15 files changed, 81 insertions, 22 deletions

diff --git a/lcode.c b/lcode.c
index d00038dd..e84b85ac 100644
--- a/lcode.c
+++ b/lcode.c
@@ -1673,13 +1673,13 @@ void luaK_finish (FuncState *fs) {
     lua_assert(i == 0 || isOT(*(pc - 1)) == isIT(*pc));
     switch (GET_OPCODE(*pc)) {
       case OP_RETURN0: case OP_RETURN1: {
-        if (p->sizep == 0 && !p->is_vararg)
+        if (!(fs->needclose || p->is_vararg))
           break;  /* no extra work */
         /* else use OP_RETURN to do the extra work */
         SET_OPCODE(*pc, OP_RETURN);
       }  /* FALLTHROUGH */
       case OP_RETURN: case OP_TAILCALL: {
-        if (p->sizep > 0 || p->is_vararg) {
+        if (fs->needclose || p->is_vararg) {
           SETARG_C(*pc, p->is_vararg ? p->numparams + 1 : 0);
           SETARG_k(*pc, 1);  /* signal that there is extra work */
         }
diff --git a/ldo.c b/ldo.c
index 0d68d36c..2349aaed 100644
--- a/ldo.c
+++ b/ldo.c
@@ -91,8 +91,7 @@ struct lua_longjmp {
 static void seterrorobj (lua_State *L, int errcode, StkId oldtop) {
   switch (errcode) {
     case LUA_ERRMEM: {  /* memory error? */
-      TString *memerrmsg = luaS_newliteral(L, MEMERRMSG);
-      setsvalue2s(L, oldtop, memerrmsg); /* reuse preregistered msg. */
+      setsvalue2s(L, oldtop, G(L)->memerrmsg); /* reuse preregistered msg. */
       break;
     }
     case LUA_ERRERR: {
diff --git a/lgc.c b/lgc.c
index e8429e1b..39b3ab73 100644
--- a/lgc.c
+++ b/lgc.c
@@ -293,7 +293,8 @@ static void reallymarkobject (global_State *g, GCObject *o) {
       gray2black(o);
       break;
     }
-    case LUA_TUPVAL: {
+    case LUA_TUPVAL:
+    case LUA_TUPVALTBC: {
       UpVal *uv = gco2upv(o);
       if (!upisopen(uv))  /* open upvalues are kept gray */
         gray2black(o);
@@ -760,6 +761,7 @@ static void freeobj (lua_State *L, GCObject *o) {
       luaF_freeproto(L, gco2p(o));
       break;
     case LUA_TUPVAL:
+    case LUA_TUPVALTBC:
       freeupval(L, gco2upv(o));
       break;
     case LUA_TLCL:
diff --git a/ljumptab.h b/ljumptab.h
index c775f10a..da4cf7b7 100644
--- a/ljumptab.h
+++ b/ljumptab.h
@@ -74,6 +74,7 @@ static void *disptab[] = {
 &&L_OP_LEN,
 &&L_OP_CONCAT,
 &&L_OP_CLOSE,
+&&L_OP_TBC,
 &&L_OP_JMP,
 &&L_OP_EQ,
 &&L_OP_LT,
diff --git a/lobject.h b/lobject.h
index ddcf609c..ea3511de 100644
--- a/lobject.h
+++ b/lobject.h
@@ -588,6 +588,10 @@ typedef struct UpVal {
 } UpVal;
 
 
+/* variant for "To Be Closed" upvalues */
+#define LUA_TUPVALTBC   (LUA_TUPVAL | (1 << 4))
+
+
 #define ClosureHeader \
         CommonHeader; lu_byte nupvalues; GCObject *gclist
 
diff --git a/lopcodes.c b/lopcodes.c
index 95347b27..f6915beb 100644
--- a/lopcodes.c
+++ b/lopcodes.c
@@ -68,6 +68,7 @@ LUAI_DDEF const lu_byte luaP_opmodes[NUM_OPCODES] = {
  ,opmode(0, 0, 0, 1, iABC)              /* OP_LEN */
  ,opmode(0, 0, 0, 1, iABC)              /* OP_CONCAT */
  ,opmode(0, 0, 0, 0, iABC)              /* OP_CLOSE */
+ ,opmode(0, 0, 0, 0, iABC)              /* OP_TBC */
  ,opmode(0, 0, 0, 0, isJ)               /* OP_JMP */
  ,opmode(0, 0, 1, 0, iABC)              /* OP_EQ */
  ,opmode(0, 0, 1, 0, iABC)              /* OP_LT */
diff --git a/lopcodes.h b/lopcodes.h
index 9442a336..4d144000 100644
--- a/lopcodes.h
+++ b/lopcodes.h
@@ -251,6 +251,7 @@ OP_LEN,/*	A B	R(A) := length of R(B)				*/
 OP_CONCAT,/*    A B     R(A) := R(A).. ... ..R(A + B - 1)               */
 
