_pop(L, 1);  /* pop handle */
-  }
-  return 0;
+static void createlibstr (lua_State *L, void *plib) {
+  /* common content for all library strings */
+  static const char dummy[] = "01234567890";
+  lua_pushexternalstring(L, dummy, sizeof(dummy) - 1, freelib, plib);
 }
 
 
+/*
+** registry.CLIBS[path] = plib          -- for queries.
+** Also create a reference to strlib, so that the library string will
+** only be collected when registry.CLIBS is collected.
+*/
+static void addtoclib (lua_State *L, const char *path, void *plib) {
+  lua_getfield(L, LUA_REGISTRYINDEX, CLIBS);
+  lua_pushlightuserdata(L, plib);
+  lua_setfield(L, -2, path);  /* CLIBS[path] = plib */
+  createlibstr(L, plib);
+  luaL_ref(L, -2);  /* keep library string in CLIBS */
+  lua_pop(L, 1);  /* pop CLIBS table */
+}
+
 
 /* error codes for 'lookforfunc' */
 #define ERRLIB          1
@@ -361,8 +378,8 @@ static int gctm (lua_State *L) {
 ** Then, if 'sym' is '*', return true (as library has been loaded).
 ** Otherwise, look for symbol 'sym' in the library and push a
 ** C function with that symbol.
-** Return 0 and 'true' or a function in the stack; in case of
-** errors, return an error code and an error message in the stack.
+** Return 0 with 'true' or a function in the stack; in case of
+** errors, return an error code with an error message in the stack.
 */
 static int lookforfunc (lua_State *L, const char *path, const char *sym) {
   void *reg = checkclib(L, path);  /* check loaded C libraries */
@@ -704,21 +721,9 @@ static void createsearcherstable (lua_State *L) {
 }
 
 
-/*
-** create table CLIBS to keep track of loaded C libraries,
-** setting a finalizer to close all libraries when closing state.
-*/
-static void createclibstable (lua_State *L) {
-  luaL_getsubtable(L, LUA_REGISTRYINDEX, CLIBS);  /* create CLIBS table */
-  lua_createtable(L, 0, 1);  /* create metatable for CLIBS */
-  lua_pushcfunction(L, gctm);
-  lua_setfield(L, -2, "__gc");  /* set finalizer for CLIBS table */
-  lua_setmetatable(L, -2);
-}
-
-
 LUAMOD_API int luaopen_package (lua_State *L) {
-  createclibstable(L);
+  luaL_getsubtable(L, LUA_REGISTRYINDEX, CLIBS);  /* create CLIBS table */
+  lua_pop(L, 1);  /* will not use it now */
   luaL_newlib(L, pk_funcs);  /* create 'package' table */
   createsearcherstable(L);
   /* set paths */
diff --git a/lobject.c b/lobject.c
index 68566a2b..b558cfe0 100644
--- a/lobject.c
+++ b/lobject.c
@@ -31,7 +31,8 @@
 
 
 /*
-** Computes ceil(log2(x))
+** Computes ceil(log2(x)), which is the smallest integer n such that
+** x <= (1 << n).
 */
 lu_byte luaO_ceillog2 (unsigned int x) {
   static const lu_byte log_2[256] = {  /* log_2[i - 1] = ceil(log2(i)) */
@@ -382,10 +383,10 @@ size_t luaO_str2num (const char *s, TValue *o) {
 }
 
 
-int luaO_utf8esc (char *buff, unsigned long x) {
+int luaO_utf8esc (char *buff, l_uint32 x) {
   int n = 1;  /* number of bytes put in buffer (backwards) */
   lua_assert(x <= 0x7FFFFFFFu);
-  if (x < 0x80)  /* ascii? */
+  if (x < 0x80)  /* ASCII? */
     buff[UTF8BUFFSZ - 1] = cast_char(x);
   else {  /* need continuation bytes */
     unsigned int mfb = 0x3f;  /* maximum that fits in first byte */
@@ -618,7 +619,7 @@ const char *luaO_pushvfstring (lua_State *L, const char *fmt, va_list argp) {
       }
       case 'I': {  /* a 'lua_Integer' */
         TValue num;
-        setivalue(&num, cast(lua_Integer, va_arg(argp, l_uacInt)));
+        setivalue(&num, cast_Integer(va_arg(argp, l_uacInt)));
         addnum2buff(&buff, &num);
         break;
       }
@@ -637,7 +638,8 @@ const char *luaO_pushvfstring (lua_State *L, const char *fmt, va_list argp) {
       }
       case 'U': {  /* an 'unsigned long' as a UTF-8 sequence */
         char bf[UTF8BUFFSZ];
-        int len = luaO_utf8esc(bf, va_arg(argp, unsigned long));
+        unsigned long arg = va_arg(argp, unsigned long);
+        int len = luaO_utf8esc(bf, cast(l_uint32, arg));
         addstr2buff(&buff, bf + UTF8BUFFSZ - len, cast_uint(len));
         break;
       }
diff --git a/lobject.h b/lobject.h
index 8c06a224..cc3dd370 100644
--- a/lobject.h
+++ b/lobject.h
@@ -418,6 +418,7 @@ typedef struct TString {
 
 
 #define strisshr(ts)    ((ts)->shrlen >= 0)
+#define isextstr(ts)    (ttislngstring(ts) && tsvalue(ts)->shrlen != LSTRREG)
 
 
 /*
@@ -822,7 +823,16 @@ typedef struct Table {
 /* size of buffer for 'luaO_utf8esc' function */
 #define UTF8BUFFSZ      8
 
-LUAI_FUNC int luaO_utf8esc (char *buff, unsigned long x);
+
+/* macro to call 'luaO_pushvfstring' correctly */
+#define pushvfstring(L, argp, fmt, msg) \
+  { va_start(argp, fmt); \
+  msg = luaO_pushvfstring(L, fmt, argp); \
+  va_end(argp); \
+  if (msg == NULL) luaD_throw(L, LUA_ERRMEM);  /* only after 'va_end' */ }
+
+
+LUAI_FUNC int luaO_utf8esc (char *buff, l_uint32 x);
 LUAI_FUNC lu_byte luaO_ceillog2 (unsigned int x);
 LUAI_FUNC lu_byte luaO_codeparam (unsigned int p);
 LUAI_FUNC l_mem luaO_applyparam (lu_byte p, l_mem x);
diff --git a/lopcodes.h b/lopcodes.h
index 7511eb22..97870038 100644
--- a/lopcodes.h
+++ b/lopcodes.h
@@ -126,14 +126,14 @@ enum OpMode {iABC, ivABC, iABx, iAsBx, iAx, isJ};
 
 #define GET_OPCODE(i)   (cast(OpCode, ((i)>>POS_OP) & MASK1(SIZE_OP,0)))
 #define SET_OPCODE(i,o) ((i) = (((i)&MASK0(SIZE_OP,POS_OP)) | \
-                ((cast(Instruction, o)<<POS_OP)&MASK1(SIZE_OP,POS_OP))))
+                ((cast_Inst(o)<<POS_OP)&MASK1(SIZE_OP,POS_OP))))
 
 #define checkopm(i,m)   (getOpMode(GET_OPCODE(i)) == m)
 
 
 #define getarg(i,pos,size)      (cast_int(((i)>>(pos)) & MASK1(size,0)))
 #define setarg(i,v,pos,size)    ((i) = (((i)&MASK0(size,pos)) | \
-                ((cast(Instruction, v)<<pos)&MASK1(size,pos))))
+                ((cast_Inst(v)<<pos)&MASK1(size,pos))))
 
 #define GETARG_A(i)     getarg(i, POS_A, SIZE_A)
 #define SETARG_A(i,v)   setarg(i, v, POS_A, SIZE_A)
@@ -174,28 +174,28 @@ enum OpMode {iABC, ivABC, iABx, iAsBx, iAx, isJ};
         setarg(i, cast_uint((j)+OFFSET_sJ), POS_sJ, SIZE_sJ)
 
 
-#define CREATE_ABCk(o,a,b,c,k)  ((cast(Instruction, o)<<POS_OP) \
-                        | (cast(Instruction, a)<<POS_A) \
-                        | (cast(Instruction, b)<<POS_B) \
-                        | (cast(Instruction, c)<<POS_C) \
-                        | (cast(Instruction, k)<<POS_k))
+#define CREATE_ABCk(o,a,b,c,k)  ((cast_Inst(o)<<POS_OP) \
+                        | (cast_Inst(a)<<POS_A) \
+                        | (cast_Inst(b)<<POS_B) \
+                        | (cast_Inst(c)<<POS_C) \
+                        | (cast_Inst(k)<<POS_k))
 
-#define CREATE_vABCk(o,a,b,c,k) ((cast(Instruction, o)<<POS_OP) \
-                        | (cast(Instruction, a)<<POS_A) \
-                        | (cast(Instruction, b)<<POS_vB) \
-                        | (cast(Instruction, c)<<POS_vC) \
-                        | (cast(Instruction, k)<<POS_k))
+#define CREATE_vABCk(o,a,b,c,k) ((cast_Inst(o)<<POS_OP) \
+                        | (cast_Inst(a)<<POS_A) \
+                        | (cast_Inst(b)<<POS_vB) \
+                        | (cast_Inst(c)<<POS_vC) \
+                        | (cast_Inst(k)<<POS_k))
 
-#define CREATE_ABx(o,a,bc)      ((cast(Instruction, o)<<POS_OP) \
-                        | (cast(Instruction, a)<<POS_A) \
-                        | (cast(Instruction, bc)<<POS_Bx))
+#define CREATE_ABx(o,a,bc)      ((cast_Inst(o)<<POS_OP) \
+                        | (cast_Inst(a)<<POS_A) \
+                        | (cast_Inst(bc)<<POS_Bx))
 
-#define CREATE_Ax(o,a)          ((cast(Instruction, o)<<POS_OP) \
-                        | (cast(Instruction, a)<<POS_Ax))
+#define CREATE_Ax(o,a)          ((cast_Inst(o)<<POS_OP) \
+                        | (cast_Inst(a)<<POS_Ax))
 
-#define CREATE_sJ(o,j,k)        ((cast(Instruction, o) << POS_OP) \
-                        | (cast(Instruction, j) << POS_sJ) \
-                        | (cast(Instruction, k) << POS_k))
+#define CREATE_sJ(o,j,k)        ((cast_Inst(o) << POS_OP) \
+                        | (cast_Inst(j) << POS_sJ) \
+                        | (cast_Inst(k) << POS_k))
 
 
 #if !defined(MAXINDEXRK)  /* (for debugging only) */
@@ -254,7 +254,7 @@ OP_SETTABLE,/*	A B C	R[A][R[B]] := RK(C)				*/
 OP_SETI,/*      A B C   R[A][B] := RK(C)                                */
 OP_SETFIELD,/*  A B C   R[A][K[B]:shortstring] := RK(C)                 */
 
-OP_NEWTABLE,/*  A B C k R[A] := {}                                      */
+OP_NEWTABLE,/*  A vB vC k       R[A] := {}                              */
 
 OP_SELF,/*      A B C   R[A+1] := R[B]; R[A] := R[B][K[C]:shortstring]  */
 
@@ -378,9 +378,9 @@ OP_EXTRAARG/*	Ax	extra (larger) argument for previous opcode	*/
   real C = EXTRAARG _ C (the bits of EXTRAARG concatenated with the
   bits of C).
 
-  (*) In OP_NEWTABLE, B is log2 of the hash size (which is always a
+  (*) In OP_NEWTABLE, vB is log2 of the hash size (which is always a
   power of 2) plus 1, or zero for size zero. If not k, the array size
-  is C. Otherwise, the array size is EXTRAARG _ C.
+  is vC. Otherwise, the array size is EXTRAARG _ vC.
 
   (*) For comparisons, k specifies what condition the test should accept
   (true or false).
diff --git a/loslib.c b/loslib.c
index 4623ad5e..3f605028 100644
--- a/loslib.c
+++ b/loslib.c
@@ -273,7 +273,7 @@ static int getfield (lua_State *L, const char *key, int d, int delta) {
 
 
 static const char *checkoption (lua_State *L, const char *conv,
-                                ptrdiff_t convlen, char *buff) {
+                                size_t convlen, char *buff) {
   const char *option = LUA_STRFTIMEOPTIONS;
   unsigned oplen = 1;  /* length of options being checked */
   for (; *option != '\0' && oplen <= convlen; option += oplen) {
@@ -333,7 +333,8 @@ static int os_date (lua_State *L) {
         size_t reslen;
         char *buff = luaL_prepbuffsize(&b, SIZETIMEFMT);
         s++;  /* skip '%' */
-        s = checkoption(L, s, se - s, cc + 1);  /* copy specifier to 'cc' */
+        /* copy specifier to 'cc' */
+        s = checkoption(L, s, ct_diff2sz(se - s), cc + 1);
         reslen = strftime(buff, SIZETIMEFMT, cc, stm);
         luaL_addsize(&b, reslen);
       }
diff --git a/lparser.c b/lparser.c
index 380e45f5..dde0b6d5 100644
--- a/lparser.c
+++ b/lparser.c
@@ -30,8 +30,8 @@
 
 
 
-/* maximum number of local variables per function (must be smaller
-   than 250, due to the bytecode format) */
+/* maximum number of variable declarations per function (must be
+   smaller than 250, due to the bytecode format) */
 #define MAXVARS         200
 
 
@@ -50,7 +50,7 @@ typedef struct BlockCnt {
   struct BlockCnt *previous;  /* chain */
   int firstlabel;  /* index of first label in this block */
   int firstgoto;  /* index of first pending goto in this block */
-  lu_byte nactvar;  /* # active locals outside the block */
+  short nactvar;  /* number of active declarations at block entry */
   lu_byte upval;  /* true if some variable in the block is an upvalue */
   lu_byte isloop;  /* 1 if 'block' is a loop; 2 if it has pending breaks */
   lu_byte insidetbc;  /* true if inside the scope of a to-be-closed var. */
@@ -188,18 +188,16 @@ static short registerlocalvar (LexState *ls, FuncState *fs,
 
 
 /*
-** Create a new local variable with the given 'name' and given 'kind'.
+** Create a new variable with the given 'name' and given 'kind'.
 ** Return its index in the function.
 */
-static int new_localvarkind (LexState *ls, TString *name, lu_byte kind) {
+static int new_varkind (LexState *ls, TString *name, lu_byte kind) {
   lua_State *L = ls->L;
   FuncState *fs = ls->fs;
   Dyndata *dyd = ls->dyd;
   Vardesc *var;
-  luaY_checklimit(fs, dyd->actvar.n + 1 - fs->firstlocal,
-                 MAXVARS, "local variables");
   luaM_growvector(L, dyd->actvar.arr, dyd->actvar.n + 1,
-                  dyd->actvar.size, Vardesc, SHRT_MAX, "local variables");
+             dyd->actvar.size, Vardesc, SHRT_MAX, "variable declarations");
   var = &dyd->actvar.arr[dyd->actvar.n++];
   var->vd.kind = kind;  /* default */
   var->vd.name = name;
@@ -211,7 +209,7 @@ static int new_localvarkind (LexState *ls, TString *name, lu_byte kind) {
 ** Create a new local variable with the given 'name' and regular kind.
 */
 static int new_localvar (LexState *ls, TString *name) {
-  return new_localvarkind(ls, name, VDKREG);
+  return new_varkind(ls, name, VDKREG);
 }
 
 #define new_localvarliteral(ls,v) \
@@ -238,7 +236,7 @@ static Vardesc *getlocalvardesc (FuncState *fs, int vidx) {
 static lu_byte reglevel (FuncState *fs, int nvar) {
   while (nvar-- > 0) {
     Vardesc *vd = getlocalvardesc(fs, nvar);  /* get previous variable */
-    if (vd->vd.kind != RDKCTC)  /* is in a register? */
+    if (varinreg(vd))  /* is in a register? */
       return cast_byte(vd->vd.ridx + 1);
   }
   return 0;  /* no variables in registers */
@@ -259,7 +257,7 @@ lu_byte luaY_nvarstack (FuncState *fs) {
 */
 static LocVar *localdebuginfo (FuncState *fs, int vidx) {
   Vardesc *vd = getlocalvardesc(fs,  vidx);
-  if (vd->vd.kind == RDKCTC)
+  if (!varinreg(vd))
     return NULL;  /* no debug info. for constants */
   else {
     int idx = vd->vd.pidx;
@@ -275,7 +273,7 @@ static LocVar *localdebuginfo (FuncState *fs, int vidx) {
 static void init_var (FuncState *fs, expdesc *e, int vidx) {
   e->f = e->t = NO_JUMP;
   e->k = VLOCAL;
-  e->u.var.vidx = cast(unsigned short, vidx);
+  e->u.var.vidx = cast_short(vidx);
   e->u.var.ridx = getlocalvardesc(fs, vidx)->vd.ridx;
 }
 
@@ -303,14 +301,18 @@ static void check_readonly (LexState *ls, expdesc *e) {
         varname = up->name;
       break;
     }
+    case VINDEXUP: case VINDEXSTR: case VINDEXED: {  /* global variable */
+      if (e->u.ind.ro)  /* read-only? */
+        varname = tsvalue(&fs->f->k[e->u.ind.keystr]);
+      break;
+    }
     default:
-      return;  /* other cases cannot be read-only */
-  }
-  if (varname) {
-    const char *msg = luaO_pushfstring(ls->L,
-       "attempt to assign to const variable '%s'", getstr(varname));
-    luaK_semerror(ls, msg);  /* error */
+      lua_assert(e->k == VINDEXI);  /* this one doesn't need any check */
+      return;  /* integer index cannot be read-only */
   }
+  if (varname)
+    luaK_semerror(ls, "attempt to assign to const variable '%s'",
+                      getstr(varname));
 }
 
 
@@ -326,6 +328,7 @@ static void adjustlocalvars (LexState *ls, int nvars) {
     Vardesc *var = getlocalvardesc(fs, vidx);
     var->vd.ridx = cast_byte(reglevel++);
     var->vd.pidx = registerlocalvar(ls, fs, var->vd.name);
+    luaY_checklimit(fs, reglevel, MAXVARS, "local variables");
   }
 }
 
@@ -392,18 +395,38 @@ static int newupvalue (FuncState *fs, TString *name, expdesc *v) {
 
