Static analysis issue in version 3.4.0

[roelfdutoit]

Static analysis on Inja version 3.4.0 with clang-tidy fails on the following (sanitized code):

inja/parser.hpp:626:5: error: Address of stack memory associated with local variable 'result' is still referred to by the stack v
ariable 'parser' upon returning to the caller.  This will be a dangling reference [clang-analyzer-core.StackAddressEscape,-warnings-as-errors]
    return result;
    ^                                                                                                                                                                                                            

test.cc:151:40: note: Calling 'Environment::render'
    const std::string updated_config = env.render(config, data);
                                       ^~~~~~~~~~~~~~~~~~~~~~~~
inja/environment.hpp:113:19: note: Calling 'Environment::parse'                                                                                                                                                                                 
    return render(parse(input), data);
                  ^~~~~~~~~~~~
inja/environment.hpp:98:12: note: Calling 'Parser::parse'
    return parser.parse(input, input_path);
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
inja/parser.hpp:626:5: note: Address of stack memory associated with local variable 'result' is still referred to by the stack variable 'parser' upon returning to the caller.  This will be a dangling reference
    return result;
    ^

The issue seems to be this code in parser.hpp:

  void parse_into(Template& tmpl, std::string_view path) {
    lexer.start(tmpl.content);
    current_block = &tmpl.root;
    :

.. where current_block is holding a pointer to the input Template, which happens to be on the stack in this code:

  Template parse(std::string_view input, std::string_view path) {
    auto result = Template(static_cast<std::string>(input));
    parse_into(result, path);
    return result;
  }