From 0b63d79b36790febd4c081bf8d6737df27529f8d Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Mon, 13 May 2019 16:20:40 -0300
Subject: [PATCH] Details

- 'luaL_setfuncs' avoids creating closures for placeholders.
- Fixed some warnings about unused values in comma expressions.
- Comments.
---
 lauxlib.c | 10 +++++++---
 ldo.c     |  2 +-
 liolib.c  |  2 +-
 ltablib.c |  2 +-
 ltests.c  |  8 +++-----
 5 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/lauxlib.c b/lauxlib.c
index dfe501a7..89e53dc1 100644
--- a/lauxlib.c
+++ b/lauxlib.c
@@ -898,9 +898,13 @@ LUALIB_API void luaL_setfuncs (lua_State *L, const luaL_Reg *l, int nup) {
   luaL_checkstack(L, nup, "too many upvalues");
   for (; l->name != NULL; l++) {  /* fill the table with given functions */
     int i;
-    for (i = 0; i < nup; i++)  /* copy upvalues to the top */
-      lua_pushvalue(L, -nup);
-    lua_pushcclosure(L, l->func, nup);  /* closure with those upvalues */
+    if (l->func == NULL)  /* place holder? */
+      lua_pushboolean(L, 0);
+    else {
+      for (i = 0; i < nup; i++)  /* copy upvalues to the top */
+        lua_pushvalue(L, -nup);
+      lua_pushcclosure(L, l->func, nup);  /* closure with those upvalues */
+    }
     lua_setfield(L, -(nup + 2), l->name);
   }
   lua_pop(L, nup);  /* remove upvalues */
diff --git a/ldo.c b/ldo.c
index e9a88e9e..e7e76a65 100644
--- a/ldo.c
+++ b/ldo.c
@@ -669,7 +669,7 @@ LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs,
     else if (L->top - (L->ci->func + 1) == nargs)  /* no function? */
       return resume_error(L, "cannot resume dead coroutine", nargs);
   }
-  else if (L->status != LUA_YIELD)
+  else if (L->status != LUA_YIELD)  /* ended with errors? */
     return resume_error(L, "cannot resume dead coroutine", nargs);
   if (from == NULL)
     L->nCcalls = 1;
diff --git a/liolib.c b/liolib.c
index 7d6d51e6..fa6a0939 100644
--- a/liolib.c
+++ b/liolib.c
@@ -39,7 +39,7 @@
 /* Check whether 'mode' matches '[rwa]%+?[L_MODEEXT]*' */
 static int l_checkmode (const char *mode) {
   return (*mode != '\0' && strchr("rwa", *(mode++)) != NULL &&
-         (*mode != '+' || (++mode, 1)) &&  /* skip if char is '+' */
+         (*mode != '+' || ((void)(++mode), 1)) &&  /* skip if char is '+' */
          (strspn(mode, L_MODEEXT) == strlen(mode)));  /* check extensions */
 }
 
diff --git a/ltablib.c b/ltablib.c
index a9169f9e..48a6bdfe 100644
--- a/ltablib.c
+++ b/ltablib.c
@@ -299,7 +299,7 @@ static IdxT partition (lua_State *L, IdxT lo, IdxT up) {
   /* loop invariant: a[lo .. i] <= P <= a[j .. up] */
   for (;;) {
     /* next loop: repeat ++i while a[i] < P */
-    while (lua_geti(L, 1, ++i), sort_comp(L, -1, -2)) {
+    while ((void)lua_geti(L, 1, ++i), sort_comp(L, -1, -2)) {
       if (i == up - 1)  /* a[i] < P  but a[up - 1] == P  ?? */
         luaL_error(L, "invalid order function for sorting");
       lua_pop(L, 1);  /* remove a[i] */
diff --git a/ltests.c b/ltests.c
index 7d441d1a..f786eeb3 100644
--- a/ltests.c
+++ b/ltests.c
@@ -51,9 +51,8 @@ static int runC (lua_State *L, lua_State *L1, const char *pc);
 
 
 static void setnameval (lua_State *L, const char *name, int val) {
-  lua_pushstring(L, name);
   lua_pushinteger(L, val);
-  lua_settable(L, -3);
+  lua_setfield(L, -2, name);
 }
 
 
@@ -710,12 +709,11 @@ static void printstack (lua_State *L) {
 
 
 static int get_limits (lua_State *L) {
-  lua_createtable(L, 0, 5);
-  setnameval(L, "BITS_INT", LUAI_BITSINT);
+  lua_createtable(L, 0, 6);
+  setnameval(L, "IS32INT", LUAI_IS32INT);
   setnameval(L, "MAXARG_Ax", MAXARG_Ax);
   setnameval(L, "MAXARG_Bx", MAXARG_Bx);
   setnameval(L, "OFFSET_sBx", OFFSET_sBx);
-  setnameval(L, "BITS_INT", LUAI_BITSINT);
   setnameval(L, "LFPF", LFIELDS_PER_FLUSH);
   setnameval(L, "NUM_OPCODES", NUM_OPCODES);
   return 1;