 
 /*
-** Look for an active local variable with the name 'n' in the
+** Look for an active variable with the name 'n' in the
 ** function 'fs'. If found, initialize 'var' with it and return
-** its expression kind; otherwise return -1.
+** its expression kind; otherwise return -1. While searching,
+** var->u.info==-1 means that the preambular global declaration is
+** active (the default while there is no other global declaration);
+** var->u.info==-2 means there is no active collective declaration
+** (some previous global declaration but no collective declaration);
+** and var->u.info>=0 points to the inner-most (the first one found)
+** collective declaration, if there is one.
 */
 static int searchvar (FuncState *fs, TString *n, expdesc *var) {
   int i;
   for (i = cast_int(fs->nactvar) - 1; i >= 0; i--) {
     Vardesc *vd = getlocalvardesc(fs, i);
-    if (eqstr(n, vd->vd.name)) {  /* found? */
+    if (varglobal(vd)) {  /* global declaration? */
+      if (vd->vd.name == NULL) {  /* collective declaration? */
+        if (var->u.info < 0)  /* no previous collective declaration? */
+          var->u.info = fs->firstlocal + i;  /* this is the first one */
+      }
+      else {  /* global name */
+        if (eqstr(n, vd->vd.name)) {  /* found? */
+          init_exp(var, VGLOBAL, fs->firstlocal + i);
+          return VGLOBAL;
+        }
+        else if (var->u.info == -1)  /* active preambular declaration? */
+          var->u.info = -2;  /* invalidate preambular declaration */
+      }
+    }
+    else if (eqstr(n, vd->vd.name)) {  /* found? */
       if (vd->vd.kind == RDKCTC)  /* compile-time constant? */
         init_exp(var, VCONST, fs->firstlocal + i);
-      else  /* real variable */
+      else  /* local variable */
         init_var(fs, var, i);
       return cast_int(var->k);
     }
@@ -442,48 +465,67 @@ static void marktobeclosed (FuncState *fs) {
 ** 'var' as 'void' as a flag.
 */
 static void singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
-  if (fs == NULL)  /* no more levels? */
-    init_exp(var, VVOID, 0);  /* default is global */
-  else {
-    int v = searchvar(fs, n, var);  /* look up locals at current level */
-    if (v >= 0) {  /* found? */
-      if (v == VLOCAL && !base)
-        markupval(fs, var->u.var.vidx);  /* local will be used as an upval */
-    }
-    else {  /* not found as local at current level; try upvalues */
-      int idx = searchupvalue(fs, n);  /* try existing upvalues */
-      if (idx < 0) {  /* not found? */
+  int v = searchvar(fs, n, var);  /* look up variables at current level */
+  if (v >= 0) {  /* found? */
+    if (v == VLOCAL && !base)
+      markupval(fs, var->u.var.vidx);  /* local will be used as an upval */
+  }
+  else {  /* not found at current level; try upvalues */
+    int idx = searchupvalue(fs, n);  /* try existing upvalues */
+    if (idx < 0) {  /* not found? */
+      if (fs->prev != NULL)  /* more levels? */
         singlevaraux(fs->prev, n, var, 0);  /* try upper levels */
-        if (var->k == VLOCAL || var->k == VUPVAL)  /* local or upvalue? */
-          idx  = newupvalue(fs, n, var);  /* will be a new upvalue */
-        else  /* it is a global or a constant */
-          return;  /* don't need to do anything at this level */
-      }
-      init_exp(var, VUPVAL, idx);  /* new or old upvalue */
+      if (var->k == VLOCAL || var->k == VUPVAL)  /* local or upvalue? */
+        idx  = newupvalue(fs, n, var);  /* will be a new upvalue */
+      else  /* it is a global or a constant */
+        return;  /* don't need to do anything at this level */
     }
+    init_exp(var, VUPVAL, idx);  /* new or old upvalue */
   }
 }
 
 
+static void buildglobal (LexState *ls, TString *varname, expdesc *var) {
+  FuncState *fs = ls->fs;
+  expdesc key;
+  init_exp(var, VGLOBAL, -1);  /* global by default */
+  singlevaraux(fs, ls->envn, var, 1);  /* get environment variable */
+  if (var->k == VGLOBAL)
+    luaK_semerror(ls, "_ENV is global when accessing variable '%s'",
+                      getstr(varname));
+  luaK_exp2anyregup(fs, var);  /* _ENV could be a constant */
+  codestring(&key, varname);  /* key is variable name */
+  luaK_indexed(fs, var, &key);  /* 'var' represents _ENV[varname] */
+}
+
+
 /*
 ** Find a variable with the given name 'n', handling global variables
 ** too.
 */
-static void singlevar (LexState *ls, expdesc *var) {
-  TString *varname = str_checkname(ls);
+static void buildvar (LexState *ls, TString *varname, expdesc *var) {
   FuncState *fs = ls->fs;
+  init_exp(var, VGLOBAL, -1);  /* global by default */
   singlevaraux(fs, varname, var, 1);
-  if (var->k == VVOID) {  /* global name? */
-    expdesc key;
-    singlevaraux(fs, ls->envn, var, 1);  /* get environment variable */
-    lua_assert(var->k != VVOID);  /* this one must exist */
-    luaK_exp2anyregup(fs, var);  /* but could be a constant */
-    codestring(&key, varname);  /* key is variable name */
-    luaK_indexed(fs, var, &key);  /* env[varname] */
+  if (var->k == VGLOBAL) {  /* global name? */
+    int info = var->u.info;
+    /* global by default in the scope of a global declaration? */
+    if (info == -2)
+      luaK_semerror(ls, "variable '%s' not declared", getstr(varname));
+    buildglobal(ls, varname, var);
+    if (info != -1 && ls->dyd->actvar.arr[info].vd.kind == GDKCONST)
+      var->u.ind.ro = 1;  /* mark variable as read-only */
+    else  /* anyway must be a global */
+      lua_assert(info == -1 || ls->dyd->actvar.arr[info].vd.kind == GDKREG);
   }
 }
 
 
+static void singlevar (LexState *ls, expdesc *var) {
+  buildvar(ls, str_checkname(ls), var);
+}
+
+
 /*
 ** Adjust the number of results from an expression list 'e' with 'nexps'
 ** expressions to 'nvars' values.
@@ -518,14 +560,14 @@ static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) {
 
 /*
 ** Generates an error that a goto jumps into the scope of some
-** local variable.
+** variable declaration.
 */
 static l_noret jumpscopeerror (LexState *ls, Labeldesc *gt) {
   TString *tsname = getlocalvardesc(ls->fs, gt->nactvar)->vd.name;
-  const char *varname = getstr(tsname);
-  const char *msg = "<goto %s> at line %d jumps into the scope of local '%s'";
-  msg = luaO_pushfstring(ls->L, msg, getstr(gt->name), gt->line, varname);
-  luaK_semerror(ls, msg);  /* raise the error */
+  const char *varname = (tsname != NULL) ? getstr(tsname) : "*";
+  luaK_semerror(ls,
+     "<goto %s> at line %d jumps into the scope of '%s'",
+      getstr(gt->name), gt->line, varname);  /* raise the error */
 }
 
 
@@ -563,7 +605,7 @@ static void closegoto (LexState *ls, int g, Labeldesc *label, int bup) {
 
 /*
 ** Search for an active label with the given name, starting at
-** index 'ilb' (so that it can searh for all labels in current block
+** index 'ilb' (so that it can search for all labels in current block
 ** or all labels in current function).
 */
 static Labeldesc *findlabel (LexState *ls, TString *name, int ilb) {
@@ -630,7 +672,7 @@ static void createlabel (LexState *ls, TString *name, int line, int last) {
 
 
 /*
-** Traverse the pending goto's of the finishing block checking whether
+** Traverse the pending gotos of the finishing block checking whether
 ** each match some label of that block. Those that do not match are
 ** "exported" to the outer block, to be solved there. In particular,
 ** its 'nactvar' is updated with the level of the inner block,
@@ -666,8 +708,9 @@ static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isloop) {
   bl->firstlabel = fs->ls->dyd->label.n;
   bl->firstgoto = fs->ls->dyd->gt.n;
   bl->upval = 0;
+  /* inherit 'insidetbc' from enclosing block */
   bl->insidetbc = (fs->bl != NULL && fs->bl->insidetbc);
-  bl->previous = fs->bl;
+  bl->previous = fs->bl;  /* link block in function's block list */
   fs->bl = bl;
   lua_assert(fs->freereg == luaY_nvarstack(fs));
 }
@@ -677,11 +720,10 @@ static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isloop) {
 ** generates an error for an undefined 'goto'.
 */
 static l_noret undefgoto (LexState *ls, Labeldesc *gt) {
-  const char *msg = "no visible label '%s' for <goto> at line %d";
-  msg = luaO_pushfstring(ls->L, msg, getstr(gt->name), gt->line);
   /* breaks are checked when created, cannot be undefined */
-  lua_assert(!eqstr(gt->name, luaS_newliteral(ls->L, "break")));
-  luaK_semerror(ls, msg);
+  lua_assert(!eqstr(gt->name, ls->brkn));
+  luaK_semerror(ls, "no visible label '%s' for <goto> at line %d",
+                    getstr(gt->name), gt->line);
 }
 
 
@@ -695,7 +737,7 @@ static void leaveblock (FuncState *fs) {
   removevars(fs, bl->nactvar);  /* remove block locals */
   lua_assert(bl->nactvar == fs->nactvar);  /* back to level on entry */
   if (bl->isloop == 2)  /* has to fix pending breaks? */
-    createlabel(ls, luaS_newliteral(ls->L, "break"), 0, 0);
+    createlabel(ls, ls->brkn, 0, 0);
   solvegotos(fs, bl);
   if (bl->previous == NULL) {  /* was it the last block? */
     if (bl->firstgoto < ls->dyd->gt.n)  /* still pending gotos? */
@@ -868,10 +910,8 @@ static void recfield (LexState *ls, ConsControl *cc) {
   FuncState *fs = ls->fs;
   lu_byte reg = ls->fs->freereg;
   expdesc tab, key, val;
-  if (ls->t.token == TK_NAME) {
-    luaY_checklimit(fs, cc->nh, INT_MAX / 2, "items in a constructor");
+  if (ls->t.token == TK_NAME)
     codename(ls, &key);
-  }
   else  /* ls->t.token == '[' */
     yindex(ls, &key);
   cc->nh++;
@@ -1402,6 +1442,15 @@ static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) {
   }
 }
 
+
+/* Create code to store the "top" register in 'var' */
+static void storevartop (FuncState *fs, expdesc *var) {
+  expdesc e;
+  init_exp(&e, VNONRELOC, fs->freereg - 1);
+  luaK_storevar(fs, var, &e);  /* will also free the top register */
+}
+
+
 /*
 ** Parse and compile a multiple assignment. The first "variable"
 ** (a 'suffixedexp') was already read by the caller.
@@ -1435,8 +1484,7 @@ static void restassign (LexState *ls, struct LHS_assign *lh, int nvars) {
       return;  /* avoid default */
     }
   }
-  init_exp(&e, VNONRELOC, ls->fs->freereg-1);  /* default assignment */
-  luaK_storevar(ls->fs, &lh->v, &e);
+  storevartop(ls->fs, &lh->v);  /* default assignment */
 }
 
 
@@ -1469,7 +1517,7 @@ static void breakstat (LexState *ls, int line) {
  ok:
   bl->isloop = 2;  /* signal that block has pending breaks */
   luaX_next(ls);  /* skip break */
-  newgotoentry(ls, luaS_newliteral(ls->L, "break"), line);
+  newgotoentry(ls, ls->brkn, line);
 }
 
 
@@ -1479,11 +1527,9 @@ static void breakstat (LexState *ls, int line) {
 */
 static void checkrepeated (LexState *ls, TString *name) {
   Labeldesc *lb = findlabel(ls, name, ls->fs->firstlabel);
-  if (l_unlikely(lb != NULL)) {  /* already defined? */
-    const char *msg = "label '%s' already defined on line %d";
-    msg = luaO_pushfstring(ls->L, msg, getstr(name), lb->line);
-    luaK_semerror(ls, msg);  /* error */
-  }
+  if (l_unlikely(lb != NULL))  /* already defined? */
+    luaK_semerror(ls, "label '%s' already defined on line %d",
+                      getstr(name), lb->line);  /* error */
 }
 
 
@@ -1605,7 +1651,7 @@ static void fornum (LexState *ls, TString *varname, int line) {
   int base = fs->freereg;
   new_localvarliteral(ls, "(for state)");
   new_localvarliteral(ls, "(for state)");
-  new_localvarkind(ls, varname, RDKCONST);  /* control variable */
+  new_varkind(ls, varname, RDKCONST);  /* control variable */
   checknext(ls, '=');
   exp1(ls);  /* initial value */
   checknext(ls, ',');
@@ -1632,7 +1678,7 @@ static void forlist (LexState *ls, TString *indexname) {
   new_localvarliteral(ls, "(for state)");  /* iterator function */
   new_localvarliteral(ls, "(for state)");  /* state */
   new_localvarliteral(ls, "(for state)");  /* closing var. (after swap) */
-  new_localvarkind(ls, indexname, RDKCONST);  /* control variable */
+  new_varkind(ls, indexname, RDKCONST);  /* control variable */
   /* other declared variables */
   while (testnext(ls, ',')) {
     new_localvar(ls, str_checkname(ls));
@@ -1707,8 +1753,8 @@ static void localfunc (LexState *ls) {
 }
 
 
-static lu_byte getlocalattribute (LexState *ls) {
-  /* ATTRIB -> ['<' Name '>'] */
+static lu_byte getvarattribute (LexState *ls, lu_byte df) {
+  /* attrib -> ['<' NAME '>'] */
   if (testnext(ls, '<')) {
     TString *ts = str_checkname(ls);
     const char *attr = getstr(ts);
@@ -1718,10 +1764,9 @@ static lu_byte getlocalattribute (LexState *ls) {
     else if (strcmp(attr, "close") == 0)
       return RDKTOCLOSE;  /* to-be-closed variable */
     else
-      luaK_semerror(ls,
-        luaO_pushfstring(ls->L, "unknown attribute '%s'", attr));
+      luaK_semerror(ls, "unknown attribute '%s'", attr);
   }
-  return VDKREG;  /* regular variable */
+  return df;  /* return default value */
 }
 
 
@@ -1734,7 +1779,7 @@ static void checktoclose (FuncState *fs, int level) {
 
 
 static void localstat (LexState *ls) {
-  /* stat -> LOCAL NAME ATTRIB { ',' NAME ATTRIB } ['=' explist] */
+  /* stat -> LOCAL NAME attrib { ',' NAME attrib } ['=' explist] */
   FuncState *fs = ls->fs;
   int toclose = -1;  /* index of to-be-closed variable (if any) */
   Vardesc *var;  /* last variable */
@@ -1742,10 +1787,12 @@ static void localstat (LexState *ls) {
   int nvars = 0;
   int nexps;
   expdesc e;
-  do {
-    TString *vname = str_checkname(ls);
-    lu_byte kind = getlocalattribute(ls);
-    vidx = new_localvarkind(ls, vname, kind);
+  /* get prefixed attribute (if any); default is regular local variable */
+  lu_byte defkind = getvarattribute(ls, VDKREG);
+  do {  /* for each variable */
+    TString *vname = str_checkname(ls);  /* get its name */
+    lu_byte kind = getvarattribute(ls, defkind);  /* postfixed attribute */
+    vidx = new_varkind(ls, vname, kind);  /* predeclare it */
     if (kind == RDKTOCLOSE) {  /* to-be-closed? */
       if (toclose != -1)  /* one already present? */
         luaK_semerror(ls, "multiple to-be-closed variables in local list");
@@ -1753,13 +1800,13 @@ static void localstat (LexState *ls) {
     }
     nvars++;
   } while (testnext(ls, ','));
-  if (testnext(ls, '='))
+  if (testnext(ls, '='))  /* initialization? */
     nexps = explist(ls, &e);
   else {
     e.k = VVOID;
     nexps = 0;
   }
-  var = getlocalvardesc(fs, vidx);  /* get last variable */
+  var = getlocalvardesc(fs, vidx);  /* retrieve last variable */
   if (nvars == nexps &&  /* no adjustments? */
       var->vd.kind == RDKCONST &&  /* last variable is const? */
       luaK_exp2const(fs, &e, &var->k)) {  /* compile-time constant? */
@@ -1775,6 +1822,86 @@ static void localstat (LexState *ls) {
 }
 
 
+static lu_byte getglobalattribute (LexState *ls, lu_byte df) {
+  lu_byte kind = getvarattribute(ls, df);
+  switch (kind) {
+    case RDKTOCLOSE:
+      luaK_semerror(ls, "global variables cannot be to-be-closed");
+      break;  /* to avoid warnings */
+    case RDKCONST:
+      return GDKCONST;  /* adjust kind for global variable */
+    default:
+      return kind;
+  }
+}
+
+
+static void globalnames (LexState *ls, lu_byte defkind) {
+  FuncState *fs = ls->fs;
+  int nvars = 0;
+  int lastidx;  /* index of last registered variable */
+  do {  /* for each name */
+    TString *vname = str_checkname(ls);
+    lu_byte kind = getglobalattribute(ls, defkind);
+    lastidx = new_varkind(ls, vname, kind);
+    nvars++;
+  } while (testnext(ls, ','));
+  if (testnext(ls, '=')) {  /* initialization? */
+    expdesc e;
+    int i;
+    int nexps = explist(ls, &e);  /* read list of expressions */
+    adjust_assign(ls, nvars, nexps, &e);
+    for (i = 0; i < nvars; i++) {  /* for each variable */
+      expdesc var;
+      TString *varname = getlocalvardesc(fs, lastidx - i)->vd.name;
+      buildglobal(ls, varname, &var);  /* create global variable in 'var' */
+      storevartop(fs, &var);
+    }
+  }
+  fs->nactvar = cast_short(fs->nactvar + nvars);  /* activate declaration */
+}
+
+
+static void globalstat (LexState *ls) {
+  /* globalstat -> (GLOBAL) attrib '*'
+     globalstat -> (GLOBAL) attrib NAME attrib {',' NAME attrib} */
+  FuncState *fs = ls->fs;
+  /* get prefixed attribute (if any); default is regular global variable */
+  lu_byte defkind = getglobalattribute(ls, GDKREG);
+  if (!testnext(ls, '*'))
+    globalnames(ls, defkind);
+  else {
+    /* use NULL as name to represent '*' entries */
+    new_varkind(ls, NULL, defkind);
+    fs->nactvar++;  /* activate declaration */
+  }
+}
+
+
+static void globalfunc (LexState *ls, int line) {
+  /* globalfunc -> (GLOBAL FUNCTION) NAME body */
+  expdesc var, b;
+  FuncState *fs = ls->fs;
+  TString *fname = str_checkname(ls);
+  new_varkind(ls, fname, GDKREG);  /* declare global variable */
+  fs->nactvar++;  /* enter its scope */
+  buildglobal(ls, fname, &var);
+  body(ls, &b, 0, ls->linenumber);  /* compile and return closure in 'b' */
+  luaK_storevar(fs, &var, &b);
+  luaK_fixline(fs, line);  /* definition "happens" in the first line */
+}
+
+
+static void globalstatfunc (LexState *ls, int line) {
+  /* stat -> GLOBAL globalfunc | GLOBAL globalstat */
+  luaX_next(ls);  /* skip 'global' */
+  if (testnext(ls, TK_FUNCTION))
+    globalfunc(ls, line);
+  else
+    globalstat(ls);
+}
+
+
 static int funcname (LexState *ls, expdesc *v) {
   /* funcname -> NAME {fieldsel} [':' NAME] */
   int ismethod = 0;
@@ -1795,8 +1922,8 @@ static void funcstat (LexState *ls, int line) {
   expdesc v, b;
   luaX_next(ls);  /* skip FUNCTION */
   ismethod = funcname(ls, &v);
-  body(ls, &b, ismethod, line);
   check_readonly(ls, &v);
+  body(ls, &b, ismethod, line);
   luaK_storevar(ls->fs, &v, &b);
   luaK_fixline(ls->fs, line);  /* definition "happens" in the first line */
 }
@@ -1894,6 +2021,10 @@ static void statement (LexState *ls) {
         localstat(ls);
       break;
     }
+    case TK_GLOBAL: {  /* stat -> globalstatfunc */
+      globalstatfunc(ls, line);
+      break;
+    }
     case TK_DBCOLON: {  /* stat -> label */
       luaX_next(ls);  /* skip double colon */
       labelstat(ls, str_checkname(ls), line);
@@ -1913,6 +2044,22 @@ static void statement (LexState *ls) {
       gotostat(ls, line);
       break;
     }
+#if defined(LUA_COMPAT_GLOBAL)
+    case TK_NAME: {
+      /* compatibility code to parse global keyword when "global"
+         is not reserved */
+      if (ls->t.seminfo.ts == ls->glbn) {  /* current = "global"? */
+        int lk = luaX_lookahead(ls);
+        if (lk == '<' || lk == TK_NAME || lk == '*' || lk == TK_FUNCTION) {
+          /* 'global <attrib>' or 'global name' or 'global *' or
+             'global function' */
+          globalstatfunc(ls, line);
+          break;
+        }
+      }  /* else... */
+    }
+#endif
+    /* FALLTHROUGH */
     default: {  /* stat -> func | assignment */
       exprstat(ls);
       break;
diff --git a/lparser.h b/lparser.h
index a3063569..fdbb9b8a 100644
--- a/lparser.h
+++ b/lparser.h
@@ -37,21 +37,27 @@ typedef enum {
                  info = result register */
   VLOCAL,  /* local variable; var.ridx = register index;
               var.vidx = relative index in 'actvar.arr'  */
+  VGLOBAL,  /* global variable;
+               info = relative index in 'actvar.arr' (or -1 for
+                      implicit declaration) */
   VUPVAL,  /* upvalue variable; info = index of upvalue in 'upvalues' */
   VCONST,  /* compile-time <const> variable;
               info = absolute index in 'actvar.arr'  */
   VINDEXED,  /* indexed variable;
                 ind.t = table register;
-                ind.idx = key's R index */
+                ind.idx = key's R index;
+                ind.ro = true if it represents a read-only global;
+                ind.keystr = if key is a string, index in 'k' of that string;
+                             -1 if key is not a string */
   VINDEXUP,  /* indexed upvalue;
-                ind.t = table upvalue;
-                ind.idx = key's K index */
+                ind.idx = key's K index;
+                ind.* as in VINDEXED */
   VINDEXI, /* indexed variable with constant integer;
                 ind.t = table register;
                 ind.idx = key's value */
   VINDEXSTR, /* indexed variable with literal string;
-                ind.t = table register;
-                ind.idx = key's K index */
+                ind.idx = key's K index;
+                ind.* as in VINDEXED */
   VJMP,  /* expression is a test/comparison;
             info = pc of corresponding jump instruction */
   VRELOC,  /* expression can put result in any register;
@@ -75,10 +81,12 @@ typedef struct expdesc {
     struct {  /* for indexed variables */
       short idx;  /* index (R or "long" K) */
       lu_byte t;  /* table (register or upvalue) */
+      lu_byte ro;  /* true if variable is read-only */
+      int keystr;  /* index in 'k' of string key, or -1 if not a string */
     } ind;
     struct {  /* for local variables */
       lu_byte ridx;  /* register holding the variable */
-      unsigned short vidx;  /* compiler index (in 'actvar.arr')  */
+      short vidx;  /* index in 'actvar.arr' */
     } var;
   } u;
   int t;  /* patch list of 'exit when true' */
@@ -87,12 +95,21 @@ typedef struct expdesc {
 
