Avoid excessive name pollution in test files

Test files are more polite regarding the use of globals when locals
would do, and when globals are necessary deleting them after use.

testes/errors.lua

@@ -114,12 +114,14 @@ checkmessage("a = {} | 1", "bitwise operation")
 checkmessage("a = {} < 1", "attempt to compare")
 checkmessage("a = {} <= 1", "attempt to compare")
 
-checkmessage("a=1; bbbb=2; a=math.sin(3)+bbbb(3)", "global 'bbbb'")
-checkmessage("a={}; do local a=1 end a:bbbb(3)", "method 'bbbb'")
+checkmessage("aaa=1; bbbb=2; aaa=math.sin(3)+bbbb(3)", "global 'bbbb'")
+checkmessage("aaa={}; do local aaa=1 end aaa:bbbb(3)", "method 'bbbb'")
 checkmessage("local a={}; a.bbbb(3)", "field 'bbbb'")
-assert(not string.find(doit"a={13}; local bbbb=1; a[bbbb](3)", "'bbbb'"))
-checkmessage("a={13}; local bbbb=1; a[bbbb](3)", "number")
-checkmessage("a=(1)..{}", "a table value")
+assert(not string.find(doit"aaa={13}; local bbbb=1; aaa[bbbb](3)", "'bbbb'"))
+checkmessage("aaa={13}; local bbbb=1; aaa[bbbb](3)", "number")
+checkmessage("aaa=(1)..{}", "a table value")
+
+_G.aaa, _G.bbbb = nil
 
 -- calls
 checkmessage("local a; a(13)", "local 'a'")
@@ -134,12 +136,13 @@ checkmessage([[
 
 -- tail calls
 checkmessage("local a={}; return a.bbbb(3)", "field 'bbbb'")
-checkmessage("a={}; do local a=1 end; return a:bbbb(3)", "method 'bbbb'")
+checkmessage("aaa={}; do local aaa=1 end; return aaa:bbbb(3)", "method 'bbbb'")
 
-checkmessage("a = #print", "length of a function value")
-checkmessage("a = #3", "length of a number value")
+checkmessage("aaa = #print", "length of a function value")
+checkmessage("aaa = #3", "length of a number value")
+
+_G.aaa = nil
 
-aaa = nil
 checkmessage("aaa.bbb:ddd(9)", "global 'aaa'")
 checkmessage("local aaa={bbb=1}; aaa.bbb:ddd(9)", "field 'bbb'")
 checkmessage("local aaa={bbb={}}; aaa.bbb:ddd(9)", "method 'ddd'")
@@ -152,15 +155,16 @@ checkmessage("local a,b,cc; (function () a.x = 1 end)()", "upvalue 'a'")
 
 checkmessage("local _ENV = {x={}}; a = a + 1", "global 'a'")
 
-checkmessage("b=1; local aaa={}; x=aaa+b", "local 'aaa'")
+checkmessage("BB=1; local aaa={}; x=aaa+BB", "local 'aaa'")
 checkmessage("aaa={}; x=3.3/aaa", "global 'aaa'")
-checkmessage("aaa=2; b=nil;x=aaa*b", "global 'b'")
+checkmessage("aaa=2; BB=nil;x=aaa*BB", "global 'BB'")
 checkmessage("aaa={}; x=-aaa", "global 'aaa'")
 
 -- short circuit
-checkmessage("a=1; local a,bbbb=2,3; a = math.sin(1) and bbbb(3)",
+checkmessage("aaa=1; local aaa,bbbb=2,3; aaa = math.sin(1) and bbbb(3)",
        "local 'bbbb'")
-checkmessage("a=1; local a,bbbb=2,3; a = bbbb(1) or a(3)", "local 'bbbb'")
+checkmessage("aaa=1; local aaa,bbbb=2,3; aaa = bbbb(1) or aaa(3)",
+             "local 'bbbb'")
 checkmessage("local a,b,c,f = 1,1,1; f((a and b) or c)", "local 'f'")
 checkmessage("local a,b,c = 1,1,1; ((a and b) or c)()", "call a number value")
 assert(not string.find(doit"aaa={}; x=(aaa or aaa)+(aaa and aaa)", "'aaa'"))
@@ -187,8 +191,8 @@ checkmessage("return ~-3e40", "has no integer representation")
 checkmessage("return ~-3.009", "has no integer representation")
 checkmessage("return 3.009 & 1", "has no integer representation")
 checkmessage("return 34 >> {}", "table value")
-checkmessage("a = 24 // 0", "divide by zero")
-checkmessage("a = 1 % 0", "'n%0'")
+checkmessage("aaa = 24 // 0", "divide by zero")
+checkmessage("aaa = 1 % 0", "'n%0'")
 
