Proper error message when jumping into 'global *'

A goto cannot jump into the scope of any variable declaration,
including 'global *'. To report the error, it needs a "name" for
the scope it is entering.

lparser.c

@@ -542,13 +542,13 @@ 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 *varname = (tsname != NULL) ? getstr(tsname) : "*";
   luaK_semerror(ls,
-     "<goto %s> at line %d jumps into the scope of local '%s'",
+     "<goto %s> at line %d jumps into the scope of '%s'",
       getstr(gt->name), gt->line, varname);  /* raise the error */
 }
 

manual/manual.of

@@ -1504,7 +1504,7 @@ 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.

testes/goto.lua

@@ -23,15 +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'")
@@ -44,7 +47,7 @@ errmsg([[
     local xuxu = 10
     ::cont::
   until xuxu < x
-]], "local 'xuxu'")
+]], "scope of 'xuxu'")
 
 -- simple gotos
 local x