 
 /* kinds of variables */
-#define VDKREG          0   /* regular */
-#define RDKCONST        1   /* constant */
+#define VDKREG          0   /* regular local */
+#define RDKCONST        1   /* local constant */
 #define RDKTOCLOSE      2   /* to-be-closed */
-#define RDKCTC          3   /* compile-time constant */
+#define RDKCTC          3   /* local compile-time constant */
+#define GDKREG          4   /* regular global */
+#define GDKCONST        5   /* global constant */
+
+/* variables that live in registers */
+#define varinreg(v)     ((v)->vd.kind <= RDKTOCLOSE)
+
+/* test for global variables */
+#define varglobal(v)    ((v)->vd.kind >= GDKREG)
+
 
-/* description of an active local variable */
+/* description of an active variable */
 typedef union Vardesc {
   struct {
     TValuefields;  /* constant value (if it is a compile-time constant) */
@@ -111,7 +128,7 @@ typedef struct Labeldesc {
   TString *name;  /* label identifier */
   int pc;  /* position in code */
   int line;  /* line where it appeared */
-  lu_byte nactvar;  /* number of active variables in that position */
+  short nactvar;  /* number of active variables in that position */
   lu_byte close;  /* true for goto that escapes upvalues */
 } Labeldesc;
 
@@ -156,7 +173,7 @@ typedef struct FuncState {
   int firstlocal;  /* index of first local var (in Dyndata array) */
   int firstlabel;  /* index of first label (in 'dyd->label->arr') */
   short ndebugvars;  /* number of elements in 'f->locvars' */
-  lu_byte nactvar;  /* number of active local variables */
+  short nactvar;  /* number of active variable declarations */
   lu_byte nups;  /* number of upvalues */
   lu_byte freereg;  /* first free register */
   lu_byte iwthabs;  /* instructions issued since last absolute line info */
diff --git a/lstate.c b/lstate.c
index 20ed838f..70a11aae 100644
--- a/lstate.c
+++ b/lstate.c
@@ -326,6 +326,8 @@ LUA_API int lua_closethread (lua_State *L, lua_State *from) {
   lua_lock(L);
   L->nCcalls = (from) ? getCcalls(from) : 0;
   status = luaE_resetthread(L, L->status);
+  if (L == from)  /* closing itself? */
+    luaD_throwbaselevel(L, status);
   lua_unlock(L);
   return APIstatus(status);
 }
diff --git a/lstate.h b/lstate.h
index f841c232..80df3b0a 100644
--- a/lstate.h
+++ b/lstate.h
@@ -85,7 +85,7 @@ typedef struct CallInfo CallInfo;
 ** they must be visited again at the end of the cycle), but they are
 ** marked black because assignments to them must activate barriers (to
 ** move them back to TOUCHED1).
-** - Open upvales are kept gray to avoid barriers, but they stay out
+** - Open upvalues are kept gray to avoid barriers, but they stay out
 ** of gray lists. (They don't even have a 'gclist' field.)
 */
 
@@ -232,7 +232,7 @@ struct CallInfo {
 /* call is running a C function (still in first 16 bits) */
 #define CIST_C          (1u << (CIST_RECST + 3))
 /* call is on a fresh "luaV_execute" frame */
-#define CIST_FRESH      cast(l_uint32, CIST_C << 1)
+#define CIST_FRESH      (cast(l_uint32, CIST_C) << 1)
 /* function is closing tbc variables */
 #define CIST_CLSRET     (CIST_FRESH << 1)
 /* function has tbc variables to close */
diff --git a/lstring.c b/lstring.c
index b5c8f89f..17c6fd8f 100644
--- a/lstring.c
+++ b/lstring.c
@@ -39,14 +39,14 @@
 
 
 /*
-** equality for long strings
+** generic equality for strings
 */
-int luaS_eqlngstr (TString *a, TString *b) {
-  size_t len = a->u.lnglen;
-  lua_assert(a->tt == LUA_VLNGSTR && b->tt == LUA_VLNGSTR);
-  return (a == b) ||  /* same instance or... */
-    ((len == b->u.lnglen) &&  /* equal length and ... */
-     (memcmp(getlngstr(a), getlngstr(b), len) == 0));  /* equal contents */
+int luaS_eqstr (TString *a, TString *b) {
+  size_t len1, len2;
+  const char *s1 = getlstr(a, len1);
+  const char *s2 = getlstr(b, len2);
+  return ((len1 == len2) &&  /* equal length and ... */
+          (memcmp(s1, s2, len1) == 0));  /* equal contents */
 }
 
 
@@ -315,28 +315,9 @@ static void f_newext (lua_State *L, void *ud) {
 }
 
 
-static void f_pintern (lua_State *L, void *ud) {
-  struct NewExt *ne = cast(struct NewExt *, ud);
-  ne->ts = internshrstr(L, ne->s, ne->len);
-}
-
-
 TString *luaS_newextlstr (lua_State *L,
                   const char *s, size_t len, lua_Alloc falloc, void *ud) {
   struct NewExt ne;
-  if (len <= LUAI_MAXSHORTLEN) {  /* short string? */
-    ne.s = s; ne.len = len;
-    if (!falloc)
-      f_pintern(L, &ne);  /* just internalize string */
-    else {
-      TStatus status = luaD_rawrunprotected(L, f_pintern, &ne);
-      (*falloc)(ud, cast_voidp(s), len + 1, 0);  /* free external string */
-      if (status != LUA_OK)  /* memory error? */
-        luaM_error(L);  /* re-raise memory error */
-    }
-    return ne.ts;
-  }
-  /* "normal" case: long strings */
   if (!falloc) {
     ne.kind = LSTRFIX;
     f_newext(L, &ne);  /* just create header */
@@ -357,3 +338,16 @@ TString *luaS_newextlstr (lua_State *L,
 }
 
 
+/*
+** Normalize an external string: If it is short, internalize it.
+*/
+TString *luaS_normstr (lua_State *L, TString *ts) {
+  size_t len = ts->u.lnglen;
+  if (len > LUAI_MAXSHORTLEN)
+    return ts;  /* long string; keep the original */
+  else {
+    const char *str = getlngstr(ts);
+    return internshrstr(L, str, len);
+  }
+}
+
diff --git a/lstring.h b/lstring.h
index 1751e043..2eac222b 100644
--- a/lstring.h
+++ b/lstring.h
@@ -56,7 +56,7 @@
 
 LUAI_FUNC unsigned luaS_hash (const char *str, size_t l, unsigned seed);
 LUAI_FUNC unsigned luaS_hashlongstr (TString *ts);
-LUAI_FUNC int luaS_eqlngstr (TString *a, TString *b);
+LUAI_FUNC int luaS_eqstr (TString *a, TString *b);
 LUAI_FUNC void luaS_resize (lua_State *L, int newsize);
 LUAI_FUNC void luaS_clearcache (global_State *g);
 LUAI_FUNC void luaS_init (lua_State *L);
@@ -69,5 +69,6 @@ LUAI_FUNC TString *luaS_createlngstrobj (lua_State *L, size_t l);
 LUAI_FUNC TString *luaS_newextlstr (lua_State *L,
                 const char *s, size_t len, lua_Alloc falloc, void *ud);
 LUAI_FUNC size_t luaS_sizelngstr (size_t len, int kind);
+LUAI_FUNC TString *luaS_normstr (lua_State *L, TString *ts);
 
 #endif
diff --git a/lstrlib.c b/lstrlib.c
index 321d6a0b..d9735903 100644
--- a/lstrlib.c
+++ b/lstrlib.c
@@ -132,27 +132,31 @@ static int str_upper (lua_State *L) {
 }
 
 
+/*
+** MAX_SIZE is limited both by size_t and lua_Integer.
+** When x <= MAX_SIZE, x can be safely cast to size_t or lua_Integer.
+*/
 static int str_rep (lua_State *L) {
-  size_t l, lsep;
-  const char *s = luaL_checklstring(L, 1, &l);
+  size_t len, lsep;
+  const char *s = luaL_checklstring(L, 1, &len);
   lua_Integer n = luaL_checkinteger(L, 2);
   const char *sep = luaL_optlstring(L, 3, "", &lsep);
   if (n <= 0)
     lua_pushliteral(L, "");
-  else if (l_unlikely(l + lsep < l || l + lsep > MAX_SIZE / cast_sizet(n)))
+  else if (l_unlikely(len > MAX_SIZE - lsep ||
+               cast_st2S(len + lsep) > cast_st2S(MAX_SIZE) / n))
     return luaL_error(L, "resulting string too large");
   else {
-    size_t totallen = ((size_t)n * (l + lsep)) - lsep;
+    size_t totallen = (cast_sizet(n) * (len + lsep)) - lsep;
     luaL_Buffer b;
     char *p = luaL_buffinitsize(L, &b, totallen);
     while (n-- > 1) {  /* first n-1 copies (followed by separator) */
-      memcpy(p, s, l * sizeof(char)); p += l;
+      memcpy(p, s, len * sizeof(char)); p += len;
       if (lsep > 0) {  /* empty 'memcpy' is not that cheap */
-        memcpy(p, sep, lsep * sizeof(char));
-        p += lsep;
+        memcpy(p, sep, lsep * sizeof(char)); p += lsep;
       }
     }
-    memcpy(p, s, l * sizeof(char));  /* last copy (not followed by separator) */
+    memcpy(p, s, len * sizeof(char));  /* last copy without separator */
     luaL_pushresultsize(&b, totallen);
   }
   return 1;
@@ -1544,8 +1548,10 @@ static KOption getdetails (Header *h, size_t totalsize, const char **fmt,
   else {
     if (align > h->maxalign)  /* enforce maximum alignment */
       align = h->maxalign;
-    if (l_unlikely(!ispow2(align)))  /* not a power of 2? */
+    if (l_unlikely(!ispow2(align))) {  /* not a power of 2? */
+      *ntoalign = 0;  /* to avoid warnings */
       luaL_argerror(h->L, 1, "format asks for alignment not power of 2");
+    }
     else {
       /* 'szmoda' = totalsize % align */
       unsigned szmoda = cast_uint(totalsize & (align - 1));
@@ -1809,8 +1815,8 @@ static int str_unpack (lua_State *L) {
         lua_Unsigned len = (lua_Unsigned)unpackint(L, data + pos,
                                           h.islittle, cast_int(size), 0);
         luaL_argcheck(L, len <= ld - pos - size, 2, "data string too short");
-        lua_pushlstring(L, data + pos + size, len);
-        pos += len;  /* skip string */
+        lua_pushlstring(L, data + pos + size, cast_sizet(len));
+        pos += cast_sizet(len);  /* skip string */
         break;
       }
       case Kzstr: {
diff --git a/ltable.c b/ltable.c
index 0b3ec176..4017d8c7 100644
--- a/ltable.c
+++ b/ltable.c
@@ -234,41 +234,51 @@ l_sinline Node *mainpositionfromnode (const Table *t, Node *nd) {
 ** Check whether key 'k1' is equal to the key in node 'n2'. This
 ** equality is raw, so there are no metamethods. Floats with integer
 ** values have been normalized, so integers cannot be equal to
-** floats. It is assumed that 'eqshrstr' is simply pointer equality, so
-** that short strings are handled in the default case.
-** A true 'deadok' means to accept dead keys as equal to their original
-** values. All dead keys are compared in the default case, by pointer
-** identity. (Only collectable objects can produce dead keys.) Note that
-** dead long strings are also compared by identity.
-** Once a key is dead, its corresponding value may be collected, and
-** then another value can be created with the same address. If this
-** other value is given to 'next', 'equalkey' will signal a false
-** positive. In a regular traversal, this situation should never happen,
-** as all keys given to 'next' came from the table itself, and therefore
-** could not have been collected. Outside a regular traversal, we
-** have garbage in, garbage out. What is relevant is that this false
-** positive does not break anything.  (In particular, 'next' will return
-** some other valid item on the table or nil.)
+** floats. It is assumed that 'eqshrstr' is simply pointer equality,
+** so that short strings are handled in the default case.  The flag
+** 'deadok' means to accept dead keys as equal to their original values.
+** (Only collectable objects can produce dead keys.) Note that dead
+** long strings are also compared by identity.  Once a key is dead,
+** its corresponding value may be collected, and then another value
+** can be created with the same address. If this other value is given
+** to 'next', 'equalkey' will signal a false positive. In a regular
+** traversal, this situation should never happen, as all keys given to
+** 'next' came from the table itself, and therefore could not have been
+** collected. Outside a regular traversal, we have garbage in, garbage
+** out. What is relevant is that this false positive does not break
+** anything.  (In particular, 'next' will return some other valid item
+** on the table or nil.)
 */
 static int equalkey (const TValue *k1, const Node *n2, int deadok) {
-  if ((rawtt(k1) != keytt(n2)) &&  /* not the same variants? */
-       !(deadok && keyisdead(n2) && iscollectable(k1)))
-   return 0;  /* cannot be same key */
-  switch (keytt(n2)) {
-    case LUA_VNIL: case LUA_VFALSE: case LUA_VTRUE:
-      return 1;
-    case LUA_VNUMINT:
-      return (ivalue(k1) == keyival(n2));
-    case LUA_VNUMFLT:
-      return luai_numeq(fltvalue(k1), fltvalueraw(keyval(n2)));
-    case LUA_VLIGHTUSERDATA:
-      return pvalue(k1) == pvalueraw(keyval(n2));
-    case LUA_VLCF:
-      return fvalue(k1) == fvalueraw(keyval(n2));
-    case ctb(LUA_VLNGSTR):
-      return luaS_eqlngstr(tsvalue(k1), keystrval(n2));
-    default:
+  if (rawtt(k1) != keytt(n2)) {  /* not the same variants? */
+    if (keyisshrstr(n2) && ttislngstring(k1)) {
+      /* an external string can be equal to a short-string key */
+      return luaS_eqstr(tsvalue(k1), keystrval(n2));
+    }
+    else if (deadok && keyisdead(n2) && iscollectable(k1)) {
+      /* a collectable value can be equal to a dead key */
       return gcvalue(k1) == gcvalueraw(keyval(n2));
+   }
+   else
+     return 0;  /* otherwise, different variants cannot be equal */
+  }
+  else {  /* equal variants */
+    switch (keytt(n2)) {
+      case LUA_VNIL: case LUA_VFALSE: case LUA_VTRUE:
+        return 1;
+      case LUA_VNUMINT:
+        return (ivalue(k1) == keyival(n2));
+      case LUA_VNUMFLT:
+        return luai_numeq(fltvalue(k1), fltvalueraw(keyval(n2)));
+      case LUA_VLIGHTUSERDATA:
+        return pvalue(k1) == pvalueraw(keyval(n2));
+      case LUA_VLCF:
+        return fvalue(k1) == fvalueraw(keyval(n2));
+      case ctb(LUA_VLNGSTR):
+        return luaS_eqstr(tsvalue(k1), keystrval(n2));
+      default:
+        return gcvalue(k1) == gcvalueraw(keyval(n2));
+    }
   }
 }
 
@@ -1158,6 +1168,14 @@ void luaH_finishset (lua_State *L, Table *t, const TValue *key,
       else if (l_unlikely(luai_numisnan(f)))
         luaG_runerror(L, "table index is NaN");
     }
+    else if (isextstr(key)) {  /* external string? */
+      /* If string is short, must internalize it to be used as table key */
+      TString *ts = luaS_normstr(L, tsvalue(key));
+      setsvalue2s(L, L->top.p++, ts);  /* anchor 'ts' (EXTRA_STACK) */
+      luaH_newkey(L, t, s2v(L->top.p - 1), value);
+      L->top.p--;
+      return;
+    }
     luaH_newkey(L, t, key, value);
   }
   else if (hres > 0) {  /* regular Node? */
@@ -1202,24 +1220,36 @@ void luaH_setint (lua_State *L, Table *t, lua_Integer key, TValue *value) {
 