 OP_CLOSE,/*     A       close all upvalues >= R(A)                      */
+OP_TBC,/*       A       mark variable A "to be closed"                  */
 OP_JMP,/*       k sJ    pc += sJ  (k is used in code generation)        */
 OP_EQ,/*        A B     if ((R(A) == R(B)) ~= k) then pc++              */
 OP_LT,/*        A B     if ((R(A) <  R(B)) ~= k) then pc++              */
diff --git a/lopnames.h b/lopnames.h
index c40eaeae..304d3b6c 100644
--- a/lopnames.h
+++ b/lopnames.h
@@ -59,6 +59,7 @@ static const char *const opnames[] = {
   "LEN",
   "CONCAT",
   "CLOSE",
+  "TBC",
   "JMP",
   "EQ",
   "LT",
diff --git a/lparser.c b/lparser.c
index 32500b02..84abeb90 100644
--- a/lparser.c
+++ b/lparser.c
@@ -255,6 +255,7 @@ static void markupval (FuncState *fs, int level) {
   while (bl->nactvar > level)
     bl = bl->previous;
   bl->upval = 1;
+  fs->needclose = 1;
 }
 
 
@@ -547,6 +548,7 @@ static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) {
   fs->nups = 0;
   fs->nlocvars = 0;
   fs->nactvar = 0;
+  fs->needclose = 0;
   fs->firstlocal = ls->dyd->actvar.n;
   fs->bl = NULL;
   f->source = ls->source;
@@ -1509,15 +1511,16 @@ static void localfunc (LexState *ls) {
 }
 
 
-static void localstat (LexState *ls) {
+static void commonlocalstat (LexState *ls, TString *firstvar) {
   /* stat -> LOCAL NAME {',' NAME} ['=' explist] */
-  int nvars = 0;
+  int nvars = 1;
   int nexps;
   expdesc e;
-  do {
+  new_localvar(ls, firstvar);
+  while (testnext(ls, ',')) {
     new_localvar(ls, str_checkname(ls));
     nvars++;
-  } while (testnext(ls, ','));
+  }
   if (testnext(ls, '='))
     nexps = explist(ls, &e);
   else {
@@ -1529,6 +1532,29 @@ static void localstat (LexState *ls) {
 }
 
 
+static void scopedlocalstat (LexState *ls) {
+  FuncState *fs = ls->fs;
+  new_localvar(ls, str_checkname(ls));
+  checknext(ls, '=');
+  luaK_codeABC(fs, OP_TBC, fs->nactvar, 0, 0);
+  markupval(fs, fs->nactvar);
+  exp1(ls, 0);
+  adjustlocalvars(ls, 1);
+}
+
+
+static void localstat (LexState *ls) {
+  /* stat -> LOCAL NAME {',' NAME} ['=' explist]
+           | LOCAL SCOPED NAME '=' exp */
+  TString *firstvar = str_checkname(ls);
+  if (ls->t.token == TK_NAME &&
+      eqshrstr(firstvar, luaS_newliteral(ls->L, "scoped")))
+    scopedlocalstat(ls);
+  else
+    commonlocalstat(ls, firstvar);
+}
+
+
 static int funcname (LexState *ls, expdesc *v) {
   /* funcname -> NAME {fieldsel} [':' NAME] */
   int ismethod = 0;
diff --git a/lparser.h b/lparser.h
index e158c9d9..1b94a97a 100644
--- a/lparser.h
+++ b/lparser.h
@@ -133,6 +133,7 @@ typedef struct FuncState {
   lu_byte nups;  /* number of upvalues */
   lu_byte freereg;  /* first free register */
   lu_byte iwthabs;  /* instructions issued since last absolute line info */
+  lu_byte needclose;  /* function needs to close upvalues when returning */
 } FuncState;
 
 
diff --git a/lstate.h b/lstate.h
index 5461b291..f08c2355 100644
--- a/lstate.h
+++ b/lstate.h
@@ -267,7 +267,8 @@ union GCUnion {
 #define gco2t(o)  check_exp((o)->tt == LUA_TTABLE, &((cast_u(o))->h))
 #define gco2p(o)  check_exp((o)->tt == LUA_TPROTO, &((cast_u(o))->p))
 #define gco2th(o)  check_exp((o)->tt == LUA_TTHREAD, &((cast_u(o))->th))
-#define gco2upv(o)  check_exp((o)->tt == LUA_TUPVAL, &((cast_u(o))->upv))
+#define gco2upv(o)  \
+        check_exp(novariant((o)->tt) == LUA_TUPVAL, &((cast_u(o))->upv))
 
