diff --git a/lcode.c b/lcode.c
index e57ad284..40efcff3 100644
--- a/lcode.c
+++ b/lcode.c
@@ -81,9 +81,8 @@ int luaK_exp2const (FuncState *fs, const expdesc *e, TValue *v) {
     case VNIL:
       setnilvalue(v);
       return 1;
-    case VK: {
-      TValue *k = &fs->f->k[e->u.info];
-      setobj(fs->ls->L, v, k);
+    case VKSTR: {
+      setsvalue(fs->ls->L, v, e->u.strval);
       return 1;
     }
     default: return tonumeral(e, v);
@@ -561,7 +560,7 @@ static int addk (FuncState *fs, TValue *key, TValue *v) {
 /*
 ** Add a string to list of constants and return its index.
 */
-int luaK_stringK (FuncState *fs, TString *s) {
+static int stringK (FuncState *fs, TString *s) {
   TValue o;
   setsvalue(fs->ls->L, &o, s);
   return addk(fs, &o, &o);  /* use string itself as key */
@@ -656,7 +655,7 @@ static void luaK_float (FuncState *fs, int reg, lua_Number f) {
 /*
 ** Convert a constant in 'v' into an expression description 'e'
 */
-static void const2exp (FuncState *fs, TValue *v, expdesc *e) {
+static void const2exp (TValue *v, expdesc *e) {
   switch (ttypetag(v)) {
     case LUA_TNUMINT:
       e->k = VKINT; e->u.ival = ivalue(v);
@@ -671,7 +670,7 @@ static void const2exp (FuncState *fs, TValue *v, expdesc *e) {
       e->k = VNIL;
       break;
     case LUA_TSHRSTR:  case LUA_TLNGSTR:
-      e->k = VK; e->u.info = luaK_stringK(fs, tsvalue(v));
+      e->k = VKSTR; e->u.strval = tsvalue(v);
       break;
     default: lua_assert(0);
   }
@@ -696,6 +695,16 @@ void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {
 }
 
 
+/*
+** Convert a VKSTR to a VK
+*/
+static void str2K (FuncState *fs, expdesc *e) {
+  lua_assert(e->k == VKSTR);
+  e->u.info = stringK(fs, e->u.strval);
+  e->k = VK;
+}
+
+
 /*
 ** Fix an expression to return one result.
 ** If expression is not a multi-ret expression (function call or
@@ -728,7 +737,7 @@ void luaK_dischargevars (FuncState *fs, expdesc *e) {
   switch (e->k) {
     case VCONST: {
       TValue *val = &fs->ls->dyd->actvar.arr[e->u.info].k;
-      const2exp(fs, val, e);
+      const2exp(val, e);
       break;
     }
     case VLOCAL: {  /* already in a register */
@@ -789,6 +798,9 @@ static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
       luaK_codeABC(fs, OP_LOADBOOL, reg, e->k == VTRUE, 0);
       break;
     }
+    case VKSTR: {
+      str2K(fs, e);
+    }  /* FALLTHROUGH */
     case VK: {
       luaK_codek(fs, reg, e->u.info);
       break;
@@ -949,6 +961,7 @@ static int luaK_exp2K (FuncState *fs, expdesc *e) {
       case VNIL: info = nilK(fs); break;
       case VKINT: info = luaK_intK(fs, e->u.ival); break;
       case VKFLT: info = luaK_numberK(fs, e->u.nval); break;
+      case VKSTR: info = stringK(fs, e->u.strval); break;
       case VK: info = e->u.info; break;
       default: return 0;  /* not a constant */
     }
@@ -1083,7 +1096,7 @@ void luaK_goiftrue (FuncState *fs, expdesc *e) {
       pc = e->u.info;  /* save jump position */
       break;
     }
-    case VK: case VKFLT: case VKINT: case VTRUE: {
+    case VK: case VKFLT: case VKINT: case VKSTR: case VTRUE: {
       pc = NO_JUMP;  /* always true; do nothing */
       break;
     }
@@ -1133,7 +1146,7 @@ static void codenot (FuncState *fs, expdesc *e) {
       e->k = VTRUE;  /* true == not nil == not false */
       break;
     }
-    case VK: case VKFLT: case VKINT: case VTRUE: {
+    case VK: case VKFLT: case VKINT: case VKSTR: case VTRUE: {
       e->k = VFALSE;  /* false == not "x" == not 0.5 == not 1 == not true */
       break;
     }
@@ -1219,9 +1232,11 @@ static int isSCnumber (expdesc *e, lua_Integer *i, int *isfloat) {
 ** values in registers.
 */
 void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {
+  if (k->k == VKSTR)
+    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 string? */
+  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) {
     t->u.ind.t = t->u.info;  /* upvalue index */
diff --git a/lcode.h b/lcode.h
index 0c12bb64..8cecd538 100644
--- a/lcode.h
+++ b/lcode.h
@@ -62,7 +62,6 @@ LUAI_FUNC void luaK_fixline (FuncState *fs, int line);
 LUAI_FUNC void luaK_nil (FuncState *fs, int from, int n);
 LUAI_FUNC void luaK_reserveregs (FuncState *fs, int n);
 LUAI_FUNC void luaK_checkstack (FuncState *fs, int n);
-LUAI_FUNC int luaK_stringK (FuncState *fs, TString *s);
 LUAI_FUNC void luaK_int (FuncState *fs, int reg, lua_Integer n);
 LUAI_FUNC void luaK_dischargevars (FuncState *fs, expdesc *e);
 LUAI_FUNC int luaK_exp2anyreg (FuncState *fs, expdesc *e);
diff --git a/lparser.c b/lparser.c
index ea810006..b70c609e 100644
--- a/lparser.c
+++ b/lparser.c
@@ -156,13 +156,15 @@ static void init_exp (expdesc *e, expkind k, int i) {
 }
 