 /*
 ** Try to find a boundary in the hash part of table 't'. From the
-** caller, we know that 'j' is zero or present and that 'j + 1' is
-** present. We want to find a larger key that is absent from the
-** table, so that we can do a binary search between the two keys to
-** find a boundary. We keep doubling 'j' until we get an absent index.
-** If the doubling would overflow, we try LUA_MAXINTEGER. If it is
-** absent, we are ready for the binary search. ('j', being max integer,
-** is larger or equal to 'i', but it cannot be equal because it is
-** absent while 'i' is present; so 'j > i'.) Otherwise, 'j' is a
-** boundary. ('j + 1' cannot be a present integer key because it is
-** not a valid integer in Lua.)
+** caller, we know that 'asize + 1' is present. We want to find a larger
+** key that is absent from the table, so that we can do a binary search
+** between the two keys to find a boundary. We keep doubling 'j' until
+** we get an absent index.  If the doubling would overflow, we try
+** LUA_MAXINTEGER. If it is absent, we are ready for the binary search.
+** ('j', being max integer, is larger or equal to 'i', but it cannot be
+** equal because it is absent while 'i' is present.) Otherwise, 'j' is a
+** boundary. ('j + 1' cannot be a present integer key because it is not
+** a valid integer in Lua.)
+** About 'rnd': If we used a fixed algorithm, a bad actor could fill
+** a table with only the keys that would be probed, in such a way that
+** a small table could result in a huge length. To avoid that, we use
+** the state's seed as a source of randomness. For the first probe,
+** we "randomly double" 'i' by adding to it a random number roughly its
+** width.
 */
-static lua_Unsigned hash_search (Table *t, lua_Unsigned j) {
-  lua_Unsigned i;
-  if (j == 0) j++;  /* the caller ensures 'j + 1' is present */
-  do {
+static lua_Unsigned hash_search (lua_State *L, Table *t, unsigned asize) {
+  lua_Unsigned i = asize + 1;  /* caller ensures t[i] is present */
+  unsigned rnd = G(L)->seed;
+  int n = (asize > 0) ? luaO_ceillog2(asize) : 0;  /* width of 'asize' */
+  unsigned mask = (1u << n) - 1;  /* 11...111 with the width of 'asize' */
+  unsigned incr = (rnd & mask) + 1;  /* first increment (at least 1) */
+  lua_Unsigned j = (incr <= l_castS2U(LUA_MAXINTEGER) - i) ? i + incr : i + 1;
+  rnd >>= n;  /* used 'n' bits from 'rnd' */
+  while (!hashkeyisempty(t, j)) {  /* repeat until an absent t[j] */
     i = j;  /* 'i' is a present index */
-    if (j <= l_castS2U(LUA_MAXINTEGER) / 2)
-      j *= 2;
+    if (j <= l_castS2U(LUA_MAXINTEGER)/2 - 1) {
+      j = j*2 + (rnd & 1);  /* try again with 2j or 2j+1 */
+      rnd >>= 1;
+    }
     else {
       j = LUA_MAXINTEGER;
       if (hashkeyisempty(t, j))  /* t[j] not present? */
@@ -1227,7 +1257,7 @@ static lua_Unsigned hash_search (Table *t, lua_Unsigned j) {
       else  /* weird case */
         return j;  /* well, max integer is a boundary... */
     }
-  } while (!hashkeyisempty(t, j));  /* repeat until an absent t[j] */
+  }
   /* i < j  &&  t[i] present  &&  t[j] absent */
   while (j - i > 1u) {  /* do a binary search between them */
     lua_Unsigned m = (i + j) / 2;
@@ -1268,7 +1298,7 @@ static lua_Unsigned newhint (Table *t, unsigned hint) {
 ** If there is no array part, or its last element is non empty, the
 ** border may be in the hash part.
 */
-lua_Unsigned luaH_getn (Table *t) {
+lua_Unsigned luaH_getn (lua_State *L, Table *t) {
   unsigned asize = t->asize;
   if (asize > 0) {  /* is there an array part? */
     const unsigned maxvicinity = 4;
@@ -1309,7 +1339,7 @@ lua_Unsigned luaH_getn (Table *t) {
   if (isdummy(t) || hashkeyisempty(t, asize + 1))
     return asize;  /* 'asize + 1' is empty */
   else  /* 'asize + 1' is also non empty */
-    return hash_search(t, asize);
+    return hash_search(L, t, asize);
 }
 
 
diff --git a/ltable.h b/ltable.h
index ca21e692..f3b7bc7e 100644
--- a/ltable.h
+++ b/ltable.h
@@ -173,7 +173,7 @@ LUAI_FUNC void luaH_resizearray (lua_State *L, Table *t, unsigned nasize);
 LUAI_FUNC lu_mem luaH_size (Table *t);
 LUAI_FUNC void luaH_free (lua_State *L, Table *t);
 LUAI_FUNC int luaH_next (lua_State *L, Table *t, StkId key);
-LUAI_FUNC lua_Unsigned luaH_getn (Table *t);
+LUAI_FUNC lua_Unsigned luaH_getn (lua_State *L, Table *t);
 
 
 #if defined(LUA_DEBUG)
diff --git a/ltests.c b/ltests.c
index 1517aa88..d92cd6c5 100644
--- a/ltests.c
+++ b/ltests.c
@@ -910,9 +910,9 @@ static int get_limits (lua_State *L) {
 
 static int mem_query (lua_State *L) {
   if (lua_isnone(L, 1)) {
-    lua_pushinteger(L, cast(lua_Integer, l_memcontrol.total));
-    lua_pushinteger(L, cast(lua_Integer, l_memcontrol.numblocks));
-    lua_pushinteger(L, cast(lua_Integer, l_memcontrol.maxmem));
+    lua_pushinteger(L, cast_Integer(l_memcontrol.total));
+    lua_pushinteger(L, cast_Integer(l_memcontrol.numblocks));
+    lua_pushinteger(L, cast_Integer(l_memcontrol.maxmem));
     return 3;
   }
   else if (lua_isnumber(L, 1)) {
@@ -926,7 +926,7 @@ static int mem_query (lua_State *L) {
     int i;
     for (i = LUA_NUMTYPES - 1; i >= 0; i--) {
       if (strcmp(t, ttypename(i)) == 0) {
-        lua_pushinteger(L, cast(lua_Integer, l_memcontrol.objcount[i]));
+        lua_pushinteger(L, cast_Integer(l_memcontrol.objcount[i]));
         return 1;
       }
     }
@@ -1066,15 +1066,19 @@ static int tracegc (lua_State *L) {
 
 static int hash_query (lua_State *L) {
   if (lua_isnone(L, 2)) {
+    TString *ts;
     luaL_argcheck(L, lua_type(L, 1) == LUA_TSTRING, 1, "string expected");
-    lua_pushinteger(L, cast_int(tsvalue(obj_at(L, 1))->hash));
+    ts = tsvalue(obj_at(L, 1));
+    if (ts->tt == LUA_VLNGSTR)
+      luaS_hashlongstr(ts);  /* make sure long string has a hash */
+    lua_pushinteger(L, cast_int(ts->hash));
   }
   else {
     TValue *o = obj_at(L, 1);
     Table *t;
     luaL_checktype(L, 2, LUA_TTABLE);
     t = hvalue(obj_at(L, 2));
-    lua_pushinteger(L, cast(lua_Integer, luaH_mainposition(t, o) - t->node));
+    lua_pushinteger(L, cast_Integer(luaH_mainposition(t, o) - t->node));
   }
   return 1;
 }
@@ -1082,9 +1086,9 @@ static int hash_query (lua_State *L) {
 
 static int stacklevel (lua_State *L) {
   int a = 0;
-  lua_pushinteger(L, cast(lua_Integer, L->top.p - L->stack.p));
+  lua_pushinteger(L, cast_Integer(L->top.p - L->stack.p));
   lua_pushinteger(L, stacksize(L));
-  lua_pushinteger(L, cast(lua_Integer, L->nCcalls));
+  lua_pushinteger(L, cast_Integer(L->nCcalls));
   lua_pushinteger(L, L->nci);
   lua_pushinteger(L, (lua_Integer)(size_t)&a);
   return 5;
@@ -1099,9 +1103,9 @@ static int table_query (lua_State *L) {
   t = hvalue(obj_at(L, 1));
   asize = t->asize;
   if (i == -1) {
-    lua_pushinteger(L, cast(lua_Integer, asize));
-    lua_pushinteger(L, cast(lua_Integer, allocsizenode(t)));
-    lua_pushinteger(L, cast(lua_Integer, asize > 0 ? *lenhint(t) : 0));
+    lua_pushinteger(L, cast_Integer(asize));
+    lua_pushinteger(L, cast_Integer(allocsizenode(t)));
+    lua_pushinteger(L, cast_Integer(asize > 0 ? *lenhint(t) : 0));
     return 3;
   }
   else if (cast_uint(i) < asize) {
@@ -1157,7 +1161,7 @@ static int test_codeparam (lua_State *L) {
 static int test_applyparam (lua_State *L) {
   lua_Integer p = luaL_checkinteger(L, 1);
   lua_Integer x = luaL_checkinteger(L, 2);
-  lua_pushinteger(L, cast(lua_Integer, luaO_applyparam(cast_byte(p), x)));
+  lua_pushinteger(L, cast_Integer(luaO_applyparam(cast_byte(p), x)));
   return 1;
 }
 
@@ -1257,7 +1261,7 @@ static int pushuserdata (lua_State *L) {
 
 
 static int udataval (lua_State *L) {
-  lua_pushinteger(L, cast(lua_Integer, cast(size_t, lua_touserdata(L, 1))));
+  lua_pushinteger(L, cast_st2S(cast_sizet(lua_touserdata(L, 1))));
   return 1;
 }
 
@@ -1294,7 +1298,7 @@ static int num2int (lua_State *L) {
 
 
 static int makeseed (lua_State *L) {
-  lua_pushinteger(L, cast(lua_Integer, luaL_makeseed(L)));
+  lua_pushinteger(L, cast_Integer(luaL_makeseed(L)));
   return 1;
 }
 
@@ -1638,7 +1642,7 @@ static int runC (lua_State *L, lua_State *L1, const char *pc) {
     }
     else if EQ("func2num") {
       lua_CFunction func = lua_tocfunction(L1, getindex);
-      lua_pushinteger(L1, cast(lua_Integer, cast(size_t, func)));
+      lua_pushinteger(L1, cast_st2S(cast_sizet(func)));
     }
     else if EQ("getfield") {
       int t = getindex;
@@ -2011,7 +2015,7 @@ static int Cfunc (lua_State *L) {
 static int Cfunck (lua_State *L, int status, lua_KContext ctx) {
   lua_pushstring(L, statcodes[status]);
   lua_setglobal(L, "status");
-  lua_pushinteger(L, cast(lua_Integer, ctx));
+  lua_pushinteger(L, cast_Integer(ctx));
   lua_setglobal(L, "ctx");
   return runC(L, L, lua_tostring(L, cast_int(ctx)));
 }
diff --git a/ltests.h b/ltests.h
index 7f0ce404..d34e9d42 100644
--- a/ltests.h
+++ b/ltests.h
@@ -14,6 +14,7 @@
 /* test Lua with compatibility code */
 #define LUA_COMPAT_MATHLIB
 #define LUA_COMPAT_LT_LE
+#undef LUA_COMPAT_GLOBAL
 
 
 #define LUA_DEBUG
@@ -154,7 +155,6 @@ LUA_API void *debug_realloc (void *ud, void *block,
 ** Reduce maximum stack size to make stack-overflow tests run faster.
 ** (But value is still large enough to overflow smaller integers.)
 */
-#undef LUAI_MAXSTACK
 #define LUAI_MAXSTACK   68000
 
 
diff --git a/lua.c b/lua.c
index b611cbca..b2967a44 100644
--- a/lua.c
+++ b/lua.c
@@ -303,7 +303,8 @@ static int collectargs (char **argv, int *first) {
       case '-':  /* '--' */
         if (argv[i][2] != '\0')  /* extra characters after '--'? */
           return has_error;  /* invalid option */
-        *first = i + 1;
+        /* if there is a script name, it comes after '--' */
+        *first = (argv[i + 1] != NULL) ? i + 1 : 0;
         return args;
       case '\0':  /* '-' */
         return args;  /* script "name" is '-' */
@@ -432,32 +433,41 @@ static int handle_luainit (lua_State *L) {
 
 
 /*
-** lua_readline defines how to show a prompt and then read a line from
-** the standard input.
-** lua_saveline defines how to "save" a read line in a "history".
-** lua_freeline defines how to free a line read by lua_readline.
+** * lua_initreadline initializes the readline system.
+** * lua_readline defines how to show a prompt and then read a line from
+**   the standard input.
+** * lua_saveline defines how to "save" a read line in a "history".
+** * lua_freeline defines how to free a line read by lua_readline.
 */
 
-#if defined(LUA_USE_READLINE)
+#if !defined(lua_readline)      /* { */
+/* Otherwise, all previously listed functions should be defined. */
+
+#if defined(LUA_USE_READLINE)   /* { */
+/* Lua will be linked with '-lreadline' */
 
 #include <readline/readline.h>
 #include <readline/history.h>
+
 #define lua_initreadline(L)     ((void)L, rl_readline_name="lua")
-#define lua_readline(b,p)       ((void)b, readline(p))
+#define lua_readline(buff,prompt)       ((void)buff, readline(prompt))
 #define lua_saveline(line)      add_history(line)
-#define lua_freeline(b)         free(b)
+#define lua_freeline(line)      free(line)
 
-#endif
+#else           /* }{ */
+/* use dynamically loaded readline (or nothing) */
 
+/* pointer to 'readline' function (if any) */
+typedef char *(*l_readlineT) (const char *prompt);
+static l_readlineT l_readline = NULL;
 
-#if !defined(lua_readline)      /* { */
+/* pointer to 'add_history' function (if any) */
+typedef void (*l_addhistT) (const char *string);
+static l_addhistT l_addhist = NULL;
 
-/* pointer to dynamically loaded 'readline' function (if any) */
-typedef char *(*l_readline_t) (const char *prompt);
-static l_readline_t l_readline = NULL;
 
 static char *lua_readline (char *buff, const char *prompt) {
-  if (l_readline != NULL)  /* is there a dynamic 'readline'? */
+  if (l_readline != NULL)  /* is there a 'readline'? */
     return (*l_readline)(prompt);  /* use it */
   else {  /* emulate 'readline' over 'buff' */
     fputs(prompt, stdout);
@@ -467,33 +477,25 @@ static char *lua_readline (char *buff, const char *prompt) {
 }
 
 
-/* pointer to dynamically loaded 'add_history' function (if any) */
-typedef void (*l_addhist_t) (const char *string);
-static l_addhist_t l_addhist = NULL;
-
 static void lua_saveline (const char *line) {
-  if (l_addhist != NULL)  /* is there a dynamic 'add_history'? */
+  if (l_addhist != NULL)  /* is there an 'add_history'? */
     (*l_addhist)(line);  /* use it */
   /* else nothing to be done */
 }
 
 
 static void lua_freeline (char *line) {
-  if (l_readline != NULL)  /* is there a dynamic 'readline'? */
+  if (l_readline != NULL)  /* is there a 'readline'? */
     free(line);  /* free line created by it */
   /* else 'lua_readline' used an automatic buffer; nothing to free */
 }
 
 
-#if !defined(LUA_USE_DLOPEN) || !defined(LUA_READLINELIB)
-
-#define lua_initreadline(L)  ((void)L)
-
-#else /* { */
+#if defined(LUA_USE_DLOPEN) && defined(LUA_READLINELIB)         /* { */
+/* try to load 'readline' dynamically */
 
 #include <dlfcn.h>
 
-
 static void lua_initreadline (lua_State *L) {
   void *lib = dlopen(LUA_READLINELIB, RTLD_NOW | RTLD_LOCAL);
   if (lib == NULL)
@@ -501,16 +503,23 @@ static void lua_initreadline (lua_State *L) {
   else {
     const char **name = cast(const char**, dlsym(lib, "rl_readline_name"));
     if (name != NULL)
-      *name = "Lua";
-    l_readline = cast(l_readline_t, cast_func(dlsym(lib, "readline")));
+      *name = "lua";
+    l_readline = cast(l_readlineT, cast_func(dlsym(lib, "readline")));
+    l_addhist = cast(l_addhistT, cast_func(dlsym(lib, "add_history")));
     if (l_readline == NULL)
       lua_warning(L, "unable to load 'readline'", 0);
-    else
-      l_addhist = cast(l_addhist_t, cast_func(dlsym(lib, "add_history")));
   }
 }
 
-#endif  /* } */
+#else           /* }{ */
+/* no dlopen or LUA_READLINELIB undefined */
+
+/* Leave pointers with NULL */
+#define lua_initreadline(L)     ((void)L)
+
+#endif          /* } */
+
+#endif                          /* } */
 
 #endif                          /* } */
 
diff --git a/lua.h b/lua.h
index 95e0db32..131a8fcb 100644
--- a/lua.h
+++ b/lua.h
@@ -37,10 +37,10 @@
 
 /*
 ** Pseudo-indices
-** (-LUAI_MAXSTACK is the minimum valid index; we keep some free empty
-** space after that to help overflow detection)
+** (The stack size is limited to INT_MAX/2; we keep some free empty
+** space after that to help overflow detection.)
 */
-#define LUA_REGISTRYINDEX       (-LUAI_MAXSTACK - 1000)
+#define LUA_REGISTRYINDEX       (-(INT_MAX/2 + 1000))
 #define lua_upvalueindex(i)     (LUA_REGISTRYINDEX - (i))
 
 
diff --git a/luaconf.h b/luaconf.h
index bd394650..0adc9c13 100644
--- a/luaconf.h
+++ b/luaconf.h
@@ -59,7 +59,7 @@
 
 
 /*
-** When Posix DLL ('LUA_USE_DLOPEN') is enabled, the Lua stand-alone
+** When POSIX DLL ('LUA_USE_DLOPEN') is enabled, the Lua stand-alone
 ** application will try to dynamically link a 'readline' facility
 ** for its REPL.  In that case, LUA_READLINELIB is the name of the
 ** library it will look for those facilities.  If lua.c cannot open
@@ -76,7 +76,7 @@
 
 #if defined(LUA_USE_MACOSX)
 #define LUA_USE_POSIX
-#define LUA_USE_DLOPEN          /* MacOS does not need -ldl */
+#define LUA_USE_DLOPEN          /* macOS does not need -ldl */
 #define LUA_READLINELIB         "libedit.dylib"
 #endif
 
@@ -88,7 +88,7 @@
 
 
 #if defined(LUA_USE_C89) && defined(LUA_USE_POSIX)
-#error "Posix is not compatible with C89"
+#error "POSIX is not compatible with C89"
 #endif
 
 
@@ -356,6 +356,12 @@
 */
 
 /*
+@@ LUA_COMPAT_GLOBAL avoids 'global' being a reserved word
+*/
+#define LUA_COMPAT_GLOBAL
+
+
+/*
 @@ LUA_COMPAT_5_3 controls other macros for compatibility with Lua 5.3.
 ** You can define it to get all options, or change specific options
 ** to fit your specific needs.
@@ -758,20 +764,6 @@
 */
 
 /*
-@@ LUAI_MAXSTACK limits the size of the Lua stack.
-** CHANGE it if you need a different limit. This limit is arbitrary;
-** its only purpose is to stop Lua from consuming unlimited stack
-** space and to reserve some numbers for pseudo-indices.
-** (It must fit into max(int)/2.)
-*/
-#if 1000000 < (INT_MAX / 2)
-#define LUAI_MAXSTACK           1000000
-#else
-#define LUAI_MAXSTACK           (INT_MAX / 2u)
-#endif
-
-
-/*
 @@ LUA_EXTRASPACE defines the size of a raw memory area associated with
 ** a Lua state with very fast access.
 ** CHANGE it if you need a different size.
diff --git a/lundump.c b/lundump.c
index d53bfc9a..76f0ddc1 100644
--- a/lundump.c
+++ b/lundump.c
@@ -37,7 +37,7 @@ typedef struct {
   const char *name;
   Table *h;  /* list for string reuse */
   size_t offset;  /* current position relative to beginning of dump */
-  lua_Integer nstr;  /* number of strings in the list */
+  lua_Unsigned nstr;  /* number of strings in the list */
   lu_byte fixed;  /* dump is fixed in memory */
 } LoadState;
 
@@ -94,8 +94,8 @@ static lu_byte loadByte (LoadState *S) {
 }
 
 
-static size_t loadVarint (LoadState *S, size_t limit) {
-  size_t x = 0;
+static lua_Unsigned loadVarint (LoadState *S, lua_Unsigned limit) {
+  lua_Unsigned x = 0;
   int b;
   limit >>= 7;
   do {
@@ -109,7 +109,7 @@ static size_t loadVarint (LoadState *S, size_t limit) {
 
 
 static size_t loadSize (LoadState *S) {
-  return loadVarint(S, MAX_SIZE);
+  return cast_sizet(loadVarint(S, MAX_SIZE));
 }
 