 
 /*
diff --git a/ltests.c b/ltests.c
index bc71d937..ff962543 100644
--- a/ltests.c
+++ b/ltests.c
@@ -357,7 +357,8 @@ static void checkrefs (global_State *g, GCObject *o) {
       checkudata(g, gco2u(o));
       break;
     }
-    case LUA_TUPVAL: {
+    case LUA_TUPVAL:
+    case LUA_TUPVALTBC: {
       checkvalref(g, o, gco2upv(o)->v);
       break;
     }
@@ -522,35 +523,37 @@ int lua_checkmemory (lua_State *L) {
 
 
 static char *buildop (Proto *p, int pc, char *buff) {
+  char *obuff = buff;
   Instruction i = p->code[pc];
   OpCode o = GET_OPCODE(i);
   const char *name = opnames[o];
   int line = luaG_getfuncline(p, pc);
   int lineinfo = (p->lineinfo != NULL) ? p->lineinfo[pc] : 0;
-  sprintf(buff, "(%2d - %4d) %4d - ", lineinfo, line, pc);
+  if (lineinfo == ABSLINEINFO)
+    buff += sprintf(buff, "(__");
+  else
+    buff += sprintf(buff, "(%2d", lineinfo);
+  buff += sprintf(buff, " - %4d) %4d - ", line, pc);
   switch (getOpMode(o)) {
     case iABC:
-      sprintf(buff+strlen(buff), "%-12s%4d %4d %4d%s", name,
+      sprintf(buff, "%-12s%4d %4d %4d%s", name,
               GETARG_A(i), GETARG_B(i), GETARG_C(i),
               GETARG_k(i) ? " (k)" : "");
       break;
     case iABx:
-      sprintf(buff+strlen(buff), "%-12s%4d %4d", name, GETARG_A(i),
-                                                       GETARG_Bx(i));
+      sprintf(buff, "%-12s%4d %4d", name, GETARG_A(i), GETARG_Bx(i));
       break;
     case iAsBx:
-      sprintf(buff+strlen(buff), "%-12s%4d %4d", name, GETARG_A(i),
-                                                       GETARG_sBx(i));
+      sprintf(buff, "%-12s%4d %4d", name, GETARG_A(i), GETARG_sBx(i));
       break;
     case iAx:
-      sprintf(buff+strlen(buff), "%-12s%4d", name, GETARG_Ax(i));
+      sprintf(buff, "%-12s%4d", name, GETARG_Ax(i));
       break;
     case isJ:
-      sprintf(buff+strlen(buff), "%-12s%4d (%1d)", name, GETARG_sJ(i),
-                                                         !!GETARG_m(i));
+      sprintf(buff, "%-12s%4d (%1d)", name, GETARG_sJ(i), !!GETARG_m(i));
       break;
   }
-  return buff;
+  return obuff;
 }
 
 
diff --git a/lvm.c b/lvm.c
index dd6a660b..fdd99a42 100644
--- a/lvm.c
+++ b/lvm.c
@@ -1455,6 +1455,12 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
         luaF_close(L, ra);
         vmbreak;
       }
+      vmcase(OP_TBC) {
+        UpVal *up = luaF_findupval(L, ra);  /* create new upvalue */
+        up->tt = LUA_TUPVALTBC;  /* mark it to be closed */
+        setnilvalue(s2v(ra));  /* intialize it with nil */
+        vmbreak;
+      }
       vmcase(OP_JMP) {
         dojump(ci, i, 0);
         vmbreak;
diff --git a/testes/code.lua b/testes/code.lua
index 6bd6ebfa..ad484485 100644
--- a/testes/code.lua
+++ b/testes/code.lua
@@ -64,8 +64,12 @@ end
 
 
 -- some basic instructions
-check(function ()
+check(function ()   -- function does not create upvalues
   (function () end){f()}
+end, 'CLOSURE', 'NEWTABLE', 'GETTABUP', 'CALL', 'SETLIST', 'CALL', 'RETURN0')
+
+check(function (x)   -- function creates upvalues
+  (function () return x end){f()}
 end, 'CLOSURE', 'NEWTABLE', 'GETTABUP', 'CALL', 'SETLIST', 'CALL', 'RETURN')
 
 
diff --git a/testes/locals.lua b/testes/locals.lua
index 14e49a7c..20ecae4b 100644
--- a/testes/locals.lua
+++ b/testes/locals.lua
@@ -173,6 +173,15 @@ end
 assert(x==20)
 
 
+-- tests for to-be-closed variables
+do
+  local scoped x = 3
+  local a
+  local scoped y = 5
+  assert(x == 3 and y == 5)
+end
+
+
 print('OK')
 
 return 5,f