```
-- bug since 2.5 (C-stack overflow)
do
local function f (size)
local s = string.rep("a", size)
local p = string.rep(".?", size)
return pcall(string.match, s, p)
end
local r, m = f(80)
assert(r and #m == 80)
r, m = f(200000)
assert(not r and string.find(m, "too complex"), tostring(r)..", "..tostring(m))
end
```