 
@@ -127,9 +127,12 @@ static lua_Number loadNumber (LoadState *S) {
 
 
 static lua_Integer loadInteger (LoadState *S) {
-  lua_Integer x;
-  loadVar(S, x);
-  return x;
+  lua_Unsigned cx = loadVarint(S, LUA_MAXUNSIGNED);
+  /* decode unsigned to signed */
+  if ((cx & 1) != 0)
+    return l_castU2S(~(cx >> 1));
+  else
+    return l_castU2S(cx >> 1);
 }
 
 
@@ -149,10 +152,11 @@ static void loadString (LoadState *S, Proto *p, TString **sl) {
     return;
   }
   else if (size == 1) {  /* previously saved string? */
-    lua_Integer idx = cast(lua_Integer, loadSize(S));  /* get its index */
+    lua_Unsigned idx = loadVarint(S, LUA_MAXUNSIGNED);  /* get its index */
     TValue stv;
-    luaH_getint(S->h, idx, &stv);  /* get its value */
-    *sl = ts = tsvalue(&stv);
+    if (novariant(luaH_getint(S->h, l_castU2S(idx), &stv)) != LUA_TSTRING)
+      error(S, "invalid string index");
+    *sl = ts = tsvalue(&stv);  /* get its value */
     luaC_objbarrier(L, p, ts);
     return;  /* do not save it again */
   }
@@ -175,7 +179,7 @@ static void loadString (LoadState *S, Proto *p, TString **sl) {
   /* add string to list of saved strings */
   S->nstr++;
   setsvalue(L, &sv, ts);
-  luaH_setint(L, S->h, S->nstr, &sv);
+  luaH_setint(L, S->h, l_castU2S(S->nstr), &sv);
   luaC_objbarrierback(L, obj2gco(S->h), ts);
 }
 
@@ -234,7 +238,7 @@ static void loadConstants (LoadState *S, Proto *f) {
         f->source = NULL;
         break;
       }
-      default: lua_assert(0);
+      default: error(S, "invalid constant");
     }
   }
 }
@@ -391,11 +395,10 @@ LClosure *luaU_undump (lua_State *L, ZIO *Z, const char *name, int fixed) {
   LoadState S;
   LClosure *cl;
   if (*name == '@' || *name == '=')
-    S.name = name + 1;
+    name = name + 1;
   else if (*name == LUA_SIGNATURE[0])
-    S.name = "binary string";
-  else
-    S.name = name;
+    name = "binary string";
+  S.name = name;
   S.L = L;
   S.Z = Z;
   S.fixed = cast_byte(fixed);
diff --git a/lutf8lib.c b/lutf8lib.c
index 4c9784e0..df49c901 100644
--- a/lutf8lib.c
+++ b/lutf8lib.c
@@ -47,7 +47,7 @@ static lua_Integer u_posrelat (lua_Integer pos, size_t len) {
 ** Decode one UTF-8 sequence, returning NULL if byte sequence is
 ** invalid.  The array 'limits' stores the minimum value for each
 ** sequence length, to check for overlong representations. Its first
-** entry forces an error for non-ascii bytes with no continuation
+** entry forces an error for non-ASCII bytes with no continuation
 ** bytes (count == 0).
 */
 static const char *utf8_decode (const char *s, l_uint32 *val, int strict) {
@@ -55,7 +55,7 @@ static const char *utf8_decode (const char *s, l_uint32 *val, int strict) {
         {~(l_uint32)0, 0x80, 0x800, 0x10000u, 0x200000u, 0x4000000u};
   unsigned int c = (unsigned char)s[0];
   l_uint32 res = 0;  /* final result */
-  if (c < 0x80)  /* ascii? */
+  if (c < 0x80)  /* ASCII? */
     res = c;
   else {
     int count = 0;  /* to count number of continuation bytes */
@@ -215,9 +215,10 @@ static int byteoffset (lua_State *L) {
   }
   lua_pushinteger(L, posi + 1);  /* initial position */
   if ((s[posi] & 0x80) != 0) {  /* multi-byte character? */
-    do {
-      posi++;
-    } while (iscontp(s + posi + 1));  /* skip to final byte */
+    if (iscont(s[posi]))
+      return luaL_error(L, "initial position is a continuation byte");
+    while (iscontp(s + posi + 1))
+      posi++;  /* skip to last continuation byte */
   }
   /* else one-byte character: final position is the initial one */
   lua_pushinteger(L, posi + 1);  /* 'posi' now is the final position */
diff --git a/lvm.c b/lvm.c
index e2c36ef5..cfdcf97a 100644
--- a/lvm.c
+++ b/lvm.c
@@ -327,7 +327,7 @@ lu_byte luaV_finishget (lua_State *L, const TValue *t, TValue *key,
 ** Finish a table assignment 't[key] = val'.
 ** About anchoring the table before the call to 'luaH_finishset':
 ** This call may trigger an emergency collection. When loop>0,
-** the table being acessed is a field in some metatable. If this
+** the table being accessed is a field in some metatable. If this
 ** metatable is weak and the table is not anchored, this collection
 ** could collect that table while it is being updated.
 */
@@ -573,52 +573,74 @@ int luaV_lessequal (lua_State *L, const TValue *l, const TValue *r) {
 */
 int luaV_equalobj (lua_State *L, const TValue *t1, const TValue *t2) {
   const TValue *tm;
-  if (ttypetag(t1) != ttypetag(t2)) {  /* not the same variant? */
-    if (ttype(t1) != ttype(t2) || ttype(t1) != LUA_TNUMBER)
-      return 0;  /* only numbers can be equal with different variants */
-    else {  /* two numbers with different variants */
-      /* One of them is an integer. If the other does not have an
-         integer value, they cannot be equal; otherwise, compare their
-         integer values. */
-      lua_Integer i1, i2;
-      return (luaV_tointegerns(t1, &i1, F2Ieq) &&
-              luaV_tointegerns(t2, &i2, F2Ieq) &&
-              i1 == i2);
+  if (ttype(t1) != ttype(t2))  /* not the same type? */
+    return 0;
+  else if (ttypetag(t1) != ttypetag(t2)) {
+    switch (ttypetag(t1)) {
+      case LUA_VNUMINT: {  /* integer == float? */
+        /* integer and float can only be equal if float has an integer
+           value equal to the integer */
+        lua_Integer i2;
+        return (luaV_flttointeger(fltvalue(t2), &i2, F2Ieq) &&
+                ivalue(t1) == i2);
+      }
+      case LUA_VNUMFLT: {  /* float == integer? */
+        lua_Integer i1;  /* see comment in previous case */
+        return (luaV_flttointeger(fltvalue(t1), &i1, F2Ieq) &&
+                i1 == ivalue(t2));
+      }
+      case LUA_VSHRSTR: case LUA_VLNGSTR: {
+        /* compare two strings with different variants: they can be
+           equal when one string is a short string and the other is
+           an external string  */
+        return luaS_eqstr(tsvalue(t1), tsvalue(t2));
+      }
+      default:
+        /* only numbers (integer/float) and strings (long/short) can have
+           equal values with different variants */
+        return 0;
     }
   }
-  /* values have same type and same variant */
-  switch (ttypetag(t1)) {
-    case LUA_VNIL: case LUA_VFALSE: case LUA_VTRUE: return 1;
-    case LUA_VNUMINT: return (ivalue(t1) == ivalue(t2));
-    case LUA_VNUMFLT: return luai_numeq(fltvalue(t1), fltvalue(t2));
-    case LUA_VLIGHTUSERDATA: return pvalue(t1) == pvalue(t2);
-    case LUA_VLCF: return fvalue(t1) == fvalue(t2);
-    case LUA_VSHRSTR: return eqshrstr(tsvalue(t1), tsvalue(t2));
-    case LUA_VLNGSTR: return luaS_eqlngstr(tsvalue(t1), tsvalue(t2));
-    case LUA_VUSERDATA: {
-      if (uvalue(t1) == uvalue(t2)) return 1;
-      else if (L == NULL) return 0;
-      tm = fasttm(L, uvalue(t1)->metatable, TM_EQ);
-      if (tm == NULL)
-        tm = fasttm(L, uvalue(t2)->metatable, TM_EQ);
-      break;  /* will try TM */
+  else {  /* equal variants */
+    switch (ttypetag(t1)) {
+      case LUA_VNIL: case LUA_VFALSE: case LUA_VTRUE:
+        return 1;
+      case LUA_VNUMINT:
+        return (ivalue(t1) == ivalue(t2));
+      case LUA_VNUMFLT:
+        return (fltvalue(t1) == fltvalue(t2));
+      case LUA_VLIGHTUSERDATA: return pvalue(t1) == pvalue(t2);
+      case LUA_VSHRSTR:
+        return eqshrstr(tsvalue(t1), tsvalue(t2));
+      case LUA_VLNGSTR:
+        return luaS_eqstr(tsvalue(t1), tsvalue(t2));
+      case LUA_VUSERDATA: {
+        if (uvalue(t1) == uvalue(t2)) return 1;
+        else if (L == NULL) return 0;
+        tm = fasttm(L, uvalue(t1)->metatable, TM_EQ);
+        if (tm == NULL)
+          tm = fasttm(L, uvalue(t2)->metatable, TM_EQ);
+        break;  /* will try TM */
+      }
+      case LUA_VTABLE: {
+        if (hvalue(t1) == hvalue(t2)) return 1;
+        else if (L == NULL) return 0;
+        tm = fasttm(L, hvalue(t1)->metatable, TM_EQ);
+        if (tm == NULL)
+          tm = fasttm(L, hvalue(t2)->metatable, TM_EQ);
+        break;  /* will try TM */
+      }
+      case LUA_VLCF:
+        return (fvalue(t1) == fvalue(t2));
+      default:  /* functions and threads */
+        return (gcvalue(t1) == gcvalue(t2));
     }
-    case LUA_VTABLE: {
-      if (hvalue(t1) == hvalue(t2)) return 1;
-      else if (L == NULL) return 0;
-      tm = fasttm(L, hvalue(t1)->metatable, TM_EQ);
-      if (tm == NULL)
-        tm = fasttm(L, hvalue(t2)->metatable, TM_EQ);
-      break;  /* will try TM */
+    if (tm == NULL)  /* no TM? */
+      return 0;  /* objects are different */
+    else {
+      int tag = luaT_callTMres(L, tm, t1, t2, L->top.p);  /* call TM */
+      return !tagisfalse(tag);
     }
-    default:
-      return gcvalue(t1) == gcvalue(t2);
-  }
-  if (tm == NULL)  /* no TM? */
-    return 0;  /* objects are different */
-  else {
-    int tag = luaT_callTMres(L, tm, t1, t2, L->top.p);  /* call TM */
-    return !tagisfalse(tag);
   }
 }
 
@@ -700,7 +722,7 @@ void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
       Table *h = hvalue(rb);
       tm = fasttm(L, h->metatable, TM_LEN);
       if (tm) break;  /* metamethod? break switch to call it */
-      setivalue(s2v(ra), l_castU2S(luaH_getn(h)));  /* else primitive len */
+      setivalue(s2v(ra), l_castU2S(luaH_getn(L, h)));  /* else primitive len */
       return;
     }
     case LUA_VSHRSTR: {
diff --git a/manual/2html b/manual/2html
index ac5ea043..b7afd2a6 100755
--- a/manual/2html
+++ b/manual/2html
@@ -8,11 +8,11 @@
 
 ---------------------------------------------------------------
 header = [[
-<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
+<!DOCTYPE html>
 <html>
 
 <head>
-<title>Lua 5.4 Reference Manual</title>
+<title>Lua 5.5 Reference Manual</title>
 <meta http-equiv="Content-Type" content="text/html;charset=utf-8">
 <link rel="stylesheet" href="lua.css">
 <link rel="stylesheet" href="manual.css">
@@ -23,7 +23,7 @@ header = [[
 <hr>
 <h1>
 <a href="http://www.lua.org/home.html"><img src="logo.gif" alt="[Lua logo]" border="0"></a>
-Lua 5.4 Reference Manual
+Lua 5.5 Reference Manual
 </h1>
 
 by Roberto Ierusalimschy, Luiz Henrique de Figueiredo, Waldemar Celes
diff --git a/manual/manual.of b/manual/manual.of
index 7cd0d4db..b2765774 100644
--- a/manual/manual.of
+++ b/manual/manual.of
@@ -213,11 +213,89 @@ of a given value @seeF{type}.
 
 }
 
-@sect2{globalenv| @title{Environments and the Global Environment}
+@sect2{globalenv| @title{Scopes, Variables, and Environments}
+@index{visibility}
+
+A variable name refers to a global or a local variable according
+to the declaration that is in context at that point of the code.
+(For the purposes of this discussion,
+a function's formal parameter is equivalent to a local variable.)
+
+All chunks start with an implicit declaration @T{global *},
+which declares all free names as global variables;
+this preambular declaration becomes void inside the scope of any other
+@Rw{global} declaration,
+as the following example illustrates:
+@verbatim{
+X = 1       -- Ok, global by default
+do
+  global Y  -- voids the implicit initial declaration
+  Y = 1     -- Ok, Y declared as global
+  X = 1     -- ERROR, X not declared
+end
+X = 2       -- Ok, global by default again
+}
+So, outside any global declaration,
+Lua works as @x{global-by-default}.
+Inside any global declaration,
+Lua works without a default:
+All variables must be declared.
+
+Lua is a lexically scoped language.
+The scope of a variable declaration begins at the first statement after
+the declaration and lasts until the last non-void statement
+of the innermost block that includes the declaration.
+(@emph{Void statements} are labels and empty statements.)
+
+A declaration shadows any declaration for the same name that
+is in context at the point of the declaration. Inside this
+shadow, any outer declaration for that name is void.
+See the next example:
+@verbatim{
+global print, x
+x = 10                -- global variable
+do                    -- new block
+  local x = x         -- new 'x', with value 10
+  print(x)            --> 10
+  x = x+1
+  do                  -- another block
+    local x = x+1     -- another 'x'
+    print(x)          --> 12
+  end
+  print(x)            --> 11
+end
+print(x)              --> 10  (the global one)
+}
+
+Notice that, in a declaration like @T{local x = x},
+the new @id{x} being declared is not in scope yet,
+and so the @id{x} in the right-hand side refers to the outside variable.
+
+Because of the @x{lexical scoping} rules,
+local variables can be freely accessed by functions
+defined inside their scope.
+A local variable used by an inner function is called an @def{upvalue}
+(or @emphx{external local variable}, or simply @emphx{external variable})
+inside the inner function.
+
+Notice that each execution of a @Rw{local} statement
+defines new local variables.
+Consider the following example:
+@verbatim{
+a = {}
+local x = 20
+for i = 1, 10 do
+  local y = 0
+  a[i] = function () y = y + 1; return x + y end
+end
+}
+The loop creates ten closures
+(that is, ten instances of the anonymous function).
+Each of these closures uses a different @id{y} variable,
+while all of them share the same @id{x}.
 
 As we will discuss further in @refsec{variables} and @refsec{assignment},
-any reference to a free name
-(that is, a name not bound to any declaration) @id{var}
+any reference to a global variable @id{var}
 is syntactically translated to @T{_ENV.var}.
 Moreover, every chunk is compiled in the scope of
 an external local variable named @id{_ENV} @see{chunks},
@@ -225,12 +303,14 @@ so @id{_ENV} itself is never a free name in a chunk.
 
 Despite the existence of this external @id{_ENV} variable and
 the translation of free names,
-@id{_ENV} is a completely regular name.
+@id{_ENV} is a regular name.
 In particular,
 you can define new variables and parameters with that name.
-Each reference to a free name uses the @id{_ENV} that is
-visible at that point in the program,
-following the usual visibility rules of Lua @see{visibility}.
+(However, you should not define @id{_ENV} as a global variable,
+otherwise @T{_ENV.var} would translate to
+@T{_ENV._ENV.var} and so on, in an infinite loop.)
+Each reference to a global variable name uses the @id{_ENV} that is
+visible at that point in the program.
 
 Any table used as the value of @id{_ENV} is called an @def{environment}.
 
@@ -244,8 +324,8 @@ When Lua loads a chunk,
 the default value for its @id{_ENV} variable
 is the global environment @seeF{load}.
 Therefore, by default,
-free names in Lua code refer to entries in the global environment
-and, therefore, they are also called @def{global variables}.
+global variables in Lua code refer to entries in the global environment
+and, therefore, they act as conventional global variables.
 Moreover, all standard libraries are loaded in the global environment
 and some functions there operate on that environment.
 You can use @Lid{load} (or @Lid{loadfile})
@@ -1031,9 +1111,9 @@ and cannot be used as names:
 @index{reserved words}
 @verbatim{
 and       break     do        else      elseif    end
-false     for       function  goto      if        in
-local     nil       not       or        repeat    return
-then      true      until     while
+false     for       function  global    goto      if
+in        local     nil       not       or        repeat
+return    then      true      until     while
 }
 
 Lua is a case-sensitive language:
@@ -1198,17 +1278,15 @@ global variables, local variables, and table fields.
 
 A single name can denote a global variable or a local variable
 (or a function's formal parameter,
-which is a particular kind of local variable):
+which is a particular kind of local variable) @see{globalenv}:
 @Produc{
 @producname{var}@producbody{@bnfNter{Name}}
 }
 @bnfNter{Name} denotes identifiers @see{lexical}.
 
-Any variable name is assumed to be global unless explicitly declared
-as a local @see{localvar}.
-@x{Local variables} are @emph{lexically scoped}:
+Because variables are @emph{lexically scoped},
 local variables can be freely accessed by functions
-defined inside their scope @see{visibility}.
+defined inside their scope @see{globalenv}.
 
 Before the first assignment to a variable, its value is @nil.
 
@@ -1227,8 +1305,6 @@ The syntax @id{var.Name} is just syntactic sugar for
 
 An access to a global variable @id{x}
 is equivalent to @id{_ENV.x}.
-Due to the way that chunks are compiled,
-the variable @id{_ENV} itself is never global @see{globalenv}.
 
 }
 
@@ -1326,6 +1402,8 @@ Chunks can also be precompiled into binary form;
 see the program @idx{luac} and the function @Lid{string.dump} for details.
 Programs in source and compiled forms are interchangeable;
 Lua automatically detects the file type and acts accordingly @seeF{load}.
+Be aware that, unlike source code,
+maliciously crafted binary chunks can crash the interpreter.
 
 }
 
@@ -1428,7 +1506,7 @@ labels in Lua are considered statements too:
 A label is visible in the entire block where it is defined,
 except inside nested functions.
 A goto can jump to any visible label as long as it does not
-enter into the scope of a local variable.
+enter into the scope of a variable declaration.
 A label should not be declared
 where a previous label with the same name is visible,
 even if this other label has been declared in an enclosing block.
@@ -1571,35 +1649,85 @@ Function calls are explained in @See{functioncall}.
 
 }
 
-@sect3{localvar| @title{Local Declarations}
-@x{Local variables} can be declared anywhere inside a block.
+@sect3{localvar| @title{Variable Declarations}
+Local and global variables can be declared anywhere inside a block.
 The declaration can include an initialization:
 @Produc{
-@producname{stat}@producbody{@Rw{local} attnamelist @bnfopt{@bnfter{=} explist}}
-@producname{attnamelist}@producbody{
-  @bnfNter{Name} attrib @bnfrep{@bnfter{,} @bnfNter{Name} attrib}}
+@producname{stat}@producbody{@Rw{local}
+  attnamelist @bnfopt{@bnfter{=} explist}}
+@producname{stat}@producbody{@Rw{global}
+  attnamelist @bnfopt{@bnfter{=} explist}}
 }
 If present, an initial assignment has the same semantics
 of a multiple assignment @see{assignment}.
-Otherwise, all variables are initialized with @nil.
+Otherwise, all local variables are initialized with @nil.
 
