difftastic/vendored_parsers/tree-sitter-hack/test/cases/expressions/safe-selection.hack

$var?->$var ?? $var ?->$var ? $var?-> $var : $var ?-> $var;

$var[$var?->$var]?->$var[$var?->$var] ??
$var[$var ?->$var] ?->$var[$var ?->$var]
  ? $var[$var?-> $var]?-> $var[$var?-> $var]
  : $var[$var ?-> $var] ?-> $var[$var ?-> $var];