How deepcopying in Lua may not be enough

copyfail.lua

local node = parser:entry_stat(lex)
local diff_node = copy(node, getmetatable(node))
    
print(node.node_type) -- returns ast.unspecialized.top.Task
print(diff_node.node_type) --  returns ast.unspecialized.top.Task

print(node.node_type == ast.unspecialized.top.Task) -- returns False
print(diff_node.node_type == ast.unspecialized.top.Task) -- returns False

for k, v in pairs(ast.unspecialized.top.Task) do
    print(k, " ", v)
end
-- #Output1
-- print_custom	 	false
-- parent	 	ast.unspecialized.top
-- expected_field_set	 	table: 0x7feecb918720
-- memoize_cache	 	false
-- print_collapsed	 	false
-- expected_fields	 	{span,annotations,name,params,return_type_expr,effect_exprs,body}
-- print_hidden	 	false
-- name	 	Task
-- children	 	{}

for k, v in pairs(node.node_type) do
    print(k, " ", v)
end

-- #Output2
-- print_custom	 	false
-- parent	 	ast.unspecialized.top
-- expected_field_set	 	table: 0x7feecb918720
-- memoize_cache	 	false
-- print_collapsed	 	false
-- expected_fields	 	{span,annotations,name,params,return_type_expr,effect_exprs,body}
-- print_hidden	 	false
-- name	 	Task
-- children	 	{}

for k, v in pairs(diff_node.node_type) do
    print(k, " ", v)
end

-- #Output3
-- print_custom	 	false
-- parent	 	ast.unspecialized.top
-- expected_field_set	 	table: 0x7feec8cbce48
-- children	 	{}
-- print_collapsed	 	false
-- expected_fields	 	{span,annotations,name,params,return_type_expr,effect_exprs,body}
-- print_hidden	 	false
-- name	 	Task
-- memoize_cache	 	false

-- #Output3 differs from #Output1 & #Output2, even with a deepcopy.
-- Look deeper into the metables, or change evaluation conditions for such cases.