-Each variable name may be postfixed by an attribute
-(a name between angle brackets):
+The list of names may be prefixed by an attribute
+(a name between angle brackets)
+and each variable name may be postfixed by an attribute:
 @Produc{
-@producname{attrib}@producbody{@bnfopt{@bnfter{<} @bnfNter{Name} @bnfter{>}}}
+@producname{attnamelist}@producbody{
+  @bnfopt{attrib} @bnfNter{Name} @bnfopt{attrib}
+     @bnfrep{@bnfter{,} @bnfNter{Name} @bnfopt{attrib}}}
+@producname{attrib}@producbody{@bnfter{<} @bnfNter{Name} @bnfter{>}}
 }
+A prefixed attribute applies to all names in the list;
+a postfixed attribute applies to its particular name.
 There are two possible attributes:
 @id{const}, which declares a @emph{constant} or @emph{read-only} variable,
 @index{constant variable}
-that is, a variable that cannot be assigned to
-after its initialization;
+that is, a variable that cannot be used as the left-hand side of an
+assignment,
 and @id{close}, which declares a to-be-closed variable @see{to-be-closed}.
+Only local variables can have the @id{close} attribute.
 A list of variables can contain at most one to-be-closed variable.
 
+Lua offers also a collective declaration for global variables:
+@Produc{
+@producname{stat}@producbody{@Rw{global} @bnfopt{attrib} @bnfter{*}}
+}
+This special form implicitly declares
+as globals all names not explicitly declared previously.
+In particular,
+@T{global<const> *} implicitly declares
+as read-only globals all names not explicitly declared previously;
+see the following example:
+@verbatim{
+global X
+global<const> *
+print(math.pi)   -- Ok, 'print' and 'math' are read-only
+X = 1            -- Ok, declared as read-write
+Y = 1            -- Error, Y is read-only
+}
+
+As noted in @See{globalenv},
+all chunks start with an implicit declaration @T{global *},
+but this preambular declaration becomes void inside
+the scope of any other @Rw{global} declaration.
+Therefore, a program that does not use global declarations
+or start with @T{global *}
+has free read-write access to any global;
+a program that starts with @T{global<const> *}
+has free read-only access to any global;
+and a program that starts with any other global declaration
+(e.g., @T{global none}) can only refer to declared variables.
+
+Note that, for global variables,
+the effect of any declaration is only syntactical
+(except for the optional assignment):
+@verbatim{
+global X <const>, _G
+X = 1           -- ERROR
+_ENV.X = 1      -- Ok
+_G.print(X)     -- Ok
+foo()         -- 'foo' can freely change any global
+}
+
 A chunk is also a block @see{chunks},
-and so local variables can be declared in a chunk outside any explicit block.
+and so variables can be declared in a chunk outside any explicit block.
 
-The visibility rules for local variables are explained in @See{visibility}.
+The visibility rules for variable declarations
+are explained in @See{globalenv}.
 
 }
 
@@ -2142,6 +2270,7 @@ The following syntactic sugar simplifies function definitions:
 @Produc{
 @producname{stat}@producbody{@Rw{function} funcname funcbody}
 @producname{stat}@producbody{@Rw{local} @Rw{function} @bnfNter{Name} funcbody}
+@producname{stat}@producbody{@Rw{global} @Rw{function} @bnfNter{Name} funcbody}
 @producname{funcname}@producbody{@bnfNter{Name} @bnfrep{@bnfter{.} @bnfNter{Name}} @bnfopt{@bnfter{:} @bnfNter{Name}}}
 }
 The statement
@@ -2160,6 +2289,7 @@ translates to
 @verbatim{
 t.a.b.c.f = function () @rep{body} end
 }
+
 The statement
 @verbatim{
 local function f () @rep{body} end
@@ -2173,7 +2303,15 @@ not to
 local f = function () @rep{body} end
 }
 (This only makes a difference when the body of the function
-contains references to @id{f}.)
+contains recursive references to @id{f}.)
+Similarly, the statement
+@verbatim{
+global function f () @rep{body} end
+}
+translates to
+@verbatim{
+global f; f = function () @rep{body} end
+}
 
 A function definition is an executable expression,
 whose value has type @emph{function}.
@@ -2236,7 +2374,7 @@ then the function returns with no results.
 @index{multiple return}
 There is a system-dependent limit on the number of values
 that a function may return.
-This limit is guaranteed to be greater than 1000.
+This limit is guaranteed to be at least 1000.
 
 The @emphx{colon} syntax
 is used to emulate @def{methods},
@@ -2281,8 +2419,8 @@ for instance @T{foo(e1, e2, e3)} @see{functioncall}.}
 @item{A multiple assignment,
 for instance @T{a , b, c = e1, e2, e3} @see{assignment}.}
 
-@item{A local declaration,
-for instance @T{local a , b, c = e1, e2, e3} @see{localvar}.}
+@item{A local or global declaration,
+which is a special case of multiple assignment.}
 
 @item{The initial values in a generic @rw{for} loop,
 for instance @T{for k in e1, e2, e3 do ... end} @see{for}.}
@@ -2293,8 +2431,7 @@ the list of values from the list of expressions
 must be @emph{adjusted} to a specific length:
 the number of parameters in a call to a non-variadic function
 @see{func-def},
-the number of variables in a multiple assignment or
-a local declaration,
+the number of variables in a multiple assignment or a declaration,
 and exactly four values for a generic @rw{for} loop.
 The @def{adjustment} follows these rules:
 If there are more values than needed,
@@ -2356,58 +2493,6 @@ return x,y,f()     -- returns x, y, and all results from f().
 
 }
 
-@sect2{visibility| @title{Visibility Rules}
-
-@index{visibility}
-Lua is a lexically scoped language.
-The scope of a local variable begins at the first statement after
-its declaration and lasts until the last non-void statement
-of the innermost block that includes the declaration.
-(@emph{Void statements} are labels and empty statements.)
-Consider the following example:
-@verbatim{
-x = 10                -- global variable
-do                    -- new block
-  local x = x         -- new 'x', with value 10
-  print(x)            --> 10
-  x = x+1
-  do                  -- another block
-    local x = x+1     -- another 'x'
-    print(x)          --> 12
-  end
-  print(x)            --> 11
-end
-print(x)              --> 10  (the global one)
-}
-
-Notice that, in a declaration like @T{local x = x},
-the new @id{x} being declared is not in scope yet,
-and so the second @id{x} refers to the outside variable.
-
-Because of the @x{lexical scoping} rules,
-local variables can be freely accessed by functions
-defined inside their scope.
-A local variable used by an inner function is called an @def{upvalue}
-(or @emphx{external local variable}, or simply @emphx{external variable})
-inside the inner function.
-
-Notice that each execution of a @Rw{local} statement
-defines new local variables.
-Consider the following example:
-@verbatim{
-a = {}
-local x = 20
-for i = 1, 10 do
-  local y = 0
-  a[i] = function () y = y + 1; return x + y end
-end
-}
-The loop creates ten closures
-(that is, ten instances of the anonymous function).
-Each of these closures uses a different @id{y} variable,
-while all of them share the same @id{x}.
-
-}
 
 }
 
@@ -3182,17 +3267,25 @@ when called through this function.
 
 Resets a thread, cleaning its call stack and closing all pending
 to-be-closed variables.
-Returns a status code:
+The parameter @id{from} represents the coroutine that is resetting @id{L}.
+If there is no such coroutine,
+this parameter can be @id{NULL}.
+
+Unless @id{L} is equal to @id{from},
+the call returns a status code:
 @Lid{LUA_OK} for no errors in the thread
 (either the original error that stopped the thread or
 errors in closing methods),
 or an error status otherwise.
 In case of error,
-leaves the error object on the top of the stack.
+the error object is put on the top of the stack.
 
-The parameter @id{from} represents the coroutine that is resetting @id{L}.
-If there is no such coroutine,
-this parameter can be @id{NULL}.
+If @id{L} is equal to @id{from},
+it corresponds to a thread closing itself.
+In that case,
+the call does not return;
+instead, the resume that (re)started the thread returns.
+The thread must be running inside a resume.
 
 }
 
@@ -3832,8 +3925,8 @@ This macro may evaluate its arguments more than once.
 
 }
 
-@APIEntry{unsigned (lua_numbertocstring) (lua_State *L, int idx,
-                                          char *buff);|
+@APIEntry{unsigned lua_numbertocstring (lua_State *L, int idx,
+                                        char *buff);|
 @apii{0,0,-}
 
 Converts the number at acceptable index @id{idx} to a string
@@ -3958,7 +4051,7 @@ This function is equivalent to @Lid{lua_pushcclosure} with no upvalues.
 
 }
 
-@APIEntry{const char *(lua_pushexternalstring) (lua_State *L,
+@APIEntry{const char *lua_pushexternalstring (lua_State *L,
                 const char *s, size_t len, lua_Alloc falloc, void *ud);|
 @apii{0,1,m}
 
@@ -3981,11 +4074,6 @@ the string @id{s} as the block,
 the length plus one (to account for the ending zero) as the old size,
 and 0 as the new size.
 
-Lua always @x{internalizes} strings with lengths up to 40 characters.
-So, for strings in that range,
-this function will immediately internalize the string
-and call @id{falloc} to free the buffer.
-
 Even when using an external buffer,
 Lua still has to allocate a header for the string.
 In case of a memory-allocation error,
@@ -6601,11 +6689,10 @@ It may be the string @St{b} (only @x{binary chunk}s),
 or @St{bt} (both binary and text).
 The default is @St{bt}.
 
-It is safe to load malformed binary chunks;
-@id{load} signals an appropriate error.
-However,
-Lua does not check the consistency of the code inside binary chunks;
-running maliciously crafted bytecode can crash the interpreter.
+Lua does not check the consistency of binary chunks.
+Maliciously crafted binary chunks can crash
+the interpreter.
+You can use the @id{mode} parameter to prevent loading binary chunks.
 
 }
 
@@ -6817,7 +6904,7 @@ and @St{userdata}.
 
 A global variable (not a function) that
 holds a string containing the running Lua version.
-The current value of this variable is @St{Lua 5.4}.
+The current value of this variable is @St{Lua 5.5}.
 
 }
 
@@ -6854,18 +6941,26 @@ which come inside the table @defid{coroutine}.
 See @See{coroutine} for a general description of coroutines.
 
 
-@LibEntry{coroutine.close (co)|
+@LibEntry{coroutine.close ([co])|
 
 Closes coroutine @id{co},
 that is,
 closes all its pending to-be-closed variables
 and puts the coroutine in a dead state.
-The given coroutine must be dead or suspended.
-In case of error
+The default for @id{co} is the running coroutine.
+
+The given coroutine must be dead, suspended,
+or be the running coroutine.
+For the running coroutine,
+this function does not return.
+Instead, the resume that (re)started the coroutine returns.
+
+For other coroutines,
+in case of error
 (either the original error that stopped the coroutine or
 errors in closing methods),
-returns @false plus the error object;
-otherwise returns @true.
+this function returns @false plus the error object;
+otherwise ir returns @true.
 
 }
 
@@ -7055,7 +7150,7 @@ to search for a @N{C loader}.
 
 Lua initializes the @N{C path} @Lid{package.cpath} in the same way
 it initializes the Lua path @Lid{package.path},
-using the environment variable @defid{LUA_CPATH_5_4},
+using the environment variable @defid{LUA_CPATH_5_5},
 or the environment variable @defid{LUA_CPATH},
 or a default path defined in @id{luaconf.h}.
 
@@ -7124,7 +7219,7 @@ A string with the path used by @Lid{require}
 to search for a Lua loader.
 
 At start-up, Lua initializes this variable with
-the value of the environment variable @defid{LUA_PATH_5_4} or
+the value of the environment variable @defid{LUA_PATH_5_5} or
 the environment variable @defid{LUA_PATH} or
 with a default path defined in @id{luaconf.h},
 if those environment variables are not defined.
@@ -7495,9 +7590,9 @@ x = string.gsub("4+5 = $return 4+5$", "%$(.-)%$", function (s)
     end)
 -- x="4+5 = 9"
 
-local t = {name="lua", version="5.4"}
+local t = {name="lua", version="5.5"}
 x = string.gsub("$name-$version.tar.gz", "%$(%w+)", t)
--- x="lua-5.4.tar.gz"
+-- x="lua-5.5.tar.gz"
 }
 
 }
@@ -9233,7 +9328,7 @@ when the standard input (@id{stdin}) is a terminal,
 and as @T{lua -} otherwise.
 
 When called without the option @T{-E},
-the interpreter checks for an environment variable @defid{LUA_INIT_5_4}
+the interpreter checks for an environment variable @defid{LUA_INIT_5_5}
 (or @defid{LUA_INIT} if the versioned name is not defined)
 before running any argument.
 If the variable content has the format @T{@At@rep{filename}},
@@ -9408,7 +9503,12 @@ change between versions.
 @itemize{
 
 @item{
-The control variable in @Rw{for} loops are read only.
+The word @Rw{global} is a reserved word.
+Do not use it as a regular name.
+}
+
+@item{
+The control variable in @Rw{for} loops is read only.
 If you need to change it,
 declare a local variable with the same name in the loop body.
 }
@@ -9534,13 +9634,17 @@ and @bnfNter{LiteralString}, see @See{lexical}.)
 @OrNL   @Rw{for} namelist @Rw{in} explist @Rw{do} block @Rw{end}
 @OrNL   @Rw{function} funcname funcbody
 @OrNL   @Rw{local} @Rw{function} @bnfNter{Name} funcbody
+@OrNL   @Rw{global} @Rw{function} @bnfNter{Name} funcbody
 @OrNL   @Rw{local} attnamelist @bnfopt{@bnfter{=} explist}
+@OrNL   @Rw{global} attnamelist
+@OrNL   @Rw{global} @bnfopt{attrib} @bnfter{*}
 }
 
 @producname{attnamelist}@producbody{
-  @bnfNter{Name} attrib @bnfrep{@bnfter{,} @bnfNter{Name} attrib}}
+  @bnfopt{attrib} @bnfNter{Name} @bnfopt{attrib}
+        @bnfrep{@bnfter{,} @bnfNter{Name} @bnfopt{attrib}}}
 
-@producname{attrib}@producbody{@bnfopt{@bnfter{<} @bnfNter{Name} @bnfter{>}}}
+@producname{attrib}@producbody{@bnfter{<} @bnfNter{Name} @bnfter{>}}
 
 @producname{retstat}@producbody{@Rw{return}
                                    @bnfopt{explist} @bnfopt{@bnfter{;}}}
diff --git a/testes/all.lua b/testes/all.lua
index 5c7ebfa5..d3e2f123 100755
--- a/testes/all.lua
+++ b/testes/all.lua
@@ -2,6 +2,10 @@
 -- $Id: testes/all.lua $
 -- See Copyright Notice in file lua.h
 
+global <const> *
+
+global _soft, _port, _nomsg
+global T
 
 local version = "Lua 5.5"
 if _VERSION ~= version then
@@ -34,7 +38,7 @@ if usertests then
 end
 
 -- tests should require debug when needed
-debug = nil
+global debug; debug = nil
 
 
 if usertests then
@@ -71,7 +75,7 @@ do   -- (
 
 -- track messages for tests not performed
 local msgs = {}
-function Message (m)
+global function Message (m)
   if not _nomsg then
     print(m)
     msgs[#msgs+1] = string.sub(m, 3, -3)
diff --git a/testes/api.lua b/testes/api.lua
index 49e3f9b9..b3791654 100644
--- a/testes/api.lua
+++ b/testes/api.lua
@@ -114,7 +114,7 @@ end
 
 -- testing warnings
 T.testC([[
-  warningC "#This shold be a"
+  warningC "#This should be a"
   warningC " single "
   warning "warning"
   warningC "#This should be "
@@ -162,7 +162,7 @@ do  -- test returning more results than fit in the caller stack
 end
 
 
-do  -- testing multipe returns
+do  -- testing multiple returns
   local function foo (n)
     if n > 0 then return n, foo(n - 1) end
   end
@@ -902,7 +902,7 @@ F = function (x)
     assert(T.udataval(A) == B)
     debug.getmetatable(A)    -- just access it
   end
-  A = x   -- ressurect userdata
+  A = x   -- resurrect userdata
   B = udval
   return 1,2,3
 end
diff --git a/testes/attrib.lua b/testes/attrib.lua
index d8b6e0f3..f4156086 100644
--- a/testes/attrib.lua
+++ b/testes/attrib.lua
@@ -308,11 +308,11 @@ else
   _ENV.x, _ENV.y = nil
 end
 
+
 _ENV = _G
 
 
 -- testing preload
-
 do
   local p = package
   package = {}
@@ -331,6 +331,26 @@ do
   assert(type(package.path) == "string")
 end
 
+
+do  print("testing external strings")
+  package.cpath = DC"?"
+  local lib2 = require"lib2-v2"
+  local t = {}
+  for _, len in ipairs{0, 10, 39, 40, 41, 1000} do
+    local str = string.rep("a", len)
+    local str1 = lib2.newstr(str)
+    assert(str == str1)
+    assert(not T or T.hash(str) == T.hash(str1))
+    t[str1] = 20; assert(t[str] == 20 and t[str1] == 20)
+    t[str] = 10; assert(t[str1] == 10)
+    local tt = {[str1] = str1}
+    assert(next(tt) == str1 and next(tt, str1) == nil)
+    assert(tt[str] == str)
+    local str2 = lib2.newstr(str1)
+    assert(str == str2 and t[str2] == 10 and tt[str2] == str)
+  end
+end
+
 print('+')
 
 end  --]
@@ -447,7 +467,7 @@ do
 end
 
 
--- test of large float/integer indices 
+-- test of large float/integer indices
 
 -- compute maximum integer where all bits fit in a float
 local maxint = math.maxinteger
diff --git a/testes/bwcoercion.lua b/testes/bwcoercion.lua
index cd735ab0..0544944d 100644
--- a/testes/bwcoercion.lua
+++ b/testes/bwcoercion.lua
@@ -4,7 +4,7 @@ local strsub = string.sub
 
 local print = print
 
-_ENV = nil
+global none
 
 -- Try to convert a value to an integer, without assuming any coercion.
 local function toint (x)
diff --git a/testes/calls.lua b/testes/calls.lua
index 942fad72..0dacb85a 100644
--- a/testes/calls.lua
+++ b/testes/calls.lua
@@ -1,6 +1,8 @@
 -- $Id: testes/calls.lua $
 -- See Copyright Notice in file lua.h
 
+global <const> *
+
 print("testing functions and calls")
 
 local debug = require "debug"
@@ -22,7 +24,7 @@ assert(not pcall(type))
 
 
 -- testing local-function recursion
-fact = false
+global fact = false
 do
   local res = 1
   local function fact (n)
@@ -63,7 +65,7 @@ a.b.c:f2('k', 12); assert(a.b.c.k == 12)
 
 print('+')
 
-t = nil   -- 'declare' t
+global t = nil   -- 'declare' t
 function f(a,b,c) local d = 'a'; t={a,b,c,d} end
 
 f(      -- this line change must be valid
@@ -75,7 +77,7 @@ assert(t[1] == 1 and t[2] == 2 and t[3] == 3 and t[4] == 'a')
 
 t = nil   -- delete 't'
 
-function fat(x)
+global function fat(x)
   if x <= 1 then return 1
   else return x*load("return fat(" .. x-1 .. ")", "")()
   end
@@ -107,7 +109,7 @@ end
 
