Handles '__close' errors in coroutines in "coroutine style"

Errors in '__close' metamethods in coroutines are handled by the same
logic that handles other errors, through 'recover'.

testes/coroutine.lua

@@ -123,7 +123,7 @@ assert(#a == 22 and a[#a] == 79)
 x, a = nil
 
 
--- coroutine closing
+print("to-be-closed variables in coroutines")
 
 local function func2close (f)
   return setmetatable({}, {__close = f})
@@ -189,7 +189,6 @@ do
   local st, msg = coroutine.close(co)
   assert(st == false and coroutine.status(co) == "dead" and msg == 200)
   assert(x == 200)
-
 end
 
 do
@@ -207,6 +206,44 @@ do
   local st1, st2, err = coroutine.resume(co)
   assert(st1 and not st2 and err == 43)
   assert(X == 43 and Y.name == "pcall")
+
+  -- recovering from errors in __close metamethods
+  local track = {}
+
+  local function h (o)
+    local hv <close> = o
+    return 1
+  end
+
+  local function foo ()
+    local x <close> = func2close(function(_,msg)
+      track[#track + 1] = msg or false
+      error(20)
+    end)
+    local y <close> = func2close(function(_,msg)
+      track[#track + 1] = msg or false
+      return 1000
+    end)
+    local z <close> = func2close(function(_,msg)
+      track[#track + 1] = msg or false
+      error(10)
+    end)
+    coroutine.yield(1)
+    h(func2close(function(_,msg)
+        track[#track + 1] = msg or false
+        error(2)
+      end))
+  end
+
+  local co = coroutine.create(pcall)
+
+  local st, res = coroutine.resume(co, foo)    -- call 'foo' protected
+  assert(st and res == 1)   -- yield 1
+  local st, res1, res2 = coroutine.resume(co)   -- continue
+  assert(coroutine.status(co) == "dead")
+  assert(st and not res1 and res2 == 20)   -- last error (20)
+  assert(track[1] == false and track[2] == 2 and track[3] == 10 and
+         track[4] == 10)
 end