 
 -- type error for an object which is neither in an upvalue nor a register.
@@ -269,13 +273,13 @@ end
 -- tests for field accesses after RK limit
 local t = {}
 for i = 1, 1000 do
-  t[i] = "a = x" .. i
+  t[i] = "aaa = x" .. i
 end
 local s = table.concat(t, "; ")
 t = nil
-checkmessage(s.."; a = bbb + 1", "global 'bbb'")
-checkmessage("local _ENV=_ENV;"..s.."; a = bbb + 1", "global 'bbb'")
-checkmessage(s.."; local t = {}; a = t.bbb + 1", "field 'bbb'")
+checkmessage(s.."; aaa = bbb + 1", "global 'bbb'")
+checkmessage("local _ENV=_ENV;"..s.."; aaa = bbb + 1", "global 'bbb'")
+checkmessage(s.."; local t = {}; aaa = t.bbb + 1", "field 'bbb'")
 checkmessage(s.."; local t = {}; t:bbb()", "method 'bbb'")
 
 checkmessage([[aaa=9
@@ -324,14 +328,17 @@ main()
 ]], "global 'NoSuchName'")
 print'+'
 
-a = {}; setmetatable(a, {__index = string})
-checkmessage("a:sub()", "bad self")
+aaa = {}; setmetatable(aaa, {__index = string})
+checkmessage("aaa:sub()", "bad self")
 checkmessage("string.sub('a', {})", "#2")
 checkmessage("('a'):sub{}", "#1")
 
 checkmessage("table.sort({1,2,3}, table.sort)", "'table.sort'")
 checkmessage("string.gsub('s', 's', setmetatable)", "'setmetatable'")
 
+_G.aaa = nil
+
+
 -- tests for errors in coroutines
 
 local function f (n)
@@ -349,7 +356,7 @@ checkerr("yield across", f)
 
 -- testing size of 'source' info; size of buffer for that info is
 -- LUA_IDSIZE, declared as 60 in luaconf. Get one position for '\0'.
-idsize = 60 - 1
+local idsize = 60 - 1
 local function checksize (source)
   -- syntax error
   local _, msg = load("x", source)
@@ -411,13 +418,14 @@ x
 
 local p = [[
   function g() f() end
-  function f(x) error('a', X) end
+  function f(x) error('a', XX) end
 g()
 ]]
-X=3;lineerror((p), 3)
-X=0;lineerror((p), false)
-X=1;lineerror((p), 2)
-X=2;lineerror((p), 1)
+XX=3;lineerror((p), 3)
+XX=0;lineerror((p), false)
+XX=1;lineerror((p), 2)
+XX=2;lineerror((p), 1)
+_G.XX, _G.g, _G.f = nil
 
 
 lineerror([[
@@ -449,11 +457,11 @@ if not _soft then
   -- several tests that exaust the Lua stack
   collectgarbage()
   print"testing stack overflow"
-  C = 0
+  local C = 0
   -- get line where stack overflow will happen
   local l = debug.getinfo(1, "l").currentline + 1
   local function auxy () C=C+1; auxy() end     -- produce a stack overflow
-  function y ()
+  function YY ()
     collectgarbage("stop")   -- avoid running finalizers without stack space
     auxy()
     collectgarbage("restart")
@@ -465,9 +473,11 @@ if not _soft then
     return (string.find(m, "stack overflow"))
   end
   -- repeated stack overflows (to check stack recovery)
-  assert(checkstackmessage(doit('y()')))
-  assert(checkstackmessage(doit('y()')))
-  assert(checkstackmessage(doit('y()')))
+  assert(checkstackmessage(doit('YY()')))
+  assert(checkstackmessage(doit('YY()')))
+  assert(checkstackmessage(doit('YY()')))
+
+  _G.YY = nil
 
 
   -- error lines in stack overflow
@@ -561,7 +571,7 @@ do
 end
 
 -- xpcall with arguments
-a, b, c = xpcall(string.find, error, "alo", "al")
+local a, b, c = xpcall(string.find, error, "alo", "al")
 assert(a and b == 1 and c == 2)
 a, b, c = xpcall(string.find, function (x) return {} end, true, "al")
 assert(not a and type(b) == "table" and c == nil)
@@ -581,11 +591,12 @@ checksyntax("a\1a = 1", "", "<\\1>", 1)
 -- test 255 as first char in a chunk
 checksyntax("\255a = 1", "", "<\\255>", 1)
 
-doit('I = load("a=9+"); a=3')
-assert(a==3 and not I)
+doit('I = load("a=9+"); aaa=3')
+assert(_G.aaa==3 and not _G.I)
+_G.I,_G.aaa = nil
 print('+')
 
-lim = 1000
+local lim = 1000
 if _soft then lim = 100 end
 for i=1,lim do
   doit('a = ')