 _G.deep = nil   -- "declaration"  (used by 'all.lua')
 
-function deep (n)
+global function deep (n)
   if n>0 then deep(n-1) end
 end
 deep(10)
@@ -352,7 +354,7 @@ assert(not load(function () return true end))
 
 -- small bug
 local t = {nil, "return ", "3"}
-f, msg = load(function () return table.remove(t, 1) end)
+local f, msg = load(function () return table.remove(t, 1) end)
 assert(f() == nil)   -- should read the empty chunk
 
 -- another small bug (in 5.2.1)
@@ -388,7 +390,8 @@ assert(load("return _ENV", nil, nil, 123)() == 123)
 
 
 -- load when _ENV is not first upvalue
-local x; XX = 123
+global XX; local x
+XX = 123
 local function h ()
   local y=x   -- use 'x', so that it becomes 1st upvalue
   return XX   -- global name
diff --git a/testes/closure.lua b/testes/closure.lua
index d3b9f621..0c2e96c0 100644
--- a/testes/closure.lua
+++ b/testes/closure.lua
@@ -1,6 +1,8 @@
 -- $Id: testes/closure.lua $
 -- See Copyright Notice in file lua.h
 
+global <const> *
+
 print "testing closures"
 
 do  -- bug in 5.4.7
diff --git a/testes/code.lua b/testes/code.lua
index 111717ce..380ff70c 100644
--- a/testes/code.lua
+++ b/testes/code.lua
@@ -1,6 +1,8 @@
 -- $Id: testes/code.lua $
 -- See Copyright Notice in file lua.h
 
+global <const> *
+
 if T==nil then
   (Message or print)('\n >>> testC not active: skipping opcode tests <<<\n')
   return
@@ -405,8 +407,8 @@ do   -- tests for table access in upvalues
 end
 
 -- de morgan
-checkequal(function () local a; if not (a or b) then b=a end end,
-           function () local a; if (not a and not b) then b=a end end)
+checkequal(function () local a, b; if not (a or b) then b=a end end,
+           function () local a, b; if (not a and not b) then b=a end end)
 
 checkequal(function (l) local a; return 0 <= a and a <= l end,
            function (l) local a; return not (not(a >= 0) or not(a <= l)) end)
@@ -480,5 +482,23 @@ do   -- basic check for SETLIST
   assert(count == 1)
 end
 
+
+do   print("testing code for integer limits")
+  local function checkints (n)
+    local source = string.format(
+      "local a = {[true] = 0X%x}; return a[true]", n)
+    local f = assert(load(source))
+    checkKlist(f, {n})
+    assert(f() == n)
+    f = load(string.dump(f))
+    assert(f() == n)
+  end
+
+  checkints(math.maxinteger)
+  checkints(math.mininteger)
+  checkints(-1)
+
+end
+
 print 'OK'
 
diff --git a/testes/constructs.lua b/testes/constructs.lua
index 3f6d506f..94f670c7 100644
--- a/testes/constructs.lua
+++ b/testes/constructs.lua
@@ -60,7 +60,7 @@ assert((x>y) and x or y == 2);
 
 assert(1234567890 == tonumber('1234567890') and 1234567890+1 == 1234567891)
 
-do   -- testing operators with diffent kinds of constants
+do   -- testing operators with different kinds of constants
   -- operands to consider:
   --  * fit in register
   --  * constant doesn't fit in register
diff --git a/testes/coroutine.lua b/testes/coroutine.lua
index 17f6ceba..4881d964 100644
--- a/testes/coroutine.lua
+++ b/testes/coroutine.lua
@@ -156,12 +156,12 @@ do
   st, msg = coroutine.close(co)
   assert(st and msg == nil)
 
+  local main = coroutine.running()
 
-  -- cannot close the running coroutine
-  local st, msg = pcall(coroutine.close, coroutine.running())
-  assert(not st and string.find(msg, "running"))
+  -- cannot close 'main'
+  local st, msg = pcall(coroutine.close, main);
+  assert(not st and string.find(msg, "main"))
 
-  local main = coroutine.running()
 
   -- cannot close a "normal" coroutine
   ;(coroutine.wrap(function ()
@@ -169,20 +169,19 @@ do
     assert(not st and string.find(msg, "normal"))
   end))()
 
-  -- cannot close a coroutine while closing it
-  do
+  do   -- close a coroutine while closing it
     local co
     co = coroutine.create(
       function()
         local x <close> = func2close(function()
-            coroutine.close(co)   -- try to close it again
+            coroutine.close(co)   -- close it again
          end)
         coroutine.yield(20)
       end)
     local st, msg = coroutine.resume(co)
     assert(st and msg == 20)
     st, msg = coroutine.close(co)
-    assert(not st and string.find(msg, "running coroutine"))
+    assert(st and msg == nil)
   end
 
   -- to-be-closed variables in coroutines
@@ -289,6 +288,56 @@ do
 end
 
 
+do print("coroutines closing itself")
+  global <const> coroutine, string, os
+  global <const> assert, error, pcall
+
+  local X = nil
+
+  local function new ()
+    return coroutine.create(function (what)
+
+      local <close>var = func2close(function (t, err)
+        if what == "yield" then
+          coroutine.yield()
+        elseif what == "error" then
+          error(200)
+        else
+          X = "Ok"
+          return X
+        end
+      end)
+
+      -- do an unprotected call so that coroutine becomes non-yieldable
+      string.gsub("a", "a", function ()
+        assert(not coroutine.isyieldable())
+        -- do protected calls while non-yieldable, to add recovery
+        -- entries (setjmp) to the stack
+        assert(pcall(pcall, function ()
+          -- 'close' works even while non-yieldable
+          coroutine.close()   -- close itself
+          os.exit(false)   -- not reacheable
+        end))
+      end)
+    end)
+  end
+
+  local co = new()
+  local st, msg = coroutine.resume(co, "ret")
+  assert(st and msg == nil)
+  assert(X == "Ok")
+
+  local co = new()
+  local st, msg = coroutine.resume(co, "error")
+  assert(not st and msg == 200)
+
+  local co = new()
+  local st, msg = coroutine.resume(co, "yield")
+  assert(not st and string.find(msg, "attempt to yield"))
+
+end
+
+
 -- yielding across C boundaries
 
 local co = coroutine.wrap(function()
diff --git a/testes/db.lua b/testes/db.lua
index 3c821ab7..0f174f17 100644
--- a/testes/db.lua
+++ b/testes/db.lua
@@ -349,8 +349,11 @@ end, "crl")
 
 
 function f(a,b)
+ -- declare some globals to check that they don't interfere with 'getlocal'
+  global collectgarbage
   collectgarbage()
   local _, x = debug.getlocal(1, 1)
+  global assert, g, string
   local _, y = debug.getlocal(1, 2)
   assert(x == a and y == b)
   assert(debug.setlocal(2, 3, "pera") == "AA".."AA")
@@ -386,7 +389,9 @@ function g (...)
   f(AAAA,B)
   assert(AAAA == "pera" and B == "manga")
   do
+     global *
      local B = 13
+     global<const> assert
      local x,y = debug.getlocal(1,5)
      assert(x == 'B' and y == 13)
   end
@@ -431,7 +436,7 @@ do
   assert(a == nil and not b)
 end
 
--- testing iteraction between multiple values x hooks
+-- testing interaction between multiple values x hooks
 do
   local function f(...) return 3, ... end
   local count = 0
@@ -587,7 +592,7 @@ t = getupvalues(foo2)
 assert(t.a == 1 and t.b == 2 and t.c == 3)
 assert(debug.setupvalue(foo1, 1, "xuxu") == "b")
 assert(({debug.getupvalue(foo2, 3)})[2] == "xuxu")
--- upvalues of C functions are allways "called" "" (the empty string)
+-- upvalues of C functions are always named "" (the empty string)
 assert(debug.getupvalue(string.gmatch("x", "x"), 1) == "")  
 
 
@@ -701,7 +706,7 @@ assert(debug.traceback(print, 4) == print)
 assert(string.find(debug.traceback("hi", 4), "^hi\n"))
 assert(string.find(debug.traceback("hi"), "^hi\n"))
 assert(not string.find(debug.traceback("hi"), "'debug.traceback'"))
-assert(string.find(debug.traceback("hi", 0), "'debug.traceback'"))
+assert(string.find(debug.traceback("hi", 0), "'traceback'"))
 assert(string.find(debug.traceback(), "^stack traceback:\n"))
 
 do  -- C-function names in traceback
@@ -829,7 +834,7 @@ end
 
 co = coroutine.create(function (x) f(x) end)
 a, b = coroutine.resume(co, 3)
-t = {"'coroutine.yield'", "'f'", "in function <"}
+t = {"'yield'", "'f'", "in function <"}
 while coroutine.status(co) == "suspended" do
   checktraceback(co, t)
   a, b = coroutine.resume(co)
@@ -839,7 +844,7 @@ t[1] = "'error'"
 checktraceback(co, t)
 
 
--- test acessing line numbers of a coroutine from a resume inside
+-- test accessing line numbers of a coroutine from a resume inside
 -- a C function (this is a known bug in Lua 5.0)
 
 local function g(x)
@@ -966,9 +971,9 @@ local debug = require'debug'
 local a = 12  -- a local variable
 
 local n, v = debug.getlocal(1, 1)
-assert(n == "(temporary)" and v == debug)   -- unkown name but known value
+assert(n == "(temporary)" and v == debug)   -- unknown name but known value
 n, v = debug.getlocal(1, 2)
-assert(n == "(temporary)" and v == 12)   -- unkown name but known value
+assert(n == "(temporary)" and v == 12)   -- unknown name but known value
 
 -- a function with an upvalue
 local f = function () local x; return a end
@@ -1018,7 +1023,7 @@ do   -- bug in 5.4.0: line hooks in stripped code
     line = l
   end, "l")
   assert(s() == 2); debug.sethook(nil)
-  assert(line == nil)  -- hook called withoug debug info for 1st instruction
+  assert(line == nil)  -- hook called without debug info for 1st instruction
 end
 
 do   -- tests for 'source' in binary dumps
diff --git a/testes/errors.lua b/testes/errors.lua
index c1c40fec..4230a352 100644
--- a/testes/errors.lua
+++ b/testes/errors.lua
@@ -303,14 +303,14 @@ do
   local f = function (a) return a + 1 end
   f = assert(load(string.dump(f, true)))
   assert(f(3) == 4)
-  checkerr("^%?:%-1:", f, {})
+  checkerr("^%?:%?:", f, {})
 
   -- code with a move to a local var ('OP_MOV A B' with A<B)
   f = function () local a; a = {}; return a + 2 end
   -- no debug info (so that 'a' is unknown)
   f = assert(load(string.dump(f, true)))
   -- symbolic execution should not get lost
-  checkerr("^%?:%-1:.*table value", f)
+  checkerr("^%?:%?:.*table value", f)
 end
 
 
@@ -489,6 +489,14 @@ if not b then
   end
 end]], 5)
 
+lineerror([[
+_ENV = 1
+global function foo ()
+  local a = 10
+  return a
+end
+]], 2)
+
 
 -- bug in 5.4.0
 lineerror([[
@@ -507,7 +515,7 @@ end
 
 
 if not _soft then
-  -- several tests that exaust the Lua stack
+  -- several tests that exhaust the Lua stack
   collectgarbage()
   print"testing stack overflow"
   local C = 0
@@ -734,7 +742,7 @@ assert(c > 255 and string.find(b, "too many upvalues") and
 
 -- local variables
 s = "\nfunction foo ()\n  local "
-for j = 1,300 do
+for j = 1,200 do
   s = s.."a"..j..", "
 end
 s = s.."b\n"
diff --git a/testes/files.lua b/testes/files.lua
index 53edf314..7146ac7c 100644
--- a/testes/files.lua
+++ b/testes/files.lua
@@ -1,6 +1,8 @@
 -- $Id: testes/files.lua $
 -- See Copyright Notice in file lua.h
 
+global <const> *
+
 local debug = require "debug"
 
 local maxint = math.maxinteger
@@ -478,7 +480,7 @@ do print("testing flush")
 end
 
 
--- test for multipe arguments in 'lines'
+-- test for multiple arguments in 'lines'
 io.output(file); io.write"0123456789\n":close()
 for a,b in io.lines(file, 1, 1) do
   if a == "\n" then assert(not b)
@@ -713,7 +715,7 @@ do
 end
 
 
-if T and T.nonblock then
+if T and T.nonblock and not _port then
   print("testing failed write")
 
   -- unable to write anything to /dev/full
@@ -838,13 +840,13 @@ assert(os.date("!\0\0") == "\0\0")
 local x = string.rep("a", 10000)
 assert(os.date(x) == x)
 local t = os.time()
-D = os.date("*t", t)
+global D = os.date("*t", t)
 assert(os.date(string.rep("%d", 1000), t) ==
        string.rep(os.date("%d", t), 1000))
 assert(os.date(string.rep("%", 200)) == string.rep("%", 100))
 
 local function checkDateTable (t)
-  _G.D = os.date("*t", t)
+  D = os.date("*t", t)
   assert(os.time(D) == t)
   load(os.date([[assert(D.year==%Y and D.month==%m and D.day==%d and
     D.hour==%H and D.min==%M and D.sec==%S and
diff --git a/testes/gc.lua b/testes/gc.lua
index 0693837c..62713dac 100644
--- a/testes/gc.lua
+++ b/testes/gc.lua
@@ -288,6 +288,21 @@ x,y,z=nil
 collectgarbage()
 assert(next(a) == string.rep('$', 11))
 
+do   -- invalid mode
+  local a = setmetatable({}, {__mode = 34})
+  collectgarbage()
+end
+
+
+if T then   -- bug since 5.3: all-weak tables are not being revisited
+  T.gcstate("propagate")
+  local t = setmetatable({}, {__mode = "kv"})
+  T.gcstate("enteratomic")   -- 't' was visited
+  setmetatable(t, {__mode = "kv"})
+  T.gcstate("pause")  -- its new metatable is not being visited
+  assert(getmetatable(t).__mode == "kv")
+end
+
 
 -- 'bug' in 5.1
 a = {}
@@ -446,8 +461,8 @@ do   -- tests for string keys in weak tables
   local m = collectgarbage("count")         -- current memory
   local a = setmetatable({}, {__mode = "kv"})
   a[string.rep("a", 2^22)] = 25   -- long string key -> number value
-  a[string.rep("b", 2^22)] = {}   -- long string key -> colectable value
-  a[{}] = 14                     -- colectable key
+  a[string.rep("b", 2^22)] = {}   -- long string key -> collectable value
+  a[{}] = 14                     -- collectable key
   collectgarbage()
   local k, v = next(a)   -- string key with number value preserved
   assert(k == string.rep("a", 2^22) and v == 25)
@@ -459,7 +474,7 @@ do   -- tests for string keys in weak tables
   assert(next(a) == nil)
   -- make sure will not try to compare with dead key
   assert(a[string.rep("b", 100)] == undef)
-  assert(collectgarbage("count") <= m + 1)   -- eveything collected
+  assert(collectgarbage("count") <= m + 1)   -- everything collected
 end
 
 
@@ -524,7 +539,7 @@ do
     local co = coroutine.create(f)
     assert(coroutine.resume(co, co))
   end
-  -- Now, thread and closure are not reacheable any more.
+  -- Now, thread and closure are not reachable any more.
   collectgarbage()
   assert(collected)
   collectgarbage("restart")
@@ -644,7 +659,7 @@ do
     assert(getmetatable(o) == tt)
     -- create new objects during GC
     local a = 'xuxu'..(10+3)..'joao', {}
-    ___Glob = o  -- ressurrect object!
+    ___Glob = o  -- resurrect object!
     setmetatable({}, tt)  -- creates a new one with same metatable
     print(">>> closing state " .. "<<<\n")
   end
diff --git a/testes/goto.lua b/testes/goto.lua
index eca68516..3310314d 100644
--- a/testes/goto.lua
+++ b/testes/goto.lua
@@ -1,6 +1,12 @@
 -- $Id: testes/goto.lua $
 -- See Copyright Notice in file lua.h
 
+global<const> require
+global<const> print, load, assert, string, setmetatable
+global<const> collectgarbage, error
+
+print("testing goto and global declarations")
+
 collectgarbage()
 
 local function errmsg (code, m)
@@ -17,15 +23,18 @@ errmsg([[ ::l1:: ::l1:: ]], "label 'l1'")
 errmsg([[ ::l1:: do ::l1:: end]], "label 'l1'")
 
 
--- undefined label
-errmsg([[ goto l1; local aa ::l1:: ::l2:: print(3) ]], "local 'aa'")
 
--- jumping over variable definition
+-- jumping over variable declaration
+errmsg([[ goto l1; local aa ::l1:: ::l2:: print(3) ]], "scope of 'aa'")
+
+errmsg([[ goto l2; global *; ::l1:: ::l2:: print(3) ]], "scope of '*'")
+
 errmsg([[
 do local bb, cc; goto l1; end
 local aa
 ::l1:: print(3)
-]], "local 'aa'")
+]], "scope of 'aa'")
+
 
 -- jumping into a block
 errmsg([[ do ::l1:: end goto l1 ]], "label 'l1'")
@@ -38,7 +47,7 @@ errmsg([[
     local xuxu = 10
     ::cont::
   until xuxu < x
-]], "local 'xuxu'")
+]], "scope of 'xuxu'")
 
 -- simple gotos
 local x
@@ -252,6 +261,8 @@ assert(testG(5) == 10)
 
 do   -- test goto's around to-be-closed variable
 
+  global *
+
   -- set 'var' and return an object that will reset 'var' when
   -- it goes out of scope
   local function newobj (var)
@@ -263,16 +274,16 @@ do   -- test goto's around to-be-closed variable
 
   goto L1
 
-  ::L4:: assert(not X); goto L5   -- varX dead here
+  ::L4:: assert(not varX); goto L5   -- varX dead here
 
   ::L1::
   local varX <close> = newobj("X")
-  assert(X); goto L2   -- varX alive here
+  assert(varX); goto L2   -- varX alive here
 
   ::L3::
-  assert(X); goto L4   -- varX alive here
+  assert(varX); goto L4   -- varX alive here
 
-  ::L2:: assert(X); goto L3  -- varX alive here
+  ::L2:: assert(varX); goto L3  -- varX alive here
 
   ::L5::   -- return
 end
@@ -280,7 +291,146 @@ end
 
 
 foo()
---------------------------------------------------------------------------------
+--------------------------------------------------------------------------
+
+local function checkerr (code, err)
+  local st, msg = load(code)
+  assert(not st and string.find(msg, err))
+end
+
+do
+  global T<const>
+
+  -- globals must be declared, after a global declaration
+  checkerr("global none; X = 1", "variable 'X'")
+  checkerr("global none; function XX() end", "variable 'XX'")
 