 
-static void codestring (LexState *ls, expdesc *e, TString *s) {
-  init_exp(e, VK, luaK_stringK(ls->fs, s));
+static void codestring (expdesc *e, TString *s) {
+  e->f = e->t = NO_JUMP;
+  e->k = VKSTR;
+  e->u.strval = s;
 }
 
 
 static void codename (LexState *ls, expdesc *e) {
-  codestring(ls, e, str_checkname(ls));
+  codestring(e, str_checkname(ls));
 }
 
 
@@ -445,7 +447,7 @@ static void singlevar (LexState *ls, expdesc *var) {
     expdesc key;
     singlevaraux(fs, ls->envn, var, 1);  /* get environment variable */
     lua_assert(var->k != VVOID);  /* this one must exist */
-    codestring(ls, &key, varname);  /* key is variable name */
+    codestring(&key, varname);  /* key is variable name */
     luaK_indexed(fs, var, &key);  /* env[varname] */
   }
 }
@@ -1019,7 +1021,7 @@ static void funcargs (LexState *ls, expdesc *f, int line) {
       break;
     }
     case TK_STRING: {  /* funcargs -> STRING */
-      codestring(ls, &args, ls->t.seminfo.ts);
+      codestring(&args, ls->t.seminfo.ts);
       luaX_next(ls);  /* must use 'seminfo' before 'next' */
       break;
     }
@@ -1127,7 +1129,7 @@ static void simpleexp (LexState *ls, expdesc *v) {
       break;
     }
     case TK_STRING: {
-      codestring(ls, v, ls->t.seminfo.ts);
+      codestring(v, ls->t.seminfo.ts);
       break;
     }
     case TK_NIL: {
diff --git a/lparser.h b/lparser.h
index d9b734bf..f528f013 100644
--- a/lparser.h
+++ b/lparser.h
@@ -30,7 +30,9 @@ typedef enum {
   VFALSE,  /* constant false */
   VK,  /* constant in 'k'; info = index of constant in 'k' */
   VKFLT,  /* floating constant; nval = numerical float value */
-  VKINT,  /* integer constant; nval = numerical integer value */
+  VKINT,  /* integer constant; ival = numerical integer value */
+  VKSTR,  /* string constant; strval = TString address;
+             (string is fixed by the lexer) */
   VNONRELOC,  /* expression has its value in a fixed register;
                  info = result register */
   VLOCAL,  /* local variable; var.ridx = local register;
@@ -67,6 +69,7 @@ typedef struct expdesc {
   union {
     lua_Integer ival;    /* for VKINT */
     lua_Number nval;  /* for VKFLT */
+    TString *strval;  /* for VKSTR */
     int info;  /* for generic use */
     struct {  /* for indexed variables */
       short idx;  /* index (R or "long" K) */
diff --git a/testes/code.lua b/testes/code.lua
index b2702c61..b5091458 100644
--- a/testes/code.lua
+++ b/testes/code.lua
@@ -409,5 +409,22 @@ checkequal(function () return 6 and true or nil end,
            function () return k6 and kTrue or kNil end)
 
 
+do   -- string constants
+  local function f1 ()
+    local <const> k = "00000000000000000000000000000000000000000000000000"
+    return function ()
+             return function () return k end
+           end
+  end
+
+  local f2 = f1()
+  local f3 = f2()
+  assert(f3() == string.rep("0", 50))
+  checkK(f3, f3())
+  -- string is not needed by other functions
+  assert(T.listk(f1)[1] == nil)
+  assert(T.listk(f2)[1] == nil)
+end
+
 print 'OK'