+  -- global variables cannot be to-be-closed
+  checkerr("global X<close>", "cannot be")
+  checkerr("global <close> *", "cannot be")
+
+  do
+    local X = 10
+    do global X; X = 20 end
+    assert(X == 10)   -- local X
+  end
+  assert(_ENV.X == 20)  -- global X
+
+  -- '_ENV' cannot be global
+  checkerr("global _ENV, a; a = 10", "variable 'a'")
+
+  -- global declarations inside functions
+  checkerr([[
+    global none
+    local function foo () XXX = 1 end   --< ERROR]], "variable 'XXX'")
+
+  if not T then  -- when not in "test mode", "global" isn't reserved
+    assert(load("global = 1; return global")() == 1)
+    print "  ('global' is not a reserved word)"
+  else
+    -- "global" reserved, cannot be used as a variable
+    assert(not load("global = 1; return global"))
+  end
+
+  local foo = 20
+  do
+    global function foo (x)
+      if x == 0 then return 1 else return 2 * foo(x - 1) end
+    end
+    assert(foo == _ENV.foo and foo(4) == 16)
+  end
+  assert(_ENV.foo(4) == 16)
+  assert(foo == 20)   -- local one is in context here
+
+  do
+    global foo;
+    function foo (x) return end   -- Ok after declaration
+  end
+
+  checkerr([[
+    global<const> foo;
+    function foo (x) return end   -- ERROR: foo is read-only
+  ]], "assign to const variable 'foo'")
+
+  checkerr([[
+    global foo <const>;
+    function foo (x)    -- ERROR: foo is read-only
+      return
+    end
+  ]], "%:2%:")   -- correct line in error message
+
+  checkerr([[
+    global<const> *;
+    print(X)    -- Ok to use
+    Y = 1   -- ERROR
+  ]], "assign to const variable 'Y'")
+
+  checkerr([[
+    global *;
+    Y = X    -- Ok to use
+    global<const> *;
+    Y = 1   -- ERROR
+  ]], "assign to const variable 'Y'")
+
+  global *
+  Y = 10
+  assert(_ENV.Y == 10)
+  global<const> *
+  local x = Y
+  global *
+  Y = x + Y
+  assert(_ENV.Y == 20)
+  Y = nil
+end
+
+
+do   -- Ok to declare hundreds of globals
+  global table
+  local code = {}
+  for i = 1, 1000 do
+    code[#code + 1] = ";global x" .. i
+  end
+  code[#code + 1] = "; return x990"
+  code = table.concat(code)
+  _ENV.x990 = 11
+  assert(load(code)() == 11)
+  _ENV.x990 = nil
+end
+
+do   -- mixing lots of global/local declarations
+  global table
+  local code = {}
+  for i = 1, 200 do
+    code[#code + 1] = ";global x" .. i
+    code[#code + 1] = ";local y" .. i .. "=" .. (2*i)
+  end
+  code[#code + 1] = "; return x200 + y200"
+  code = table.concat(code)
+  _ENV.x200 = 11
+  assert(assert(load(code))() == 2*200 + 11)
+  _ENV.x200 = nil
+end
+
+do  print "testing initialization in global declarations"
+  global<const> a, b, c = 10, 20, 30
+  assert(_ENV.a == 10 and b == 20 and c == 30)
+
+  global<const> a, b, c = 10
+  assert(_ENV.a == 10 and b == nil and c == nil)
+
+  global table
+  global a, b, c, d = table.unpack{1, 2, 3, 6, 5}
+  assert(_ENV.a == 1 and b == 2 and c == 3 and d == 6)
+
+  local a, b = 100, 200
+  do
+    global a, b = a, b
+  end
+  assert(_ENV.a == 100 and _ENV.b == 200)
+
+
+  _ENV.a, _ENV.b, _ENV.c, _ENV.d = nil   -- erase these globals
+end
 
 print'OK'
+
diff --git a/testes/libs/lib22.c b/testes/libs/lib22.c
index 8e656502..b377cce5 100644
--- a/testes/libs/lib22.c
+++ b/testes/libs/lib22.c
@@ -1,3 +1,7 @@
+/* implementation for lib2-v2 */
+
+#include <string.h>
+
 #include "lua.h"
 #include "lauxlib.h"
 
@@ -8,8 +12,54 @@ static int id (lua_State *L) {
 }
 
 
+struct STR {
+  void *ud;
+  lua_Alloc allocf;
+};
+
+
+static void *t_freestr (void *ud, void *ptr, size_t osize, size_t nsize) {
+  struct STR *blk = (struct STR*)ptr - 1;
+  blk->allocf(blk->ud, blk, sizeof(struct STR) + osize, 0);
+  return NULL;
+}
+
+
+static int newstr (lua_State *L) {
+  size_t len;
+  const char *str = luaL_checklstring(L, 1, &len);
+  void *ud;
+  lua_Alloc allocf = lua_getallocf(L, &ud);
+  struct STR *blk = (struct STR*)allocf(ud, NULL, 0,
+                                        len + 1 + sizeof(struct STR));
+  if (blk == NULL) {  /* allocation error? */
+    lua_pushliteral(L, "not enough memory");
+    lua_error(L);  /* raise a memory error */
+  }
+  blk->ud = ud;  blk->allocf = allocf;
+  memcpy(blk + 1, str, len + 1);
+  lua_pushexternalstring(L, (char *)(blk + 1), len, t_freestr, L);
+  return 1;
+}
+
+
+/*
+** Create an external string and keep it in the registry, so that it
+** will test that the library code is still available (to deallocate
+** this string) when closing the state.
+*/
+static void initstr (lua_State *L) {
+  lua_pushcfunction(L, newstr);
+  lua_pushstring(L,
+     "012345678901234567890123456789012345678901234567890123456789");
+  lua_call(L, 1, 1);  /* call newstr("0123...") */
+  luaL_ref(L, LUA_REGISTRYINDEX);  /* keep string in the registry */
+}
+
+
 static const struct luaL_Reg funcs[] = {
   {"id", id},
+  {"newstr", newstr},
   {NULL, NULL}
 };
 
@@ -18,6 +68,7 @@ LUAMOD_API int luaopen_lib2 (lua_State *L) {
   lua_settop(L, 2);
   lua_setglobal(L, "y");  /* y gets 2nd parameter */
   lua_setglobal(L, "x");  /* x gets 1st parameter */
+  initstr(L);
   luaL_newlib(L, funcs);
   return 1;
 }
diff --git a/testes/literals.lua b/testes/literals.lua
index 28995718..336ef585 100644
--- a/testes/literals.lua
+++ b/testes/literals.lua
@@ -3,6 +3,8 @@
 
 print('testing scanner')
 
+global <const> *
+
 local debug = require "debug"
 
 
diff --git a/testes/locals.lua b/testes/locals.lua
index ccea0a14..02f41980 100644
--- a/testes/locals.lua
+++ b/testes/locals.lua
@@ -1,6 +1,8 @@
 -- $Id: testes/locals.lua $
 -- See Copyright Notice in file lua.h
 
+global <const> *
+
 print('testing local variables and environments')
 
 local debug = require"debug"
@@ -39,9 +41,11 @@ f = nil
 local f
 local x = 1
 
-a = nil
-load('local a = {}')()
-assert(a == nil)
+do
+  global a; a = nil
+  load('local a = {}')()
+  assert(a == nil)
+end
 
 function f (a)
   local _1, _2, _3, _4, _5
@@ -154,7 +158,7 @@ local _ENV = (function (...) return ... end)(_G, dummy)   -- {
 do local _ENV = {assert=assert}; assert(true) end
 local mt = {_G = _G}
 local foo,x
-A = false    -- "declare" A
+global A; A = false    -- "declare" A
 do local _ENV = mt
   function foo (x)
     A = x
@@ -177,20 +181,27 @@ assert(x==20)
 A = nil
 
 
-do   -- constants
+do   print("testing local constants")
+  global assert<const>, load, string, X
+  X = 1   -- not a constant
   local a<const>, b, c<const> = 10, 20, 30
   b = a + c + b    -- 'b' is not constant
   assert(a == 10 and b == 60 and c == 30)
+
   local function checkro (name, code)
     local st, msg = load(code)
     local gab = string.format("attempt to assign to const variable '%s'", name)
     assert(not st and string.find(msg, gab))
   end
+
   checkro("y", "local x, y <const>, z = 10, 20, 30; x = 11; y = 12")
   checkro("x", "local x <const>, y, z <const> = 10, 20, 30; x = 11")
   checkro("z", "local x <const>, y, z <const> = 10, 20, 30; y = 10; z = 11")
-  checkro("foo", "local foo <const> = 10; function foo() end")
-  checkro("foo", "local foo <const> = {}; function foo() end")
+  checkro("foo", "local<const> foo = 10; function foo() end")
+  checkro("foo", "local<const> foo <const> = {}; function foo() end")
+  checkro("foo", "global<const> foo <const>; function foo() end")
+  checkro("XX", "global XX <const>; XX = 10")
+  checkro("XX", "local _ENV; global XX <const>; XX = 10")
 
   checkro("z", [[
     local a, z <const>, b = 10;
@@ -201,11 +212,26 @@ do   -- constants
     local a, var1 <const> = 10;
     function foo() a = 20; z = function () var1 = 12; end  end
   ]])
+
+  checkro("var1", [[
+    global a, var1 <const>, z;
+    local function foo() a = 20; z = function () var1 = 12; end  end
+  ]])
 end
 
 
+
 print"testing to-be-closed variables"
 
+
+do
+  local st, msg = load("local <close> a, b")
+  assert(not st and string.find(msg, "multiple"))
+
+  local st, msg = load("local a<close>, b<close>")
+  assert(not st and string.find(msg, "multiple"))
+end
+
 local function stack(n) n = ((n == 0) or stack(n - 1)) end
 
 local function func2close (f, x, y)
@@ -1162,7 +1188,7 @@ do
   local function open (x)
     numopen = numopen + 1
     return
-      function ()   -- iteraction function
+      function ()   -- iteration function
         x = x - 1
         if x > 0 then return x end
       end,
diff --git a/testes/main.lua b/testes/main.lua
index bf3c898e..dc48dc48 100644
--- a/testes/main.lua
+++ b/testes/main.lua
@@ -90,7 +90,7 @@ prepfile[[
 1, a
 )
 ]]
-RUN('lua - < %s > %s', prog, out)
+RUN('lua - -- < %s > %s', prog, out)
 checkout("1\tnil\n")
 
 RUN('echo "print(10)\nprint(2)\n" | lua > %s', out)
@@ -133,7 +133,7 @@ checkout("-h\n")
 prepfile("print(package.path)")
 
 -- test LUA_PATH
-RUN('env LUA_INIT= LUA_PATH=x lua %s > %s', prog, out)
+RUN('env LUA_INIT= LUA_PATH=x lua -- %s > %s', prog, out)
 checkout("x\n")
 
 -- test LUA_PATH_version
@@ -226,7 +226,7 @@ RUN("lua -l 'str=string' '-lm=math' -e 'print(m.sin(0))' %s > %s", prog, out)
 checkout("0.0\nALO ALO\t20\n")
 
 
--- test module names with version sufix ("libs/lib2-v2")
+-- test module names with version suffix ("libs/lib2-v2")
 RUN("env LUA_CPATH='./libs/?.so' lua -l lib2-v2 -e 'print(lib2.id())' > %s",
     out)
 checkout("true\n")
@@ -347,7 +347,7 @@ checkout("a\n")
 RUN([[lua "-eprint(1)" -ea=3 -e "print(a)" > %s]], out)
 checkout("1\n3\n")
 
--- test iteractive mode
+-- test interactive mode
 prepfile[[
 (6*2-6) -- ===
 a =
@@ -358,7 +358,7 @@ RUN([[lua -e"_PROMPT='' _PROMPT2=''" -i < %s > %s]], prog, out)
 checkprogout("6\n10\n10\n\n")
 
 prepfile("a = [[b\nc\nd\ne]]\na")
-RUN([[lua -e"_PROMPT='' _PROMPT2=''" -i < %s > %s]], prog, out)
+RUN([[lua -e"_PROMPT='' _PROMPT2=''" -i -- < %s > %s]], prog, out)
 checkprogout("b\nc\nd\ne\n\n")
 
 -- input interrupted in continuation line
@@ -488,12 +488,13 @@ assert(not os.remove(out))
 -- invalid options
 NoRun("unrecognized option '-h'", "lua -h")
 NoRun("unrecognized option '---'", "lua ---")
-NoRun("unrecognized option '-Ex'", "lua -Ex")
+NoRun("unrecognized option '-Ex'", "lua -Ex --")
 NoRun("unrecognized option '-vv'", "lua -vv")
 NoRun("unrecognized option '-iv'", "lua -iv")
 NoRun("'-e' needs argument", "lua -e")
 NoRun("syntax error", "lua -e a")
 NoRun("'-l' needs argument", "lua -l")
+NoRun("-i", "lua -- -i")   -- handles -i as a script name
 
 
 if T then   -- test library?
diff --git a/testes/math.lua b/testes/math.lua
index bad8bc5e..0d228d09 100644
--- a/testes/math.lua
+++ b/testes/math.lua
@@ -3,8 +3,15 @@
 
 print("testing numbers and math lib")
 
-local minint <const> = math.mininteger
-local maxint <const> = math.maxinteger
+local math = require "math"
+local string = require "string"
+
+global none
+
+global<const> print, assert, pcall, type, pairs, load
+global<const> tonumber, tostring, select
+
+local<const> minint, maxint = math.mininteger, math.maxinteger
 
 local intbits <const> = math.floor(math.log(maxint, 2) + 0.5) + 1
 assert((1 << intbits) == 0)
@@ -184,7 +191,7 @@ do
   for i = -3, 3 do    -- variables avoid constant folding
       for j = -3, 3 do
         -- domain errors (0^(-n)) are not portable
-        if not _port or i ~= 0 or j > 0 then
+        if not _ENV._port or i ~= 0 or j > 0 then
           assert(eq(i^j, 1 / i^(-j)))
        end
     end
@@ -430,7 +437,7 @@ for i = 2,36 do
   assert(tonumber('\t10000000000\t', i) == i10)
 end
 
-if not _soft then
+if not _ENV._soft then
   -- tests with very long numerals
   assert(tonumber("0x"..string.rep("f", 13)..".0") == 2.0^(4*13) - 1)
   assert(tonumber("0x"..string.rep("f", 150)..".0") == 2.0^(4*150) - 1)
@@ -632,7 +639,7 @@ assert(maxint % -2 == -1)
 
 -- non-portable tests because Windows C library cannot compute 
 -- fmod(1, huge) correctly
-if not _port then
+if not _ENV._port then
   local function anan (x) assert(isNaN(x)) end   -- assert Not a Number
   anan(0.0 % 0)
   anan(1.3 % 0)
@@ -779,6 +786,7 @@ assert(a == '10' and b == '20')
 
 do
   print("testing -0 and NaN")
+  global rawset, undef
   local mz <const> = -0.0
   local z <const> = 0.0
   assert(mz == z)
@@ -1071,9 +1079,10 @@ do
     assert(x == tonumber(tostring(x)))
   end
 
-  -- different numbers shold print differently.
+  -- different numbers should print differently.
   -- check pairs of floats with minimum detectable difference
   local p = floatbits - 1
+  global ipairs
   for i = 1, maxexp - 1 do
     for _, i in ipairs{-i, i} do
       local x = 2^i
diff --git a/testes/nextvar.lua b/testes/nextvar.lua
index 031ad3fd..7e5bed56 100644
--- a/testes/nextvar.lua
+++ b/testes/nextvar.lua
@@ -1,6 +1,8 @@
 -- $Id: testes/nextvar.lua $
 -- See Copyright Notice in file lua.h
 
+global <const> *
+
 print('testing tables, next, and for')
 
 local function checkerror (msg, f, ...)
@@ -227,7 +229,7 @@ for i = 1,lim do
 end
 
 
--- insert and delete elements until a rehash occurr. Caller must ensure
+-- insert and delete elements until a rehash occur. Caller must ensure
 -- that a rehash will change the shape of the table. Must repeat because
 -- the insertion may collide with the deleted element, and then there is
 -- no rehash.
@@ -343,13 +345,22 @@ do
   end
 end
 
-local nofind = {}
 
-a,b,c = 1,2,3
-a,b,c = nil
+do  print("testing attack on table length")
+  local t = {}
+  local lim = math.floor(math.log(math.maxinteger, 2)) - 1
+  for i = lim, 0, -1 do
+    t[2^i] = true
+  end
+  assert(t[1 << lim])
+  -- next loop should not take forever
+  for i = 1, #t do end
+end
+
+local nofind = {}
 
 
--- next uses always the same iteraction function
+-- next uses always the same iteration function
 assert(next{} == next{})
 
 local function find (name)
@@ -396,7 +407,7 @@ for i=0,10000 do
   end
 end
 
-n = {n=0}
+local n = {n=0}
 for i,v in pairs(a) do
   n.n = n.n+1
   assert(i and v and a[i] == v)
diff --git a/testes/pm.lua b/testes/pm.lua
index 2a0cfb0b..720d2a35 100644
--- a/testes/pm.lua
+++ b/testes/pm.lua
@@ -6,6 +6,8 @@
 
 print('testing pattern matching')
 
+global <const> *
+
 local function checkerror (msg, f, ...)
   local s, err = pcall(f, ...)
   assert(not s and string.find(err, msg))
@@ -23,9 +25,9 @@ a,b = string.find('alo', '')
 assert(a == 1 and b == 0)
 a,b = string.find('a\0o a\0o a\0o', 'a', 1)   -- first position
 assert(a == 1 and b == 1)
-a,b = string.find('a\0o a\0o a\0o', 'a\0o', 2)   -- starts in the midle
+a,b = string.find('a\0o a\0o a\0o', 'a\0o', 2)   -- starts in the middle
 assert(a == 5 and b == 7)
-a,b = string.find('a\0o a\0o a\0o', 'a\0o', 9)   -- starts in the midle
+a,b = string.find('a\0o a\0o a\0o', 'a\0o', 9)   -- starts in the middle
 assert(a == 9 and b == 11)
 a,b = string.find('a\0a\0a\0a\0\0ab', '\0ab', 2);  -- finds at the end
 assert(a == 9 and b == 11);
diff --git a/testes/strings.lua b/testes/strings.lua
index ce28e4c5..46912d43 100644
--- a/testes/strings.lua
+++ b/testes/strings.lua
@@ -3,6 +3,7 @@
 
 -- ISO Latin encoding
 
+global <const> *
 
 print('testing strings and string library')
 
diff --git a/testes/tracegc.lua b/testes/tracegc.lua
index 9c5c1b3f..a8c929df 100644
--- a/testes/tracegc.lua
+++ b/testes/tracegc.lua
@@ -6,7 +6,7 @@ local M = {}
 local setmetatable, stderr, collectgarbage =
          setmetatable, io.stderr, collectgarbage
 
-_ENV = nil
+global none
 
 local active = false
 
diff --git a/testes/utf8.lua b/testes/utf8.lua
index 0704782c..028995a4 100644
--- a/testes/utf8.lua
+++ b/testes/utf8.lua
@@ -3,6 +3,8 @@
 
 -- UTF-8 file
 
+global <const> *
+
 print "testing UTF-8 library"
 
 local utf8 = require'utf8'
@@ -134,7 +136,7 @@ do
   errorcodes("\xbfinvalid")
   errorcodes("αλφ\xBFα")
 
-  -- calling interation function with invalid arguments
+  -- calling iteration function with invalid arguments
   local f = utf8.codes("")
   assert(f("", 2) == nil)
   assert(f("", -1) == nil)
@@ -150,11 +152,20 @@ checkerror("position out of bounds", utf8.offset, "", 1, -1)
 checkerror("continuation byte", utf8.offset, "𦧺", 1, 2)
 checkerror("continuation byte", utf8.offset, "𦧺", 1, 2)
 checkerror("continuation byte", utf8.offset, "\x80", 1)
+checkerror("continuation byte", utf8.offset, "\x9c", -1)
 
 -- error in indices for len
 checkerror("out of bounds", utf8.len, "abc", 0, 2)
 checkerror("out of bounds", utf8.len, "abc", 1, 4)
 
+do  -- missing continuation bytes
+  -- get what is available
+  local p, e = utf8.offset("\xE0", 1)
+  assert(p == 1 and e == 1)
+  local p, e = utf8.offset("\xE0\x9e", -1)
+  assert(p == 1 and e == 2)
+end
+
 
 local s = "hello World"
 local t = {string.byte(s, 1, -1)}